what is the presentation of global warming

ENCYCLOPEDIC ENTRY

Global warming.

The causes, effects, and complexities of global warming are important to understand so that we can fight for the health of our planet.

Earth Science, Climatology

Tennessee Power Plant

Ash spews from a coal-fueled power plant in New Johnsonville, Tennessee, United States.

Photograph by Emory Kristof/ National Geographic

Global warming is the long-term warming of the planet’s overall temperature. Though this warming trend has been going on for a long time, its pace has significantly increased in the last hundred years due to the burning of fossil fuels . As the human population has increased, so has the volume of fossil fuels burned. Fossil fuels include coal, oil, and natural gas, and burning them causes what is known as the “greenhouse effect” in Earth’s atmosphere.

The greenhouse effect is when the sun’s rays penetrate the atmosphere, but when that heat is reflected off the surface cannot escape back into space. Gases produced by the burning of fossil fuels prevent the heat from leaving the atmosphere. These greenhouse gasses are carbon dioxide , chlorofluorocarbons, water vapor , methane , and nitrous oxide . The excess heat in the atmosphere has caused the average global temperature to rise overtime, otherwise known as global warming.

Global warming has presented another issue called climate change. Sometimes these phrases are used interchangeably, however, they are different. Climate change refers to changes in weather patterns and growing seasons around the world. It also refers to sea level rise caused by the expansion of warmer seas and melting ice sheets and glaciers . Global warming causes climate change, which poses a serious threat to life on Earth in the forms of widespread flooding and extreme weather. Scientists continue to study global warming and its impact on Earth.

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What is global warming?

What causes global warming, how is global warming linked to extreme weather, what are the other effects of global warming, where does the united states stand in terms of global-warming contributors, is the united states doing anything to prevent global warming, is global warming too big a problem for me to help tackle.

A: Since the Industrial Revolution, the global annual temperature has increased in total by a little more than 1 degree Celsius, or about 2 degrees Fahrenheit. Between 1880—the year that accurate recordkeeping began—and 1980, it rose on average by 0.07 degrees Celsius (0.13 degrees Fahrenheit) every 10 years. Since 1981, however, the rate of increase has more than doubled: For the last 40 years, we’ve seen the global annual temperature rise by 0.18 degrees Celsius, or 0.32 degrees Fahrenheit, per decade.

The result? A planet that has never been hotter . Nine of the 10 warmest years since 1880 have occurred since 2005—and the 5 warmest years on record have all occurred since 2015. Climate change deniers have argued that there has been a “pause” or a “slowdown” in rising global temperatures, but numerous studies, including a 2018 paper published in the journal Environmental Research Letters , have disproved this claim. The impacts of global warming are already harming people around the world.

Now climate scientists have concluded that we must limit global warming to 1.5 degrees Celsius by 2040 if we are to avoid a future in which everyday life around the world is marked by its worst, most devastating effects: the extreme droughts, wildfires, floods, tropical storms, and other disasters that we refer to collectively as climate change . These effects are felt by all people in one way or another but are experienced most acutely by the underprivileged, the economically marginalized, and people of color, for whom climate change is often a key driver of poverty, displacement, hunger, and social unrest.

A: Global warming occurs when carbon dioxide (CO 2 ) and other air pollutants collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the earth’s surface. Normally this radiation would escape into space, but these pollutants, which can last for years to centuries in the atmosphere, trap the heat and cause the planet to get hotter. These heat-trapping pollutants—specifically carbon dioxide, methane, nitrous oxide, water vapor, and synthetic fluorinated gases—are known as greenhouse gases, and their impact is called the greenhouse effect.

Though natural cycles and fluctuations have caused the earth’s climate to change several times over the last 800,000 years, our current era of global warming is directly attributable to human activity—specifically to our burning of fossil fuels such as coal, oil, gasoline, and natural gas, which results in the greenhouse effect. In the United States, the largest source of greenhouse gases is transportation (29 percent), followed closely by electricity production (28 percent) and industrial activity (22 percent). Learn about the natural and human causes of climate change .

Curbing dangerous climate change requires very deep cuts in emissions, as well as the use of alternatives to fossil fuels worldwide. The good news is that countries around the globe have formally committed—as part of the 2015 Paris Climate Agreement —to lower their emissions by setting new standards and crafting new policies to meet or even exceed those standards. The not-so-good news is that we’re not working fast enough. To avoid the worst impacts of climate change, scientists tell us that we need to reduce global carbon emissions by as much as 40 percent by 2030. For that to happen, the global community must take immediate, concrete steps: to decarbonize electricity generation by equitably transitioning from fossil fuel–based production to renewable energy sources like wind and solar; to electrify our cars and trucks; and to maximize energy efficiency in our buildings, appliances, and industries.

A: Scientists agree that the earth’s rising temperatures are fueling longer and hotter heat waves , more frequent droughts , heavier rainfall , and more powerful hurricanes .

In 2015, for example, scientists concluded that a lengthy drought in California—the state’s worst water shortage in 1,200 years —had been intensified by 15 to 20 percent by global warming. They also said the odds of similar droughts happening in the future had roughly doubled over the past century. And in 2016, the National Academies of Science, Engineering, and Medicine announced that we can now confidently attribute some extreme weather events, like heat waves, droughts, and heavy precipitation, directly to climate change.

The earth’s ocean temperatures are getting warmer, too—which means that tropical storms can pick up more energy. In other words, global warming has the ability to turn a category 3 storm into a more dangerous category 4 storm. In fact, scientists have found that the frequency of North Atlantic hurricanes has increased since the early 1980s, as has the number of storms that reach categories 4 and 5. The 2020 Atlantic hurricane season included a record-breaking 30 tropical storms, 6 major hurricanes, and 13 hurricanes altogether. With increased intensity come increased damage and death. The United States saw an unprecedented 22 weather and climate disasters that caused at least a billion dollars’ worth of damage in 2020, but, according to NOAA, 2017 was the costliest on record and among the deadliest as well: Taken together, that year's tropical storms (including Hurricanes Harvey, Irma, and Maria) caused nearly $300 billion in damage and led to more than 3,300 fatalities.

The impacts of global warming are being felt everywhere. Extreme heat waves have caused tens of thousands of deaths around the world in recent years. And in an alarming sign of events to come, Antarctica has lost nearly four trillion metric tons of ice since the 1990s. The rate of loss could speed up if we keep burning fossil fuels at our current pace, some experts say, causing sea levels to rise several meters in the next 50 to 150 years and wreaking havoc on coastal communities worldwide.

A: Each year scientists learn more about the consequences of global warming , and each year we also gain new evidence of its devastating impact on people and the planet. As the heat waves, droughts, and floods associated with climate change become more frequent and more intense, communities suffer and death tolls rise. If we’re unable to reduce our emissions, scientists believe that climate change could lead to the deaths of more than 250,000 people around the globe every year and force 100 million people into poverty by 2030.

Global warming is already taking a toll on the United States. And if we aren’t able to get a handle on our emissions, here’s just a smattering of what we can look forward to:

• Disappearing glaciers, early snowmelt, and severe droughts will cause more dramatic water shortages and continue to increase the risk of wildfires in the American West.
• Rising sea levels will lead to even more coastal flooding on the Eastern Seaboard, especially in Florida, and in other areas such as the Gulf of Mexico.
• Forests, farms, and cities will face troublesome new pests , heat waves, heavy downpours, and increased flooding . All of these can damage or destroy agriculture and fisheries.
• Disruption of habitats such as coral reefs and alpine meadows could drive many plant and animal species to extinction.
• Allergies, asthma, and infectious disease outbreaks will become more common due to increased growth of pollen-producing ragweed , higher levels of air pollution , and the spread of conditions favorable to pathogens and mosquitoes.

Though everyone is affected by climate change, not everyone is affected equally. Indigenous people, people of color, and the economically marginalized are typically hit the hardest. Inequities built into our housing , health care , and labor systems make these communities more vulnerable to the worst impacts of climate change—even though these same communities have done the least to contribute to it.

A: In recent years, China has taken the lead in global-warming pollution , producing about 26 percent of all CO2 emissions. The United States comes in second. Despite making up just 4 percent of the world’s population, our nation produces a sobering 13 percent of all global CO2 emissions—nearly as much as the European Union and India (third and fourth place) combined. And America is still number one, by far, in cumulative emissions over the past 150 years. As a top contributor to global warming, the United States has an obligation to help propel the world to a cleaner, safer, and more equitable future. Our responsibility matters to other countries, and it should matter to us, too.

A: We’ve started. But in order to avoid the worsening effects of climate change, we need to do a lot more—together with other countries—to reduce our dependence on fossil fuels and transition to clean energy sources.

Under the administration of President Donald Trump (a man who falsely referred to global warming as a “hoax”), the United States withdrew from the Paris Climate Agreement, rolled back or eliminated dozens of clean air protections, and opened up federally managed lands, including culturally sacred national monuments, to fossil fuel development. Although President Biden has pledged to get the country back on track, years of inaction during and before the Trump administration—and our increased understanding of global warming’s serious impacts—mean we must accelerate our efforts to reduce greenhouse gas emissions.

Despite the lack of cooperation from the Trump administration, local and state governments made great strides during this period through efforts like the American Cities Climate Challenge and ongoing collaborations like the Regional Greenhouse Gas Initiative . Meanwhile, industry and business leaders have been working with the public sector, creating and adopting new clean-energy technologies and increasing energy efficiency in buildings, appliances, and industrial processes. 

Today the American automotive industry is finding new ways to produce cars and trucks that are more fuel efficient and is committing itself to putting more and more zero-emission electric vehicles on the road. Developers, cities, and community advocates are coming together to make sure that new affordable housing is built with efficiency in mind , reducing energy consumption and lowering electric and heating bills for residents. And renewable energy continues to surge as the costs associated with its production and distribution keep falling. In 2020 renewable energy sources such as wind and solar provided more electricity than coal for the very first time in U.S. history.

President Biden has made action on global warming a high priority. On his first day in office, he recommitted the United States to the Paris Climate Agreement, sending the world community a strong signal that we were determined to join other nations in cutting our carbon pollution to support the shared goal of preventing the average global temperature from rising more than 1.5 degrees Celsius above preindustrial levels. (Scientists say we must stay below a 2-degree increase to avoid catastrophic climate impacts.) And significantly, the president has assembled a climate team of experts and advocates who have been tasked with pursuing action both abroad and at home while furthering the cause of environmental justice and investing in nature-based solutions.

A: No! While we can’t win the fight without large-scale government action at the national level , we also can’t do it without the help of individuals who are willing to use their voices, hold government and industry leaders to account, and make changes in their daily habits.

Wondering how you can be a part of the fight against global warming? Reduce your own carbon footprint by taking a few easy steps: Make conserving energy a part of your daily routine and your decisions as a consumer. When you shop for new appliances like refrigerators, washers, and dryers, look for products with the government’s ENERGY STAR ® label; they meet a higher standard for energy efficiency than the minimum federal requirements. When you buy a car, look for one with the highest gas mileage and lowest emissions. You can also reduce your emissions by taking public transportation or carpooling when possible.

And while new federal and state standards are a step in the right direction, much more needs to be done. Voice your support of climate-friendly and climate change preparedness policies, and tell your representatives that equitably transitioning from dirty fossil fuels to clean power should be a top priority—because it’s vital to building healthy, more secure communities.

You don’t have to go it alone, either. Movements across the country are showing how climate action can build community , be led by those on the front lines of its impacts, and create a future that’s equitable and just for all .

This story was originally published on March 11, 2016 and has been updated with new information and links.

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What Is Climate Change?

Climate change is a long-term change in the average weather patterns that have come to define Earth’s local, regional and global climates. These changes have a broad range of observed effects that are synonymous with the term.

Changes observed in Earth’s climate since the mid-20th century are driven by human activities, particularly fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere, raising Earth’s average surface temperature. Natural processes, which have been overwhelmed by human activities, can also contribute to climate change, including internal variability (e.g., cyclical ocean patterns like El Niño, La Niña and the Pacific Decadal Oscillation) and external forcings (e.g., volcanic activity, changes in the Sun’s energy output , variations in Earth’s orbit ).

Scientists use observations from the ground, air, and space, along with computer models , to monitor and study past, present, and future climate change. Climate data records provide evidence of climate change key indicators, such as global land and ocean temperature increases; rising sea levels; ice loss at Earth’s poles and in mountain glaciers; frequency and severity changes in extreme weather such as hurricanes, heatwaves, wildfires, droughts, floods, and precipitation; and cloud and vegetation cover changes.

“Climate change” and “global warming” are often used interchangeably but have distinct meanings. Similarly, the terms "weather" and "climate" are sometimes confused, though they refer to events with broadly different spatial- and timescales.

What Is Global Warming?

Global warming is the long-term heating of Earth’s surface observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere. This term is not interchangeable with the term "climate change."

Since the pre-industrial period, human activities are estimated to have increased Earth’s global average temperature by about 1 degree Celsius (1.8 degrees Fahrenheit), a number that is currently increasing by more than 0.2 degrees Celsius (0.36 degrees Fahrenheit) per decade. The current warming trend is unequivocally the result of human activity since the 1950s and is proceeding at an unprecedented rate over millennia.

Weather vs. Climate

“if you don’t like the weather in new england, just wait a few minutes.” - mark twain.

Weather refers to atmospheric conditions that occur locally over short periods of time—from minutes to hours or days. Familiar examples include rain, snow, clouds, winds, floods, or thunderstorms.

Climate, on the other hand, refers to the long-term (usually at least 30 years) regional or even global average of temperature, humidity, and rainfall patterns over seasons, years, or decades.

Find Out More: A Guide to NASA’s Global Climate Change Website

This website provides a high-level overview of some of the known causes, effects and indications of global climate change:

Evidence. Brief descriptions of some of the key scientific observations that our planet is undergoing abrupt climate change.

Causes. A concise discussion of the primary climate change causes on our planet.

Effects. A look at some of the likely future effects of climate change, including U.S. regional effects.

Vital Signs. Graphs and animated time series showing real-time climate change data, including atmospheric carbon dioxide, global temperature, sea ice extent, and ice sheet volume.

Earth Minute. This fun video series explains various Earth science topics, including some climate change topics.

Other NASA Resources

Goddard Scientific Visualization Studio. An extensive collection of animated climate change and Earth science visualizations.

Sea Level Change Portal. NASA's portal for an in-depth look at the science behind sea level change.

NASA’s Earth Observatory. Satellite imagery, feature articles and scientific information about our home planet, with a focus on Earth’s climate and environmental change.

Header image is of Apusiaajik Glacier, and was taken near Kulusuk, Greenland, on Aug. 26, 2018, during NASA's Oceans Melting Greenland (OMG) field operations. Learn more here . Credit: NASA/JPL-Caltech

Discover More Topics From NASA

Explore Earth Science

Earth Science in Action

Earth Science Data

Facts About Earth

Global warming frequently asked questions

] Earth’s average surface temperature has risen by 1.8°F (1.0°C) since the late 1800s, an average rate of 0.13° F (0.07° C) per decade. Since 1981, the rate of warming has more than doubled to 0.32°F (0.18°C) per decade. The six warmest years in the 1880–2020 record have all occurred since 2014, while 19 of the 20 warmest years have occurred since 2001.  ] With significant reductions in the emissions of greenhouse gases, the annual global surface temperature rise this century could be limited to 3.6°F (2°C) or less. Without major reductions in these emissions, the increase in annual average global temperatures relative to preindustrial times could reach 9°F (5°C) or more by the end of this century. ] Learn more and .

] Thanks to natural climate variability, volcanic eruptions, and to a smaller extent, low solar activity, the rate of average global warming from 1998–2013 was slower than it had been over the two preceding decades. Such varations in the rate of warming from decade to decade are common. ] Meanwhile, excess heat continued to accumulate in the deeper layers of the ocean, contributing to marine heat waves and sea level rise. ] The slowdown in surface warming was only temporary, however, as the six warmest years in recorded history have all occurred after 2013. ] Learn more and

. and and . . ] Carbon dioxide, methane, nitrous oxide, ozone, and various chlorofluorocarbons are all human-emitted . Among these, carbon dioxide is of greatest concern to scientists because it exerts a larger overall warming influence than the .

At present, humans are putting an estimated 9.5 billion metric tons of carbon into the atmosphere each year by burning fossil fuels, and another 1.5 billion through deforestation and other land cover changes. Of this human-produced carbon, forests and other vegetation absorb around 3.2 billion metric tons per year, while the ocean absorbs about 2.5 billion metric tons per year. A net 5 billion metric tons of human-produced carbon remain in the atmosphere each year, raising the global average carbon dioxide concentrations by about 2.3 parts per million per year. Since 1750, humans have increased the abundance of carbon dioxide in the atmosphere by nearly 50 percent. ]  .

and ?

generally refers to the long-term increase in global average temperature as a result of human activity. Climate change is a much broader term that covers changes in multiple parts of the climate system, from temperature to precipitation to wind patterns. Climate change can be local, regional, or global, and it can have natural or human causes. Global warming is a type of climate change; however, not all climate change is global warming. .

] When different teams of climate scientists in different agencies (e.g., NOAA and NASA) and in other countries (e.g., the U.K.’s Hadley Centre) average these data together, they all find essentially the same result: Earth’s average surface temperature has risen by about 1.8°F (1.0°C) since 1880. ]

In addition to our surface station data, we have many different lines of evidence that Earth is warming ( ). Birds are migrating earlier, and their migration patterns are changing. and are moving north. Plants are blooming earlier in the spring. Mountain glaciers are melting and snow cover is declining in the Northern Hemisphere (Learn more and ). Greenland’s ice sheet—which holds about 8 percent of Earth’s fresh water—is melting at an accelerating rate ( ). Mean global sea level is rising ( ). Arctic sea ice is declining rapidly in both thickness and extent ( ).

We know this warming is largely caused by human activities because the key role that carbon dioxide plays in maintaining Earth’s natural greenhouse effect has been understood since the mid-1800s. Unless it is offset by some equally large cooling influence, more atmospheric carbon dioxide will lead to warmer surface temperatures. Since 1800, the amount of carbon dioxide in the atmosphere from about 280 parts per million to 410 ppm in 2019. We know from both its rapid increase and its isotopic “fingerprint” that the source of this new carbon dioxide is fossil fuels, and not natural sources like forest fires, volcanoes, or outgassing from the ocean.

Finally, no other known climate influences have changed enough to account for the observed warming trend. Taken together, these and other lines of evidence point squarely to human activities as the cause of recent global warming.

] In addition, fossil fuels are the only source of carbon consistent with the of the carbon present in today’s atmosphere. That analysis indicates it must be coming from terrestrial plant matter, and it must be very, very old. These and other lines of evidence leave no doubt that fossil fuels are the primary source of the carbon dioxide building up in Earth’s atmosphere.

] [ ] [ ] [ ]

This scientific consensus is clearly summarized in the climate assessment reports of the U.S. Global Change Research Program and the Intergovernmental Panel on Climate Change. ] [ ] [ ] NOAA scientists played lead roles in authoring and editing both sets of reports.

Additionally, the United States’ foremost science agencies and organizations have all recognized global warming as a human-caused problem that threatens human and natural systems and, therefore, should be addressed. These agencies and organizations include (but are not limited to) ; the ; the ; the ; the ; the ; the ; the ; the ; and the .

is the short-term atmospheric conditions at a given location on a specific day and time. is usually described as the long-term average weather at a given place, but it the range of weather conditions that are possible at a given place, including the types and historical frequency of extreme events that occur there. By analogy, if the outcome of any given at-bat is like the weather, then a baseball player’s career batting average is like the climate. There’s an old saying: “Climate is what you expect; weather is what you get.”

Another way to think about the difference between weather and climate is to say that a region’s climate is the background conditions that give rise to a location’s weather events. Because all weather occurs within Earth’s climate system, changes in the background state of the climate system can make different weather outcomes more or less likely to happen. For example, during the period from 1997-2018, the percentage area of the globe that experienced record-setting warm temperatures dwarfed the percentage area of the globe that experienced record-setting cold temperatures. ] This was a predictable set of weather outcomes due to global warming. .

conditions and climate is about conditions. Climate models are not trying, for example, to forecast the daytime high temperature in Chicago, IL, on August 15, 2035. They are trying to forecast the daytime high temperature for the of August over the entire of the 2030s. And while the exact weather conditions at a given location can change dramatically from hour to hour, the average changes much less from year to year or even decade to decade. The difference in time scale means that our ability to predict future climate doesn’t depend on our ability to predict next week’s weather.

Not only are weather models predicting different things than climate models, they require different kinds of starting information. Modelers call weather forecasting an problem because, at short time scales, the future atmospheric conditions depend mostly on the initial atmospheric conditions. The accuracy of your forecast for a given location depends heavily on how well you can describe these initial conditions, especially in the surrounding area.

In contrast, most modelers describe a climate projection as a problem because at long time scales (years to decades), future climate depends mostly on big-picture characteristics of the Earth system that don’t vary from day to day: the amount of land and ocean surface, the height and location of mountain ranges, the geometry of Earth’s orbit, and—crucially—the composition of the global atmosphere. These things define the boundaries of the climate system, the relatively narrow range of outcomes that are possible over long time frames.

These fundamental differences between weather models and climate models, in both what they are trying to predict and what those predictions depend on, mean that the quality of a weather forecast two weeks out isn’t a good test of how well we can predict the climate two decades out.

since the mid-1800s. The more greenhouse gases in the atmosphere, the more heat energy the atmosphere traps near the surface ( ), causing Earth’s surface temperature to rise.

The initial warming due to increasing carbon dioxide kicks off several feedback loops: more water vapor, which is a powerful greenhouse gas; permafrost thaw and decomposition, which releases more methane and carbon dioxide; loss of sea ice and snow, which reduces the amount of sunlight the Earth reflects; and outgassing of additional carbon dioxide from the ocean. Together, these feedback loops make the actual warming two or more times larger than it would be due to carbon dioxide increases alone. ]

] So in terms of total warming, water vapor is the most important greenhouse gas. But without the background warmth provided by carbon dioxide—which doesn’t condense and rain out of the atmosphere as water vapor does—the atmosphere would be too cold to support much water vapor, and the entire greenhouse effect would collapse. Models indicate Earth would likely freeze over everywhere but the equator. ] So in terms of making the greenhouse effect , carbon dioxide is the most important greenhouse gas.

As the most abundant of the non-condensing , carbon dioxide is the main control knob—the thermostat—of Earth’s greenhouse effect. ] Increases in atmospheric carbon dioxide from human activities are turning the thermostat up. As surface temperatures rise, more water evaporates, enhancing the initial warming. This water vapor feedback loop is powerful, at least doubling the warming provided by carbon dioxide alone. ] [ ] [ ] But water vapor can’t act on its own to cause climate change; it can only amplify a change caused by the non-condensing greenhouse gases or other climate influences, such as variations in incoming sunlight. That means that when it comes to causing global warming, carbon dioxide is without question the most important greenhouse gas.

]  ]  ]  ] It was partly through their attempts to understand previous ice ages that climate scientists came to understand the dominant role that carbon dioxide plays in Earth’s climate system, and the role it is playing in current global warming. Learn more and .

Over at least the past million years, have been triggered by in how much sunlight reaches the Northern Hemisphere in the summer, which are driven by small variations in the geometry of Earth’s orbit around the Sun. But these fluctuations in sunlight aren’t enough on their own to bring about full-blown ice ages and interglacials. They trigger several that amplify the original warming or cooling. During an interglacial,

These feedbacks until the Earth’s orbit goes through a phase during which the amount of Northern Hemisphere summer sunlight is minimized. Then these feedbacks operate in reverse, reinforcing the cooling trend.

During all the ice ages that have occurred over at least the past million years, these opposing branches of the carbon cycle have kept the atmospheric carbon dioxide level at or below 300 parts per million (ppm). ] , that level is close to 410 ppm. Not only is this the highest carbon dioxide has been during all of human civilization, it has reached these levels virtually instantaneously in geologic time frames. During ice age cycles of the past, a change this large would likely have taken thousands of years to occur.

This extremely rapid build-up of carbon dioxide is happening because humans are putting carbon dioxide into the atmosphere faster than natural sinks can remove it. By burning fossil fuels, we have essentially taken millions of years of carbon uptake by plants and returned it to the atmosphere in . ]

] to perhaps as much as 0.6 billion metric tons ], whereas human activities have been releasing more than 30 billion metric tons of carbon dioxide per year ] 

up to 0.1°C of the 1.0°C (1.8°F) of warming observed since the pre-industrial era. ] However, there has been no significant net change in the Sun’s energy output from the late 1970s to the present, which is when we have observed the most rapid global warming. .

A second reason that scientists have ruled out a significant role for the Sun in global warming is that if the Sun’s energy output had intensified, we would expect all layers of Earth’s atmosphere to have warmed. But we don’t see that. Rather, satellites and observations from weather balloons show warming in the lower atmosphere (troposphere) and cooling in the upper stratosphere (stratosphere)—which is exactly what we would expect to see as a result of increasing greenhouse gases trapping heat in the lower atmosphere. ] Scientists regard this piece of evidence as one of several “smoking guns” linking today’s global warming to human-emitted, heat-trapping gases.

are smaller than the warming influence of the heat-trapping gases humans put into the air. ]

Our greatest cooling influence comes from particulate pollution (aerosols) we produce. We put plumes of aerosols into the air from power plants and industrial smokestacks; smoke and gases from biomass burning; windblown dust from deforested areas, dried wetlands, and crop fields; exhaust from ships’ smokestacks; tailpipe emissions from cars, trucks, buses, and trains; etc. Aerosol particles absorb and reflect the sun’s rays, thereby reducing the amount of sunlight reaching Earth’s surface. They also interact with clouds, in many cases making them brighter and longer-lived, also reducing the amount of sunlight reaching the surface. .

Whereas aerosols linger in the atmosphere from days to a few weeks, heat-trapping gases that we add to the atmosphere linger from decades to centuries. Plus, when scientists discovered that our aerosol emissions were causing other undesired harmful side effects—such as acid rain and human respiratory diseases and deaths—we began to regulate and reduce their emission. Thus, the warming effect of our heat-trapping gases is ultimately winning out over the cooling influence of our particle pollution. .

makes it harder for shell-building marine life—including commercially and culturally valuable species such as coral, crabs, and oysters—to build and maintain their shells. ]

Because of its tremendous volume and high heat capacity, the ocean has absorbed more than 90 percent of all excess heat trapped in Earth's climate system by greenhouse gases. Currents mix much of that heat into deeper layers of the ocean, delaying the full impact of surface warming we would otherwise expect. However, the heating of deeper layers of the ocean still contributes to sea level rise, sea ice retreat, marine heatwaves, oxygen depletion and expanding dead zones, shifts in the ranges of several marine species, and accelerating loss of polar ice shelves. ]

and not necessarily in all seasons. It’s like your grades—if you get Bs and Cs in your first semester and in the next semester you get all As and Cs, your overall grade point average rises even though you didn’t improve in every class. Differences in exposure to sunlight, cloud cover, atmospheric circulation patterns, aerosol concentrations, atmospheric humidity, land surface cover, etc., all vary from place to place which, in turn, influence whether and how much a location is warming or cooling. Learn more , , , and .

Generally speaking, an extreme event is any event that ranks in the highest or lowest 5 percent or 10 percent of all historical observations of that type of event. The percentage threshold is arbitrary and is designated by a researcher to provide context on a given event or set of events.

Scientists sometimes describe extreme events in terms of their “sigmas” (or their “standard deviation”), which is a measure of how far removed an individual value is from the average of all observations in a data set. So, if a climate expert describes a heavy rain event as a “5-sigma event,” s/he is talking about rainfall so extreme that it was 5 standard deviations away from the average rainfall for that location—way out at the tail end of the range of all values that have ever been observed. .

Another way of characterizing an extreme event is by describing the probability of occurrence in a given span of time. Based on historical observations, experts to estimate the range of all possible events that we would eventually expect to observe if our data record was long enough. From this range of all possible values, they can pinpoint how frequently a particular value would be expected to recur within a given amount of time. For example, 100-year event means an event is so extreme that it has only a 1 percent chance (1 divided by 100) of happening in any given year. A thousand-year event has a 0.1 percent chance of happening in any single year (1 divided by 1,000). .

 by global warming. However, over the past decade, that climate change due to global warming has made many extreme events more likely, more intense, longer-lasting, or larger in scale than they would have been without it. For many of the events that have been studied, global warming has been identified as the primary driver of the event, not just a supporting player. And a number of recent studies have concluded that certain heat-related extreme events would not have been possible without human-caused global warming. Learn more   and  .

is the science of figuring out what caused a given extreme weather or climate event, and weighting the relative influence of global warming versus natural variability. The biggest collection of research dedicated to understanding the causes of extreme events is published annually in a special issue of the Bulletin of the American Meteorological Society. The most recent edition of the report, , was the eighth in the series. (The report covering a selection of events from 2019 is soon to be released). Together, these eight reports have documented 168 attribution studies, 73 percent of which identified a substantial link between an extreme event and human-caused climate change, whereas 27 percent did not. To learn more, go   and 

]

Today’s warming is occurring much more quickly than previous interglacial episodes. In transitions from an ice age to an interglacial, it took 5,000–10,000 years for the temperature to rise between 5 and 9° Fahrenheit (3–5° Celsius). Humans could witness the same amount of global warming within the next 80 years if we continue emitting heat-trapping gases at today’s rate. ]

Finally, if we cause our world to warm by 2.7°F (1.5°C) or more compared to the temperatures before the start of the Industrial Revolution, scientists warn that there will be harmful repercussions for human health, the economy, infrastructure, and agriculture and natural resources. ] The greater the warming above that threshold, the more widespread and severe the impacts are likely to be. Human and natural systems that cannot adapt quickly enough may be overwhelmed.

from year to year. In a geological context, a global-scale warming of 1.8°F (1°C) in less than 150 years is an unusually large temperature change in a relatively short span of time.

It's also important to recognize that Earth is not warming uniformly, nor is it expected to. Middle and high latitudes in general will warm more than the tropics, and land surface temperatures will rise more than ocean temperatures. Over the long term, land masses at the latitude of the United States are expected to warm much more than the global average.  ] If global warming continues at an increasing rate, in several decades the world is likely to be warmer than it's been for over a million years, with unpredictable consequences for humans and the natural resources we depend on.

] ]
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]  ]  ]

In terms of biodiversity, adaptable species with wide geographic ranges—such as white-tailed deer and feral hogs—are likely to continue to thrive. But those species that depend on particular habitats—polar and alpine species, coral reefs, coldwater fishes—are vulnerable, as are the communities that depend on them culturally and economically. ] According to the Fourth National Climate Assessment, “[S]pecies, including many iconic species, may disappear from regions where they have been prevalent or become extinct, altering some regions so much that their mix of plant and animal life will become almost unrecognizable.” ]

Food and forage production will decline in agricultural regions experiencing increased frequency and duration of drought. Even without drought, higher temperatures will increase evaporation of soil moisture, increasing crop stress and water demand—further stressing U.S. surface and groundwater supplies used for irrigation. And even with irrigation, many commodity crops are likely to experience declines in average yield as temperatures rise beyond their preferred heat tolerance range. Milder winters and shifts in precipitation are likely to increase the incidence of pests and diseases for crops and livestock, while extreme heat—especially nighttime heat—will reduce livestock productivity. Impacts will vary from region to region, depending on the extent of warming and the level of adaptation. ]

.

] and the trend is likely to continue as many extreme events become more frequent and severe. The economic impacts of extreme events include not just the direct damages, but also the loss of productivity and interruption of essential services and supply chains that can reach deep into the national economy. ]

In many parts of the country, existing infrastructure—septic and stormwater systems, roads, bridges, the energy grid—was not designed to cope with current and future sea level and climate extremes, and current levels of investment aren’t enough to cover necessary repairs and upgrades. ]  ]

Beyond extreme events, human-caused climate change is likely to disrupt many sectors of the U.S. economy and the communities that depend on them, including commercial and recreational fisheries, tourism and recreation, and agriculture. ]  ]  ]

In the short term, farmers in some regions may benefit from the earlier onset of spring and from a longer warm season that is suitable for growing crops. Also, studies show that, up to a certain point, crops and other plants grow better in the presence of higher carbon dioxide levels and seem to be more drought-tolerant. ] But this benefit is a two-edged sword: weeds, many invasive plant species, and insect pests will also thrive in a warmer world. Water availability will be impacted in drier agricultural areas that need irrigation. At some point, the benefits to crops of increased carbon dioxide will likely be overwhelmed by the negative impacts of heat stress and drought.

In the long term, shipping commerce will benefit from the opening of the Northwest Passage for longer periods of the year due to the loss of Arctic sea ice. However, in the long run, if a "business as usual" approach to emitting heat-trapping gases is maintained at the present rate, or faster, then the negative costs and impacts of global warming are very likely to far outweigh the benefits over the course of this century, with increased potential for catastrophic impacts from more extreme events. ] In part, this is because any substantial change, whether warmer or colder, would challenge the societal infrastructure that has developed under the current climate.

]

If all human emissions of heat-trapping gases were to stop today, Earth’s temperature would continue to rise for a few decades as ocean currents bring excess heat stored in the deep ocean back to the surface. Once this excess heat radiated out to space, Earth’s temperature would stabilize. Experts think the additional warming from this “hidden” heat is unlikely to exceed 0.9° Fahrenheit (0.5°Celsius). ] With no further human influence, natural processes would begin to slowly remove the excess carbon dioxide from the atmosphere, and global temperatures would gradually begin to decline.

It’s true that without dramatic action in the next couple of decades, we are unlikely to keep global warming in this century below 2.7° Fahrenheit (1.5° Celsius) compared to pre-industrial temperatures—a threshold that experts say offers a lower risk of serious negative impacts. ] But the more we overshoot that threshold, the more serious and widespread the negative impacts will be, which means that it is never “too late” to take action.

it is likely many strategies working together will be needed. Generally speaking, here are some examples of mitigation strategies we can use to slow or stop the human-caused global warming ( ):

techniques.

Note that NOAA doesn’t advocate for or against particular climate policies. Instead, NOAA’s role is to provide data and scientific information about climate, including how it has changed and is likely to change in the future depending on different climate policies or actions society may or may not take. Learn more  and .

):

Note that NOAA doesn’t advocate for or against particular climate policies. Instead, NOAA’s role is to provide data and scientific information about climate, including how it has changed and is likely to change in the future depending on different climate policies or actions society may or may not take. Learn more  and .

NOAA is helping to improve the nation’s resilience to changes in climate and weather. Specifically, NOAA is working to…

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• ENVIRONMENT

How global warming is disrupting life on Earth

The signs of global warming are everywhere, and are more complex than just climbing temperatures.

Our planet is getting hotter. Since the Industrial Revolution—an event that spurred the use of fossil fuels in everything from power plants to transportation—Earth has warmed by 1 degree Celsius, about 2 degrees Fahrenheit.  

That may sound insignificant, but 2023 was the hottest year on record , and all 10 of the hottest years on record have occurred in the past decade.  

Global warming and climate change are often used interchangeably as synonyms, but scientists prefer to use “climate change” when describing the complex shifts now affecting our planet’s weather and climate systems.  

Climate change encompasses not only rising average temperatures but also natural disasters, shifting wildlife habitats, rising seas , and a range of other impacts. All of these changes are emerging as humans continue to add heat-trapping greenhouse gases , like carbon dioxide and methane, to the atmosphere.

What causes global warming?

When fossil fuel emissions are pumped into the atmosphere, they change the chemistry of our atmosphere, allowing sunlight to reach the Earth but preventing heat from being released into space. This keeps Earth warm, like a greenhouse, and this warming is known as the greenhouse effect .  

Carbon dioxide is the most commonly found greenhouse gas and about 75 percent of all the climate warming pollution in the atmosphere. This gas is a product of producing and burning oil, gas, and coal. About a quarter of Carbon dioxide also results from land cleared for timber or agriculture.  

Methane is another common greenhouse gas. Although it makes up only about 16 percent of emissions, it's roughly 25 times more potent than carbon dioxide and dissipates more quickly. That means methane can cause a large spark in warming, but ending methane pollution can also quickly limit the amount of atmospheric warming. Sources of this gas include agriculture (mostly livestock), leaks from oil and gas production, and waste from landfills.  

What are the effects of global warming?  

One of the most concerning impacts of global warming is the effect warmer temperatures will have on Earth's polar regions and mountain glaciers. The Arctic is warming four times faster than the rest of the planet. This warming reduces critical ice habitat and it disrupts the flow of the jet stream, creating more unpredictable weather patterns around the globe.  

( Learn more about the jet stream. )

A warmer planet doesn't just raise temperatures. Precipitation is becoming more extreme as the planet heats. For every degree your thermometer rises, the air holds about seven percent more moisture. This increase in moisture in the atmosphere can produce flash floods, more destructive hurricanes, and even paradoxically, stronger snow storms.  

The world's leading scientists regularly gather to review the latest research on how the planet is changing. The results of this review is synthesized in regularly published reports known as the Intergovernmental Panel on Climate Change (IPCC) reports.  

A recent report outlines how disruptive a global rise in temperature can be:

• Coral reefs are now a highly endangered ecosystem. When corals face environmental stress, such as high heat, they expel their colorful algae and turn a ghostly white, an effect known as coral bleaching . In this weakened state, they more easily die.  
• Trees are increasingly dying from drought , and this mass mortality is reshaping forest ecosystems.
• Rising temperatures and changing precipitation patterns are making wildfires more common and more widespread. Research shows they're even moving into the eastern U.S. where fires have historically been less common.
• Hurricanes are growing more destructive and dumping more rain, an effect that will result in more damage. Some scientists say we even need to be preparing for Cat 6 storms . (The current ranking system ends at Cat 5.)

How can we limit global warming?  

Limiting the rising in global warming is theoretically achievable, but politically, socially, and economically difficult.  

Those same sources of greenhouse gas emissions must be limited to reduce warming. For example, oil and gas used to generate electricity or power industrial manufacturing will need to be replaced by net zero emission technology like wind and solar power. Transportation, another major source of emissions, will need to integrate more electric vehicles, public transportation, and innovative urban design, such as safe bike lanes and walkable cities.  

( Learn more about solutions to limit global warming. )

One global warming solution that was once considered far fetched is now being taken more seriously: geoengineering. This type of technology relies on manipulating the Earth's atmosphere to physically block the warming rays of the sun or by sucking carbon dioxide straight out of the sky.

Restoring nature may also help limit warming. Trees, oceans, wetlands, and other ecosystems help absorb excess carbon—but when they're lost, so too is their potential to fight climate change.  

Ultimately, we'll need to adapt to warming temperatures, building homes to withstand sea level rise for example, or more efficiently cooling homes during heat waves.  

Related Topics

• CLIMATE CHANGE
• ENVIRONMENT AND CONSERVATION
• POLAR REGIONS

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global warming summary

Learn about the causes and effects of global warming.

global warming , Increase in the global average surface temperature resulting from enhancement of the greenhouse effect, primarily by air pollution . In 2007 the UN Intergovernmental Panel on Climate Change forecast that by 2100 global average surface temperatures would increase 3.2–7.2 °F (1.8–4.0 °C), depending on a range of scenarios for greenhouse gas emissions, and stated that it was now 90 percent certain that most of the warming observed over the previous half century could be attributed to greenhouse gas emissions produced by human activities (i.e., industrial processes and transportation). Many scientists predict that such an increase in temperature would cause polar ice caps and mountain glaciers to melt rapidly, significantly raising the levels of coastal waters, and would produce new patterns and extremes of drought and rainfall, seriously disrupting food production in certain regions. Other scientists maintain that such predictions are overstated. The 1992 Earth Summit and the 1997 Kyoto Protocol to the United Nations Framework Convention on Climate Change attempted to address the issue of global warming, but in both cases the efforts were hindered by conflicting national economic agendas and disputes between developed and developing nations over the cost and consequences of reducing emissions of greenhouse gases.

Climate Matters • November 25, 2020

New Presentation: Our Changing Climate

Key concepts:.

Climate Central unveils Our Changing Climate —an informative and customizable climate change presentation that meteorologists, journalists, and others can use for educational outreach and/or a personal Climate 101 tool.

The presentation follows a ”Simple, Serious, Solvable” framework, inspired by climate scientist Scott Denning. This allows the presenter to comfortably explain, and the viewers to easily understand, the causes (Simple), impacts (Serious), and solutions (Solvable) of climate change. 

Our Changing Climate is a revamped version of our 2016 climate presentation, and includes the following updates and features:

Up-to-date graphics and topics

Local data and graphics

Fully editable slides (add, remove, customize)

Presenter notes, background information, and references for each slide

Supplementary and bonus slides

Download Outline (PDF, 110KB)

Download Full Presentation (PPT, 148MB)

Updated: April 2021

Climate Central is presenting a new outreach and education resource for meteorologists, journalists, and others—a climate change presentation, Our Changing Climate . This 55-slide presentation is a guide through the basics of climate change, outlining its causes, impacts, and solutions. This climate change overview is unique because it includes an array of local graphics from our ever-expanding media library. By providing these local angles, the presenter can demonstrate that climate change is not only happening at a global-scale, but in our backyards.

This presentation was designed to support your climate change storytelling, but can also double as a great Climate 101 tool for journalists or educators who want to understand climate change better. Every slide contains main points along with background information, so people that are interested can learn at their own pace or utilize graphics for their own content. 

In addition to those features, it follows the “Simple, Serious, Solvable” framework inspired by Scott Denning, a climate scientist and professor of atmospheric science at Colorado State University (and a good friend of the program). These three S’s help create the presentation storyline and outline the causes (Simple), impacts (Serious), and solutions (Solvable) of climate change. 

Simple. It is simple—burning fossil fuels is heating up the Earth. This section outlines the well-understood science that goes back to the 1800s, presenting local and global evidence that our climate is warming due to human activities.

Serious. More extreme weather, rising sea levels, and increased health and economic risks—the consequences of climate change. In this section, well, we get serious. Climate change impacts are already being felt around the world, and they will continue to intensify until we cut greenhouse gas emissions. 

Solvable. With such a daunting crisis like climate change, it is easy to get wrapped up in the negative impacts. This section explains how we can curb climate change and lists the main pathways and solutions to achieving this goal. 

With the rollout of our new climate change presentation, we at Climate Central would value any feedback on this presentation. Feel free to reach out to us about how the presentation worked for you, how your audience reacted, or any ideas or topics you would like to see included. 

ACKNOWLEDGMENTS & SPECIAL THANKS

Climate Central would like to acknowledge Paul Gross at WDIV-TV in Detroit and the AMS Station Science Committee for the original version of the climate presentation, Climate Change Outreach Presentation , that was created in 2016. We would also like to give special thanks to Scott Denning, professor of atmospheric science at Colorado State University and a member of our NSF advisory board, for allowing us to use this “Simple, Serious, Solvable” framework in this presentation resource.

SUPPORTING MULTIMEDIA

5 things you should know about the greenhouse gases warming the planet

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News stories about the climate crisis often contain mentions of greenhouse gases, and the greenhouse effect. Whilst most will find the analogy easy to understand, what exactly are these gases, and why are they contributing to the warming of the Earth?

1. What is the greenhouse effect?

In a greenhouse, sunlight enters, and heat is retained. The greenhouse effect describes a similar phenomenon on a planetary scale but, instead of the glass of a greenhouse,  certain gases are increasingly raising global temperatures.

The surface of the Earth absorbs just under half of the sun’s energy, while the atmosphere absorbs 23 per cent, and the rest is reflected back into space. Natural processes ensure that the amount of incoming and outgoing energy is equal, keeping the planet’s temperature stable.

However, human activity is resulting in the increased emission of so-called greenhouse gases (GHGs) which, unlike other atmospheric gases such as oxygen and nitrogen, becomes trapped in the atmosphere, unable to escape the planet. This energy returns to the surface, where it is reabsorbed.

Because more energy enters than exits the planet, surface temperatures increase until a new balance is achieved. 

2. Why does the warming matter?

This temperature increase has long-term, adverse effects on the climate, and affects a myriad of natural systems. Effects include increases in the frequency and intensity of extreme weather events – including flooding, droughts, wildfires and hurricanes – that affect millions of people and cause trillions in economic losses.

“Human-caused greenhouse gas emissions endanger human and environmental health,” says Mark Radka, Chief of the UN Environment Programme’s ( UNEP ) Energy and Climate Branch. “And the impacts will become more widespread and severe without strong climate action.”

GHG emissions are critical to understanding and addressing the climate crisis: despite an initial dip due to COVID-19 , the latest UNEP Emissions Gap Report shows a rebound, and forecasts a disastrous global temperature rise of at least 2.7 degrees this century, unless countries make much greater efforts to reduce emissions.

The report found that GHG emissions need to be halved by 2030, if we are to limit global warming to 1.5°C compared to pre-industrial levels by the end of the century.

3. What are the major greenhouse gases?

Water vapour is the biggest overall contributor to the greenhouse effect. However, almost all the water vapour in the atmosphere comes from natural processes.

Carbon dioxide (CO2), methane and nitrous oxide are the major GHGs to worry about. CO2 stays in the atmosphere for up to 1,000 years, methane for around a decade, and nitrous oxide for approximately 120 years.

Measured over a 20-year period, methane is 80 times more potent than CO2 in causing global warming, while nitrous oxide is 280 times more potent.

4. How is human activity producing these greenhouse gases?

Coal, oil, and natural gas continue to power many parts of the world. Carbon is the main element in these fuels and, when they’re burned to generate electricity, power transportation, or provide heat, they produce CO2.

Oil and gas extraction, coal mining, and waste landfills account for 55 per cent of human-caused methane emissions. Approximately 32 per cent of human-caused methane emissions are attributable to cows, sheep and other ruminants that ferment food in their stomachs. Manure decomposition is another agricultural source of the gas, as is rice cultivation. 

Human-caused nitrous oxide emissions largely arise from agriculture practices. Bacteria in soil and water naturally convert nitrogen into nitrous oxide, but fertilizer use and run-off add to this process by putting more nitrogen into the environment.

Fluorinated gases – such as hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride – are GHGs that do not occur naturally. Hydrofluorocarbons are refrigerants used as alternatives to chlorofluorocarbons (CFCs), which, having depleted the ozone layer,were phased out thanks to the Montreal Protocol. The others have industrial and commercial uses.

While fluorinated gases are far less prevalent than other GHGs and do not deplete the ozone layer like CFCs, they are still very powerful. Over a 20-year period, the global warming potential of some fluorinated gases is up to 16,300 times greater than that of CO2.

5. What can we do to reduce GHG emissions?

Shifting to renewable energy, putting a price on carbon, and phasing out coal are all important elements in reducing GHG emissions. Ultimately, stronger emission-reduction targets are necessary for the preservation of long-term human and environmental health.

“We need to implement strong policies that back the raised ambitions,” says Mr. Radka. “We cannot continue down the same path and expect better results. Action is needed now.”

During COP26, the European Union and the United States launched the Global Methane Pledge, which will see over 100 countries aim to reduce 30 per cent of methane emissions in the fuel, agriculture and waste sectors by 2030.

Despite the challenges, there is reason to be positive. From 2010 to 2021, policies were put in place  to lower annual emissions by 11 gigatons by 2030 compared to what would have otherwise happened. Individuals can also join the UN’s #ActNow campaign for ideas to take climate-positive actions.

By making choices that have less harmful effects on the environment, everyone can be a part of the solution and influence change. Speaking up is one way to multiply impact and create change on a much bigger scale.  

UNEP’s role in reducing GHGs

• UNEP has outlined its six-sector solution, which can reduce 29–32 gigatons of carbon dioxide by 2030 to meet the 1.5°C warming limit. The six sectors identified are: energy; industry; agricultureand food; forests andland use; transport; and buildings and cities.
• UNEP also maintains an online “Climate Note,” a tool that visualizes the changing state of the climate with a baseline of 1990.
• Through its other multilateral environmental agreements and reports, UNEP raises awareness and advocates for effective environmental action. UNEP will continue to work closely with its 193 Member States and other stakeholders to set the environmental agenda and advocate for a drastic reduction in GHG emissions.
• greenhouse gas emissions

Global warming, explained

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The ‘Conclusion’ confirms that global warming is the major challenge for our global society. There is very little doubt that global warming will change our climate in the next century. So what are the solutions to global warming? First, there must be an international political solution. Second, funding for developing cheap and clean energy production must be increased, as all economic development is based on increasing energy usage. We must not pin all our hopes on global politics and clean energy technology, so we must prepare for the worst and adapt. If implemented now, a lot of the costs and damage that could be caused by changing climate can be mitigated.

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global warming

Introduction.

Greenhouse Effect

To understand global warming, it helps to understand the greenhouse effect . A greenhouse is a glass house where plants grow. Glass lets light in and keeps heat from escaping. This trapped heat keeps the plants warm even when it is cold outside.

Likewise, Earth’s atmosphere traps energy from the Sun. Carbon dioxide and other gases—called greenhouse gases—in the air do this trapping. Without these gases too much heat would go back into space, and living things could not survive. However, as more greenhouse gases get into the air, they also trap more heat. This leads to global warming.

For much of Earth’s history, greenhouse gases were not a problem. This situation changed as people came to depend on fossil fuels (oil, gas, and coal). People burn fossil fuels to power factories, run cars, produce electricity, and heat houses. As fossil fuels burn, they release carbon dioxide into the atmosphere.

Also, people have cut down many forests. Trees use carbon dioxide when they make their own food. Fewer trees mean that less carbon dioxide is being taken out of the atmosphere.

Reasons for Concern

Scientists cannot tell how warm Earth may get over time. Some guess an increase between 3.2° F and 7.2° F (1.8° C and 4° C) by the year 2100. The warmer weather could harm living things. It also could cause polar ice caps to melt. This would cause sea levels to rise. Plants, animals, and buildings along coastlines would be in danger.

Stopping Global Warming

Global warming is a worldwide concern. Governments are trying to find ways to limit the amount of greenhouse gases put into the air. Individual people can help by driving less. They also can save energy by turning off unneeded lights and other electrical devices.

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Global Warming

And how it’s killing us from our insides out

We’ve all heard about Global Warming. We get that it’s bad, but really? How is the world getting a little warmer bad anyway?

What is Global Warming? Agriculture Polar Melting Sea Level Rise Economic

What is Global Warming?

Global Warming is the gradual heating of Earth's surface, oceans and atmosphere. Scientists have documented the rise in average temperatures worldwide since the late 1800s. Earth's average temperature has risen by 1.4 degrees Fahrenheit (0.8 degrees Celsius) over the past century, according to the Environmental Protection Agency (EPA). Temperatures are projected to rise another 2 to 11.5 degrees Fahrenheit (1.133 to 6.42 degrees Celsius) over the next 100 years.

Agriculture Problems

All agriculture depends also on steady water supplies, and Global Warming is likely to disrupt those supplies through floods and droughts. It has been suggested that higher latitudes – Siberia, for example – may become productive due to Global Warming, but the soil in Arctic and bordering territories is very poor, and the amount of sunlight reaching the ground in summer will not change because it is governed by the tilt of the earth. Agriculture can also be disrupted by wildfires and changes in seasonal periodicity, which is already taking place, and changes to grasslands and water supplies could impact grazing and welfare of domestic livestock. Increased warming may also have a greater effect on countries whose climate is already near or at a temperature limit over which yields reduce or crops fail – in the tropics or sub-Sahara, for example.

Polar Melting

While the opening of a year-round ice free Arctic passage between the Atlantic and Pacific oceans would confer some commercial benefits, these are considerably outweighed by the negatives. Detrimental effects include loss of polar bear habitat and increased mobile ice hazards to shipping. The loss of ice albedo (the reflection of heat), causing the ocean to absorb more heat, is also a positive feedback; the warming waters increase glacier and Greenland ice cap melt, as well as raising the temperature of Arctic tundra, which then releases methane, a very potent greenhouse gas (methane is also released from the sea-bed, where it is trapped in ice-crystals called clathrates). Melting of the Antarctic ice shelves is predicted to add further to sea-level rise with no benefits accruing.

Sea Level Rise

Many parts of the world are low-lying and will be severely affected by modest sea rises. Rice paddies are being inundated with salt water, which destroys the crops. Seawater is contaminating rivers as it mixes with fresh water further upstream, and aquifers are becoming polluted. Given that the IPCC did not include melt-water from the Greenland and Antarctic ice-caps due to uncertainties at that time, estimates of sea-level rise are feared to considerably underestimate the scale of the problem. There are no proposed benefits to sea-level rise.

Islands being destroyed by sea level rise

Economic Problems

The economic impacts of climate change may be catastrophic, while there have been very few benefits projected at all. The Stern report made clear the overall pattern of economic distress, and while the specific numbers may be contested, the costs of climate change were far in excess of the costs of preventing it. Certain scenarios projected in the IPCC AR4 report would witness massive migration as low-lying countries were flooded. Disruptions to global trade, transport, energy supplies and labour markets, banking and finance, investment and insurance, would all wreak havoc on the stability of both developed and developing nations. Markets would endure increased volatility and institutional investors such as pension funds and insurance companies would experience considerable difficulty.

Developing countries, some of which are already embroiled in military conflict, may be drawn into larger and more protracted disputes over water, energy supplies or food, all of which may disrupt economic growth at a time when developing countries are beset by more egregious manifestations of climate change. It is widely accepted that the detrimental effects of climate change will be visited largely on the countries least equipped to adapt, socially or economically.

So what can we do to help?

• Plant trees.
• Recycle more.
• Use less water
• Always turn out the lights when you leave a room.

Learn More About Global Warming And How To Stop It

http://planetsave.com/2008/11/28/five-ways-to-prevent-global-warming-that-big-media-wont-tell-you/

http://globalwarming-facts.info/50-tips/?single page=1

https://www.nrdc.org/stories/how-you-can-stop-global-warming

http://www.conserve-energy-future.com/StopGlobalWarming.php

http://www.ucsusa.org/our-work/global-warming/solutions/global-warming-solutions-reduce-emissions#.WEDoebIrIq

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• Revealed: The 11 slides that finally convinced Boris Johnson about global warming

Multiple Authors

A scientific briefing that UK prime minister Boris Johnson says changed his mind about global warming has been made public for the first time, following a freedom-of-information (FOI) request by Carbon Brief.

Last year, on the eve of the UK hosting COP26 in Glasgow, Johnson described tackling climate change as the country’s “ number one international priority ”. He also published a net-zero strategy and told other countries at the UN General Assembly to “ grow up ” when it comes to global warming.

However, just a few years earlier, Johnson was publicly doubting established climate science. For example, in a Daily Telegraph column published in 2015 he claimed unusual winter heat had “ nothing to do with global warming ”. And, in 2013, he said he had an “ open mind ” to the idea that the Earth was heading for a mini ice-age.

Last year, acknowledging his past climate scepticism, Johnson told journalists that he had now changed his mind, largely due to a scientific briefing he received shortly after becoming prime minister in 2019.

Johnson admitted he had been on a “road to Damascus” when it comes to climate science:

“I got them [government scientists] to run through it all and, if you look at the almost vertical kink upward in the temperature graph, the anthropogenic climate change, it’s very hard to dispute. That was a very important moment for me.”

The Sunday Times later reported that this briefing had been given by Sir Patrick Vallance , the government’s chief scientific advisor, and, according to one of the prime minister’s close allies, it “had a huge impact”. Using a FOI request submitted to the UK’s Government Office for Science (“GO-Science”), Carbon Brief has now obtained the contents of this pivotal scientific briefing, which took place on 28 January 2020 inside 10 Downing Street.

Below, Carbon Brief reveals the 11 slides that were used to “teach” Johnson about climate change, as well as the email correspondence exchanged between leading scientists and advisors as they prepared the prime minister’s briefing. [ Jump straight to see the 11 slides used in the presentation. ]

The emails suggest that some No 10 advisors were suspicious of important aspects of climate science – for example, asking whether UN’s Intergovernmental Panel on Climate Change (IPCC) reports were “worth taking note of”.

Email correspondence

The exchange of emails begins on 23 January 2020 when someone in the office of the  government’s chief scientific adviser , Sir Patrick Vallance, emails Met Office chief scientist Prof Stephen Belcher and Prof Gideon Henderson , the chief scientific adviser at the Department of Environment, Food and Rural Affairs (Defra). (See Carbon Brief’s in-depth interview with Belcher published in April 2018.)

The message describes plans for a climate change-themed “teach in” involving the two scientists which will be attended by a selection of No 10 staff, including some redacted names and “SpAds” (special advisors). Munira Mirza has been the director of the “No10 policy unit”, which is referred to in the email, since Johnson became prime minister in 2019. (See the note at the end of the article about the reasoning given by GO-Science for redacting some names.)

Also copied into the email is Dr Stuart Wainwright , who is the director of GO-Science and, therefore, works under Vallance.

Henderson responds, noting that “we’ll need to prioritise this when we hear the time”.

The next day, an email is sent “on behalf of” Dominic Cummings , then the prime minister’s chief adviser, inviting the scientists to an event on 28 January in the Cabinet Room at No 10.

Shortly afterwards, Wainwright contacts Belcher outlining what they want to cover in the briefing. The plan focuses on what could be described as the basics of climate science, including evidence for human-caused climate change and the formation of scientific consensus. There is a notable focus on “uncertainty”. 

This is followed by an email from Vallance’s office to a number of people, including Cummings, reiterating these three priority areas and indicating that Belcher has “previously discussed an idea of how to structure the session” with the chief scientific adviser. 

They indicate that Belcher should “liaise with academic colleagues on pulling something together”, to which he replies: “Will do.” (The Met Office has confirmed to Carbon Brief that its senior climate scientists Prof Richard Betts and Prof Peter Stott both assisted Belcher in preparing for the briefing.)

An email from Wainwright follows explaining that the planned climate change session is “part of a broader set of teach in’s [sic] on various policy, economic, science aspects that will inform advice to the PM”. 

At this point, Johnson had been in No 10 for six months, after taking over as Conservative leader in July 2019 and winning a general election in December.

The next email is from Chris Pook , a deputy director in GO-Science working under Wainwright and Vallance. 

He invites Richard Barker , head of energy and environment at National Physical Laboratory , to participate in the meeting as an expert, saying they need someone who can discuss uncertainty in climate measurements and help understand “what this means for decision-making”. 

Two days later, on 26 January, Belcher emails the government scientists explaining that he has been working on a series of slides. Topics he mentions include the “need for quantitative advice on carbon budgets to achieve targets” and “current challenges” on tipping points and future impacts and extremes . 

He also says they could discuss the concept of scientific peer review, the Intergovernmental Panel on Climate Change (IPCC) and Berkeley Earth , a US-based institution that analyses land temperature data, “as an example of a new group coming in as independent tests”.

Additionally, he suggests a selection of five experts who could contribute to the session. The names of all but one – Baroness Brown , chair of the Climate Change Committee’s (CCC) adaptation committee – are redacted. One is proposed with the caveat that “she has done lots of media work, quite campaigning”. Another is described as an “excellent communicator on impacts”. A further suggestion comes with the remark: “I appreciate Stuart you thought she might appear too close? She is excellent.”

On 27 January, the day before the meeting, Vallance’s office contacts Belcher confirming that Barker and another individual whose name has been redacted will be invited to the event. They mention that they have been delayed due to “trying to juggle the response to Wuhan coronavirus”. (The first cases of Covid-19 in the UK were confirmed four days later.)

This email builds on the three priority areas previously mentioned, adding some more specific questions that No 10 would like the experts to address. These questions indicate a degree of scepticism about some of the key processes underlying climate science:

“No10 will want an answer to the question ‘why are the numbers so round’ eg 2050 target, and 1.5 degree etc. They also mentioned the IPCC reports and authors – ‘scientists or not’ – and are the reports worth taking note off!!! [sic]”

The “2050 target” likely refers to the UK’s legally binding goal for achieving net-zero emissions by 2050, established during the final days in office of Johnson’s predecessor, Theresa May. The mention of “1.5 degree” references the Paris Agreement’s stretch goal of limiting warming to 1.5C, which scientists think would limit some of the worst impacts of climate change.

The IPCC is a UN body that is regarded internationally as the authority on climate change. Its landmark assessment reports, assembled by hundreds of leading scientists every seven years or so, present comprehensive overviews of the state of knowledge on the topic.

This email is followed later that day by an internal message between GO-Science staff indicating that Belcher will lead the session and reiterating some key points from the session plan.

Again, this message highlights a focus on “what’s clear, what’s unsettled”, how scientific consensus is reached, “convenient numbers” and whether the IPCC process is “actually science”. 

It also asks: “…should we be worried that [the] range of uncertainty hasn’t changed (climate sensitivities)?” This references the point that estimates of climate sensitivity – a measure of how much the planet is expected to warm in response to rising CO2 levels – had not been narrowed for decades. While this is no longer the case following new research captured in last year’s IPCC sixth assessment report (AR6), this information had not yet been published at the time.

The final line of the email mentions a “Koonin red-teaming exercise” – presumably a reference to Dr Steven Koonin , a US physicist who has worked for both BP and the Obama administration, and who has more recently been accused of downplaying the severity of climate change.

During the years of the Trump administration in the US, Koonin advocated for a “ red team ” methodology to “test assumptions and analyses, identify risks, and reduce – or at least understand – uncertainties” around climate science. The approach saw some support within the Trump administration, but was dismissed by other scientists as inappropriate for assessing climate science. No such exercise ever ended up taking place.

It is notable that Dominic Cummings has also been a prominent supporter of the “red-team” approach in various fields as a means of combating what he describes as “groupthink and normal cognitive biases”. (Carbon Brief has approached Cummings for comment, but, upon publication, had not received a response.)

As the meeting approaches, the participants arrange a 45-minute “pre-meet” before heading to No 10. At this point, Belcher, Henderson, Vallance and Barker are listed as attending the meeting, along with one more redacted name. Another redacted name is unable to come as “she is in France”.

On the morning of 28 January, Belcher sends over his slides – which he describes as “reasonably vanilla” – to “guide discussion later today”. Among other things, he emphasises that the “goal is to stabilise climate, which requires net-zero emissions”. He asks for feedback from the others.

Henderson responds with some last-minute changes to the presentation. He notes that it largely misses out impacts of sea-level rise, including on the UK and its flood defences, something that is “perhaps more important than arctic [sic] sea ice for HMG [the government]”. He adds that, “personally, I would put more focus on C cycle [carbon cycle] as cause of problem, important feedbacks, and the bit we need to act on”.

There is another, lengthy, response to Belcher from a redacted email address. It suggests adding a chart showing the long-term record of carbon dioxide (CO2), as well as various climate impacts taken from the IPCC, including huge losses for coral reefs, impacts on crop production and increased spread of various diseases. The writer stresses that “it may be worth pointing out that to achieve 1.5C (and perhaps 2C) requires net *negative* emissions ”.

They also attach the chart below as an example of one that could be added to the presentation, noting that a “striking thing to show” would be “the long-term record of CO2”. They note that they cannot find a suitable chart from the IPCC’s fifth assessment report (AR5), published in 2013, and so include one from the fourth assessment (AR4), from 2007. The emailer notes that “it’s out of date, of course – CO2 is now up to 400 ppm [parts per million]”.

The chart, or a more recent version of it, does not make it into the final presentation.

Barker also responds to Belcher’s call for suggestions with a “rather basic question” around the conclusion they want to present to No 10:

“My assumption is that we want this meeting to establish the big opportunity for us to take a big step forward.”

While Belcher says he will leave Vallance to “comment on the overall purpose of the meeting”, there is no email from the chief scientific adviser clarifying this point in the released documents. His office does note again at this point that they are “currently quite immersed in coronavirus”.

Finally, as the meeting approaches, the final slides are sent out to GO-Science with a request for 15 hard copies to be printed, possibly indicating the final number of attendees at the event.

(Carbon Brief has learned that Boris Johnson received at least one further science briefing on climate change following this January 2020 presentation. In March 2021, for example, he was specifically briefed about, among other topics, the projected climate impacts at 2C and 4C of global warming. The information about these impacts was prepared by Prof Richard Betts from the Met Office and the University of Exeter using findings from the EU-funded HELIX project . Prof Betts also provided UK examples from the Technical Report of the Third UK Climate Change Risk Assessment, often known as CCRA3 . Carbon Brief also understands that, even though Sir Patrick Vallance led the briefing at No 10 Downing Street on 28 January 2020, the 11 slides themselves were presented by Prof Belcher.)

S cience slides

Below, with explanation by Carbon Brief, are the 11 slides shown to the prime minister on the evening of 28 January 2020 in the Cabinet Room at No 10 Downing Street.

The three charts come from the Met Office Hadley Centre ’s Climate Dashboard – a website that brings together “the key indicators of climate change”. The site features graphs such as temperature change, sea level change and atmospheric CO2 change over time – drawing on data produced by “respected institutes and research groups around the world”. 

The graph in the top left is known as a Keeling Curve , and shows the increase in atmospheric CO2 levels over 1960-2020, measured in parts per million. The graph uses data from three sources – the Mauna Loa observation centre (blue), the National Oceanic and Atmospheric Administration (yellow) and the World Data Centre for Greenhouse Gases (red).

The graph in the bottom left shows the increase in global temperatures over 1850-2020, compared to the 1850-1900 average. The coloured lines indicate different datasets, including the Met Office HadCRUT (black) and the National Oceanic and Atmospheric Administration NOAAGlobalTemp (yellow).

The graph in the bottom right shows global sea level from 1993 to 2020, compared to the 1993-2010 average, in mm. The graph uses satellite datasets from organisations including the Commonwealth Scientific and Industrial Research Organisation (pink) and the National Aeronautics and Space Administration (light blue).

The map in the top right shows warming over 2009-19, compared to the 1961-90 average. The graph is similar in appearance to one used on the Met Office HadObs website .

The two charts on the left are from FAQ 10.1 in chapter 10 of the Working Group I report of the Intergovernmental Panel on Climate Change ’s (IPCC) fifth assessment report (AR5), published in 2013. This chapter focuses on “detection and attribution” of climate change.

The black lines show observations of global temperature since 1860, based on datasets including the Met Office HadCRUT4 dataset, while the red and blue lines show model results. The upper chart shows model simulations excluding the influence of human activity on global temperature results. Conversely, models in the lower chart include human influence on global temperatures. While the upper chart shows a clear departure between model runs and observations from the 1960s, the lower chart shows close agreement between the models and observations. This shows how “human forcing” plays a key role in observed temperature trends .

The map in the top right is a repeat of the one shown in the first slide. The map below it shows the equivalent data from climate model output (taken as an average across a number of models).

The large graphic was produced by the Met Office’s “Knowledge Integration” team – a group responsible for communicating climate science produced at the Met Office Hadley Centre to the general public and government. The map compares Arctic sea ice extent in 1980 and 2019. Meanwhile, the text states that over this time, September Arctic sea ice extent declined by 12% on average – resulting in an overall loss of almost 3.5m km2. 

The smaller insert is from the Met Office Climate Dashboard , and shows the decline in Arctic sea ice over 1980-2019, compared to the 1981-2020 average. The plot uses datasets from the Copernicus Climate Change Service , the Ocean and Sea Ice Satellite Application Facility and the National Snow and Ice Data Center .

The slide is titled “a tipping point”, but as a scientist in the email chain (with their name redacted) points out, the decline in Arctic sea ice is not strictly a tipping point. They write: “To me, that means sudden rapid change (through some unstable feedback) or irreversibility. There isn’t evidence for the former, as far as I know, and there are model studies that show that sea-ice comes back if you cool down the climate, so it’s not an irreversibility like ice-sheet loss could be.” For more on this, see the final section of Carbon Brief ’s tipping points explainer.

These figures were produced using the HadEX3 dataset . This dataset uses daily observations of both variables, taken at thousands of locations across the globe over 1901-2018, to produce “indices” of extreme temperature and precipitation.

The figures on the left show the change in extreme temperatures over 1950-2018. The top left map shows the regional pattern – where red indicates an increase in temperature extremes, blue indicates a decrease and grey denotes areas in which there was no data. The line plot below shows the number of days per year, over 1901-2018, that the global average temperature crossed a given threshold. The line plot compares the more recent dataset (HadEX3, black) with similar, older datasets.

The figures on the right use the same format for changes in extreme rainfall. The map shows the change in extreme rainfall over 1950-2018, where blue indicates an increase in rainfall extremes and brown indicates a decrease. The line plot shows the number of days per year global rainfall crossed a given threshold, for each year between 1901-2018.

The graphics show that while temperature extremes have increased across the globe since the 1970s, the signal for rainfall is less clear.

This slide features a range of images, maps and graphics showing the impacts of climate change. These are grouped under four subheadings – “flooding and sea level rise”, “heatwaves, health and disease”, “wildfires” and “biodiversity”.

For example, the blue graphic in the “flooding and sea level rise” category states that in the UK, “extended periods of extreme winter rainfall are now seven times more likely”. The graphic has previously been displayed on a section of the Met Office website detailing the impacts of climate change , both in the UK and globally. These pages have since been restructured.

This figure comes from the IPCC AR5 synthesis report , published in 2014. It shows the relationship between accumulating atmospheric CO2, rising global temperatures and climate change risks. (More up-to-date versions are available in the IPCC’s special report on 1.5C , published in 2018.)

Panel a) illustrates the five “Reasons For Concern” – also known as a “ burning embers ” chart – which summarise five key categories of risk around climate change. The colour of the shading – from white to purple – indicates an increasing level of risk with higher levels of warming.

Panel b) shows the relationship between cumulative CO2 emissions and global average surface temperature increase. The ellipses show expected total human-caused warming in 2100 expected from each level of cumulative emissions, plotted as a function of that total from 1870 to 2100. The filled black ellipses show observed emissions to 2005 and observed temperatures in the decade 2000-09, and the equivalent for 2017. The latter appears to have been added retrospectively to the IPCC chart for this presentation.

According to the credit on the image, this figure was created by Dr Erich Fischer , a senior scientist and lecturer in the Department of Environmental Systems Science at ETH Zurich . It was created using the Earth System Model Evaluation Tool (ESMValTool), which “allows for routine comparison of single or multiple models, either against predecessor versions or against observations”.

The figure shows observations (black lines) and climate model projections (coloured lines) of global average surface temperature change from 1850 to 2100. The left-hand chart shows the projections from the sixth Coupled Model Intercomparison Project (CMIP6) under five Shared Socioeconomic Pathways (SSPs). The right-hand chart shows the equivalent projections from CMIP5 using the Representative Concentration Pathways – the predecessors to CMIP6 and the SSPs, respectively. The right-hand chart has been flipped to allow a direct comparison between the two. The shading indicates the range in the projections under each scenario.

The figure on the left is a repeat of the sea level rise chart shown in the first slide.

The figure on the right is taken from the UK Climate Projections 2018 (UKCP18), produced by the Met Office. The charts on the left show UK average sea level rise from 2000 to 2100 under a scenario that likely keeps warming below 2C by 2100 ( RCP2.6 ) and a scenario of very high global emissions ( RCP8.5 ). The solid line and shaded regions represent the central estimate and ranges for each scenario, while the dashed lines indicate the overall range across RCP scenarios. The maps on the right show projected sea level rise in 2100 around the UK coastline under the central estimate of each RCP. The original figure (pdf) also includes an intermediate RCP4.5 scenario. All data are relative to a baseline period of 1981-2000.

This chart shows the Met Office decadal forecast for global temperatures, issued in January 2021. The forecast suggests that annual global average temperatures during 2021-25 are very likely to be between 0.91C and 1.61C above pre-industrial levels. In the chart, the black lines show observed data (from the Met Office, NASA and NOAA ), the blue shading shows the latest prediction, and the red shading shows previous predictions at five-year intervals starting from November 1960 and through to 2010. In addition, 22 model simulations from CMIP5 – that have not been initialised with observations – are shown in green. In all cases, the data is shown as rolling 12-month averages and the shading represents the probable range, such that the observations are expected to lie within the shading 90% of the time.

This figure was produced by Climate Action Tracker (CAT), an independent group that tracks government climate action towards the Paris Agreement goals. The chart was part of its December 2019 global update (pdf), although it does not appear to still be on the CAT website (there have been a number of updates since). The same chart is referenced in a June 2020 article by S&P Global . 

The chart shows the expected global temperature increase by the end of the century compared to pre-industrial levels implied by global emissions pathways in six scenarios: Baseline emissions, emissions compatible with warming of 1.5C and 2C, respectively, and the three scenarios resulting from aggregation of 32 country assessments: Pledges & targets, Current policies and an optimistic scenario. The shaded ranges indicate uncertainty in emissions projections and the dotted lines indicate median (50%) levels.

This table identifies a number of climate “ tipping points ” – thresholds beyond which a system can be pushed into a completely new state – and their potential impacts globally and for the UK. The table divides tipping points into three categories: the carbon cycle and other biogeochemical cycles, the cryosphere and sea level, and ocean/atmosphere circulation. The source of the table is not clear, though it could have been created specifically for the presentation.

All 38 emails released under the Freedom of Information Act 2000 by GO-Science to Carbon Brief can be viewed as a PDF . An earlier version of the presentation, which was discussed and shared in the emails, can also be viewed as a PDF , as well as the final version shown to the prime minister, also available as a PDF .

In responding to Carbon Brief’s FOI request, GO-Science provided the following explanation for why it delayed the release for more than a month to conduct a “public interest” test, as well as why some names in the emails were redacted:

“The requested information engaged Section 35(1)(a) – information related to the formulation of government policy; because of this we have carried out a public interest test. In this instance the information is in relation to factual background information and scientific consensus on climate science, provided to inform policy decisions regarding climate change. There is a high public interest in climate change-related policies, which have and will have a significant impact on the public. Given the public interest in transparency regarding the scientific information provided to government in this context, we have determined that it is in the public interest to disclose the information held, and we have not applied this exemption. We are refusing some of this information (redacted in the annexes) under: Section 40(2) – Personal information. We have withheld personal information if disclosure would breach one or more of the principles of the UK General Data Protection Regulation (UK GDPR) or Data Protection Act 2018 .

Carbon Brief also submitted an FOI request to the Cabinet Office asking for the same information about the 28 January 2020 briefing, but it responded – inaccurately, as GO-Science’s release of files proves – saying: “Searches of our records have not identified any information in scope of your request under the Act.”

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Report shows 2023 marked by record-breaking greenhouse gas levels, extreme heat and high sea levels

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Last year was another record year for carbon pollution, global temperatures, sea level rise and natural disasters, according to the latest international report on the world’s climate published Thursday. 

More than a dozen CU Boulder researchers contributed to the 34th annual State of the Climate report , led by scientists from the National Oceanic and Atmospheric Administration.

According to the report, the concentrations of Earth’s main greenhouse gases—carbon dioxide, methane and nitrous oxide—reached record highs last year. The increase from 2022 was one of the highest on record despite global commitments to cut emissions. 

“We are definitely not on the right path to limit global warming,” said Xin Lindsay Lan , the report’s co-author and a researcher at the Cooperative Institute for Research in Environmental Sciences (CIRES) at CU Boulder. “The planet is already warming rapidly, so it’s a critical time to reduce those greenhouse gas levels in the atmosphere. Instead, we are seeing a rapid increase.” 

The report, published in the Bulletin of the American Meteorological Society, also revealed that 2023 was the hottest year on record. Global mean sea level reached a record high for the 12th consecutive year. Heatwaves, storms and droughts also plagued the planet, while catastrophic wildfires pumped more emissions into the atmosphere.

CU Boulder Today sat down with Lan, who led the reporting of global greenhouse gas levels, to discuss the importance of emission reduction.

Xin Lindsay Lan

What do you make of the fact that emissions are still increasing? 

It is very concerning, because we are already at pretty high levels of global warming. The global average warming in the last decade is about 1.1°C above pre-industrial levels. Climate scientists like me are concerned that if global warming exceeds 1.5 °C, we could be facing some severe climate crises. So it’s very important that we try our best to limit greenhouse gas emissions and avoid crossing that threshold.

Many countries and entities have committed to cutting emissions. Are these efforts working?

Although there have been many efforts to cut emissions globally, our data shows that global greenhouse gas concentrations remain at very high levels. If emissions had decreased significantly, we would have seen a slowdown in the rise of global CO₂ levels, but there's no evidence of that. In fact, the increase in CO₂ from 2022 to 2023 was the fourth largest in recorded history.

Many countries pledged to reach net zero emission by around 2050, so we may see the global CO₂ emissions continue to increase at a fast pace until then.

Why is so much climate discussion focused on CO₂?

CO₂ is the most important greenhouse gas, and the main source of global carbon emissions is fossil fuel use. It contributes to about 66% of the global radiative energy increase, which directly leads to global warming.

While methane has a greater warming power than CO₂ per molecule, it has a shorter lifespan in the atmosphere after it’s released. When CO₂ is emitted, it can stay in the air for thousands of years, and it will continue to trap heat. A lot of the CO₂ in the air now has been there since the industrial era. Even if we stop emitting CO₂ today, we will continue to see warming effects from the CO₂ we’ve been putting into the air. 

In 2023 wildfires in Canada spewed 3 billion tons of CO₂—the equivalent of emissions from 647 million cars in a year. Did natural disasters contribute to the record high emissions?

The fires certainly contributed to our emissions last year. In addition to the fires and burning of fossil fuels, 2023 was a year of El Niño, which is a climate pattern characterized by warmer than normal ocean temperatures that release large amounts of heat into the atmosphere.

In warm years like 2023, a lot of forests may be under stress, which would reduce their CO₂ uptake. A warmer ocean may also absorb less CO₂ than normal.

What can society do?

One critical thing that we need is global collaboration. Greenhouse gasses, given their long lifespans in the atmosphere, do not respect state boundaries. We need to work together as a global community to reduce global greenhouse gas emissions.

What can individuals do? 

It’s important for individuals to believe they can make a difference in changing the course of climate change. One of the most critical things we can do is to limit our energy use, because the energy sector is the biggest source of greenhouse gas emissions. We can try to use renewable energy for our commutes to work. We can try to take public transportation when possible. We can reduce methane emissions by limiting food waste that goes to the landfill.

In addition to reducing our own carbon footprints, I would encourage individuals to vote and talk to your representative about your concerns on global warming. 

CU Boulder Today regularly publishes Q&As with our faculty members weighing in on news topics through the lens of their scholarly expertise and research/creative work. The responses here reflect the knowledge and interpretations of the expert and should not be considered the university position on the issue. All publication content is subject to edits for clarity, brevity and university style guidelines.

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‘Worst-Case’ Disaster for Antarctic Ice Looks Less Likely, Study Finds

Global warming is putting the continent’s ice at risk of destruction in many forms. But one especially calamitous scenario might be a less pressing concern, a new study found.

By Raymond Zhong

For almost a decade, climate scientists have been trying to get their heads around a particularly disastrous scenario for how West Antarctica’s gigantic ice sheet might break apart, bringing catastrophe to the world’s coasts.

It goes like this: Once enough of the ice sheet’s floating edges melt away, what remains are immense, sheer cliffs of ice facing the sea. These cliffs will be so tall and steep that they are unstable. Great chunks of ice start breaking away from them, exposing even taller, even more-unstable cliffs. Soon, these start crumbling too, and before long you have runaway collapse.

As all this ice tumbles into the ocean, and assuming that nations’ emissions of heat-trapping gases climb to extremely high levels, Antarctica could contribute more than a foot to worldwide sea-level rise before the end of the century.

This calamitous chain of events is still hypothetical, yet scientists have taken it seriously enough to include it as a “low-likelihood, high-impact” possibility in the United Nations’ latest assessment of future sea-level increase.

Now, though, a group of researchers has put forth evidence that the prospect may be more remote than previously thought. As humans burn fossil fuels and heat the planet, West Antarctica’s ice remains vulnerable to destruction in many forms. But this particular form, in which ice cliffs collapse one after the other, looks less likely, according to the scientists’ computer simulations.

“We’re not saying that we’re safe,” said Mathieu Morlighem, a professor of earth science at Dartmouth College who led the research. “The Antarctic ice sheet is going to disappear; this is going to happen. The question is how fast.”

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Global warming is affecting Antarctica, but image of flowers is from elsewhere | Fact check

The claim: image shows flowering plants in antarctica due to global warming.

A Sept. 21 Instagram post ( direct l i nk , archive link ) shows flowering plants growing on land with icebergs floating on water in the background.

"Flowers are now staring (sic) to bloom in Antarctica and experts say this is not good news," reads text around the image. "This would be the first evidence of accelerated ecosystem response in Antarctica that is directly associated as a consequence of global warming, according to Nicoletta Cannone, a professor of ecology at the University of Insubria."

The post garnered more than 2,000 likes in two weeks.

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Our rating: Partly false

While a 2022 study did find a global warming-related expansion in the range of two Antarctic flowering plants, the photo does not show those plant species. The photo is labeled as being captured in Greenland on a stock photo website.

Arctic – not Antarctic – flowers shown in the image

The photo in the social media post appears on the stock photo website Alamy , where it is labeled, "Iceberg floating in the water off the coast of Greenland. Flowers on the shore. Nature and landscapes of Greenland."

A spokesperson for the British Antarctic Survey told USA TODAY the photo "most definitely does not show Antarctic plants."

"The purple flower looks very much like Saxifraga oppositifolia − Purple saxifrage − which is frequent in the Arctic," the spokesperson said.

Skip Walker , director of the Alaska Geobotany Center, also told USA TODAY the plants in the photo are likely from the Arctic.

"I can't identify the plants with certainty, but they all look like Arctic plants," he said in an email.

Matt Davey , an ecologist at the Scottish Association for Marine Science, told USA TODAY there are only two species of flowering plants in Antarctica: Colobanthus quitensis and Deschampsia antarctica .

"The flowers in (the) photo are definitely not the two Antarctic flowering plants," he said in an email.

Fact check : Greenland's Petermann Glacier is shrinking; movement doesn't mean it's growing

The text associated with the image seems to loosely quote a 2022 paper co-authored by Nicoletta Cannone, an ecology professor at the University of Insubria in Italy.

While the photo in the post does not show Antarctic plants, Cannone's paper does document a global warming-related expansion in the range of both Colobanthus quitensis and Deschampsia antarctica on the continent's Signy Island.

Global warming has also caused the retreat of ice shelves on the Antarctic Peninsula, according to Discovering Antarctica , a website created by various U.K. government and research entities.

USA TODAY reached out to the Instagram user who shared the post for comment but did not immediately receive a response.

AFP also debunked the claim.

Our fact-check sources:

• Matt Davey , Oct. 5-6, Email exchange with USA TODAY
• Skip Walker , Oct. 5, Email exchange with USA TODAY
• Alamy, Feb. 23, 2017, Iceberg floating in the water off the coast of Greenland. Flowers on the shore. Nature and landscapes of Greenland
• Current Biology, Feb. 14, 2022, Acceleration of climate warming and plant dynamics in Antarctica
• Discovering Antarctica, accessed Oct. 4, Impacts of climate change
• Australian Antarctic Program, July 20, 2022, Climate change poses greatest threat to Antarctica
• Global Biodiversity Information Facility, accessed Oct. 6, Saxifraga oppositifolia L.
• Global Biodiversity Information Facility, accessed Oct. 6, Colobanthus quitensis(Kunth) Bartl.
• New Scientist, Feb. 14, 2022, Flower growth in Antarctica is accelerating due to warming climate

Thank you for supporting our journalism. You can subscribe to our print edition, ad-free app or e-newspaper here .

Our fact-check work is supported in part by a grant from Facebook.

Global warming may be factor in deadly Italian shipwreck, climatologist says

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Islamic State claims responsibility for knife attack in Germany

Police detained a teenager, while the perpetrator was still at large.