Claim: No one has proven that human carbon dioxide emissions cause global warming
Facebook video from 3 October (direct link, archive link) shows human-driven climate change skeptic Ian Plimer speaking at the 2022 Australian Conservative Political Action Conference.
The video is titled: “Game Over. We’re Dealing with Fraud.” “Geologist Professor Ian Plimmer exposes the huge ‘human-caused global warming’ hoax in just two minutes: ‘ No one has proven that human emissions of carbon dioxide cause global warming, and if you could prove that, you would have to show that 97% of natural emissions do not cause global warming.”
The post was retweeted more than 3,000 times in two months.
More from USA TODAY’s fact-checking team:
Our rating: False
More than a century of experimental and observational research by generations of scientists has shown that modern global warming is driven by greenhouse gases emitted by human activities. Scientists know that natural carbon dioxide emissions do not contribute to modern global warming because they are reabsorbed by natural “carbon sinks.” However, additional human emissions lead to excessive accumulation of greenhouse gases in the atmosphere, which in turn contributes to global warming.
Multiple lines of evidence and decades of research show humans are causing climate change
Human emissions of carbon dioxide amplify the Earth’s “greenhouse effect,” in which greenhouse gases slow the release of heat into space, thereby warming the planet. Scientists determined this through a long process that included determining that carbon dioxide is a greenhouse gas, determining that both carbon dioxide and temperature are increasing, determining that the increase in atmospheric carbon dioxide is due to human actions, and using this knowledge to accurately predict Future warming.
In the mid-1800s, scientists Eunice Foote and John Tyndall experimentally demonstrated that CO2 is a greenhouse gas. These gases, such as carbon dioxide, warm the Earth by absorbing radiation that would otherwise enter space.
After absorbing radiation, the carbon dioxide molecules release their own radiation, some of which travels into space. But some of it is also directed sideways, absorbed by other carbon dioxide molecules or returned to Earth, effectively trapping heat in the lower atmosphere.
Scientists have confirmed the existence of this physical process many times.
“The theory and mathematics of radiation traveling through gases is well defined,” Michael Roman, a planetary scientist at the University of Leicester, previously told USA Today. The greenhouse effect “has been verified through laboratory experiments and meteorological observations.”
Can we rely on renewable energy?Four ways wind, solar and hydro power the U.S.
Researchers also show that the concentration of carbon dioxide in Earth’s atmosphere is rising. For example, in 1938, British engineer Guy Callendar determined that concentrations were increasing by analyzing historical records.
Twenty years later, in 1958, geochemist Charles Keeling began taking daily measurements of atmospheric carbon dioxide concentrations at the Mauna Loa station in Hawaii. Ongoing monitoring station measurements show that carbon dioxide levels have increased by more than 100 ppm since then, to 420 ppm.
Kalendar also reported that Earth’s temperatures have warmed, a finding that was later confirmed by multiple independent climate agencies based on global temperature sensor and satellite data. Modern scientists have also documented the consequences of this warming, which include melting of glaciers and polar ice, rising sea levels due to melting ice and warming ocean waters, and an increase in the frequency of certain extreme weather events, such as heat waves.
According to the physics of the greenhouse effect and other processes, a certain increase in the concentration of greenhouse gases in the Earth’s atmosphere should lead to a certain amount of warming. This is what scientists observed.
“The amount of warming we’re seeing is consistent with what we would expect based on increased carbon dioxide,” NASA climate scientist Josh Willis previously told USA Today. “The timing of the warming is consistent with human-caused carbon dioxide.” The timing of the increase matches that of the increase. Not only that, but the timing of global sea level rise also matches the timing of the increase in carbon dioxide.”
Successful predictions show climate science is sound
Scientists are successfully using their understanding of greenhouse gases and climate physics to predict future warming in advance.
For example, in the 1970s, scientists at oil giant ExxonMobil predicted that global warming caused by carbon dioxide would continue for decades.
Naomi Oreskes, a historian of science at Harvard University who co-authored a 2023 analysis of ExxonMobil data at the time, reported in the paper that “between 63% and 83% of the climate predictions reported by ExxonMobil scientists were The subsequent global warming aspect is accurate.”
In an email to USA TODAY, she called the Facebook post’s claims “ridiculous.”
Independent academic and government forecasts have also been relatively accurate in the past, according to a 2017 Carbon Brief analysis of eight “well-known” climate models released between 1973 and 2013.
“Climate models released since 1973 are generally quite adept at predicting future warming,” wrote Zeke Hausfather, author of the analysis and then a research scientist at Berkeley Earth. “While some are too low and some are too high, They all show results that are reasonably close to what actually occurs, especially when differences between predicted and actual carbon dioxide concentrations and other climate forcings are taken into account.”
Past scientists have also used their understanding of greenhouse gas and climate physics to predict that while Earth’s lower atmosphere will warm as carbon dioxide levels increase, the stratosphere (the layer of atmosphere about 6 to 30 miles above the Earth’s surface) will It will get cold.
This cooling of the stratosphere is caused in part by increased retention of radiation in the lower atmosphere, which researchers have documented using weather balloons and satellite measurements.
In addition to demonstrating that carbon dioxide is increasing and warming the lower atmosphere, scientists have also confirmed that excess carbon dioxide in the atmosphere is due to human emissions.
Hausfather previously told USA TODAY that one clue is that “the amount accumulated in the atmosphere matches the amount we add by burning fossil fuels.”
Additionally, carbon dioxide in the modern atmosphere contains disproportionately large amounts of certain types of carbon, the type found in fossil fuels.
Dargan Frierson, an atmospheric scientist at the University of Washington, told USA TODAY in an email: “Scientists have clearly identified a number of different ‘fingerprints’ as industrial pollution is responsible for recent global warming. of evidence.” “It’s not exactly a case of ‘whodunit’. There’s a lot of evidence that fossil fuel combustion is the culprit.”
Natural carbon dioxide emissions are reabsorbed by “carbon sinks” and humans change the scale
The article also suggests that human CO2 cannot be the driver of climate change if natural CO2 emissions dwarf human emissions. That’s wrong.
Currently, about 95% of annual carbon dioxide emissions are natural emissions, according to the 2022 Global Carbon Budget. This is similar to the picture in the post.
However, NASA climate scientist Gavin Schmidt told USA TODAY that as part of the Earth’s carbon cycle, Earth’s ecosystems reabsorb natural emissions from carbon sinks such as forests.
Excess carbon dioxide emissions are building up in the atmosphere because the Earth’s natural carbon sinks don’t have the capacity to absorb all the extra carbon dioxide humans emit, he said.
The National Oceanic and Atmospheric Administration said that over decades, atmospheric carbon dioxide concentrations have increased by 50% since pre-industrial times, rising to levels unprecedented in hundreds of thousands of years.
fact check: Humans are responsible for large amounts of carbon dioxide in the atmosphere
USA TODAY reached out to Plimer and the Facebook user who shared the post for comment but did not immediately receive a response.
Climate Feedback also refutes this claim.
Our fact-checking sources:
- Mark Zelinka, email exchange with USA TODAY, Dec. 4
- Dargan Frierson, email exchange with USA TODAY, Dec. 13
- Naomi Oreskes, email exchange with USA TODAY, Dec. 15
- Gavin Schmidt, June 7, email exchange with USA TODAY
- USA Today, January 20, Fact check: Greenhouse gas emissions cause global warming, not mysterious ocean warming
- USA Today, December 5, 2021, Fact Check: Human-generated carbon dioxide, not water vapor, causes climate change
- USA Today, November 1, False Statement Signed by Thousands of Scientists “Climate Crisis Hoax” | Fact Check
- USA Today, June 26 Humans are responsible for large amounts of carbon dioxide in the atmosphere | Fact Check
- USA Today, January 10, Fact check: Global temperatures and atmospheric carbon dioxide levels are related, contrary to claims
- USA Today, November 29 Global warming is caused by human activity, not ocean volcanoes or El Niño | Fact Check
- USA Today, February 27, Fact check: Carbon dioxide impacts climate, contrary to post
- USA Today, November 28, Fact check: Earth’s warming is well documented, but climate data on other planets is limited
- Australian Department of Climate Change, Energy, Environment and Water, visited on November 26, to learn about climate change
- The Conversation, July 21, 2020, John Tyndall: The Forgotten Co-Founder of Climate Science
- NASA Earth Vital Signs, March 25, 2021 Direct Observation Confirms Humans Are Throwing Earth’s Energy Budget Out of Balance
- NASA Earth Vital Signs, accessed December 15, why
- NASA Earth Vital Signs, accessed December 15, global temperature
- NASA Earth Vital Signs, obtained on December 15, carbon dioxide
- NASA Earth Vital Signs, accessed December 15, ocean warming
- NASA’s Earth Vital Signs, accessed December 15, Ice Sheet
- NASA Earth vital signs, obtained on December 15, sea level
- NASA Earth Observatory, accessed December 15, A Changing World: Global Temperature
- Environmental Protection Agency, July 2022, Climate Change Indicators: Heat Waves
- Environmental Protection Agency, accessed 26 November, Climate change indicators: weather and climate
- NOAA, October 12, 2022 How do we know that the accumulation of carbon dioxide in the atmosphere is caused by humans?
- NOAA, May 12, Climate Change: Atmospheric Carbon Dioxide
- University Atmospheric Research Corporation, accessed December 12, interactive timeline of climate change history
- University Atmospheric Research Corporation, accessed December 15, Stratosphere
- Carbon Brief, April 28, 2021 Melting glaciers have caused sea levels to rise 21% over the past two decades
- Carbon Brief, October 5, 2017, Analysis: How well do climate models predict global warming?
- BBC, April 26, 2013, Guy Stewart Callendar: The discovery of global warming marks the
- Wired, January 23, 2018, Meet the amateur scientists who discovered climate change
- Harvard Gazette, January 12 ExxonMobil has disputed climate findings for years.its scientists know better
- Science, January 13, assesses ExxonMobil’s global warming forecasts
- National Geographic, accessed December 17, Carbon sources and sinks
- 2022 Global Carbon Project, 2022 Global Carbon Budget
- PNAS, May 8, The special contribution of the stratosphere to human atmospheric temperature fingerprints
- UCLA, August 21, Stratosphere Cooling: The Worrying Side of Global Warming
- World Resources Institute, January 21, 2021 Forests absorb twice as much carbon as they emit every year
Thank you for supporting our journalism. You can subscribe to our print edition, ad-free app or e-newspaper here.
USA TODAY is a verified signatory of the International Fact-Checking Network, which requires an unequivocal commitment to nonpartisanship, fairness and transparency. Our fact-checking work is supported in part by Meta.
#global #warming #caused #humansEvidence #shows
Image Source : www.usatoday.com