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*Free* ExxonMobil’s own global warming projections predicted climate warming, quantitative analysis shows

Summary author: Walter Beckwith

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

Since the late 1970s and early 1980s, climate models used internally by ExxonMobil’s own scientists accurately projected and skillfully modeled global warming due to fossil fuel burning and produced results that were consistent with independent academic and government climate models at the time, according to a new Review. Although it has been widely reported that Exxon has known about the threat of global warming since the 1970s, “this study is the first quantitative review of the company’s early climate science,” according to a related press release included in the press package. Internal documents disclosed in 2015 have suggested that ExxonMobil scientists have informed company executives about dangerous human-driven climate warming since at least 1977. However, while the text of these documents has been examined in detail, far less attention has been given to numerical and graphical data in these documents related to explicit projections of future warming. In this Review, Geoffrey Supran and colleagues systematically evaluated the accuracy of ExxonMobil’s internal climate modeling projections – some of the most abundant and robust in the industry – and compared their performance against academic and government models. Supran et al. analyzed 32 internal documents produced by ExxonMobil scientists between 1977 and 2002 and 72 peer-reviewed scientific publications authored or coauthored by ExxonMobil scientists between 1982 and 2014 – a dataset that constitutes all publicly available internal documents and research publications disclosed by the company. According to the findings, the climate projections reported by ExxonMobil scientists during this period were accurate in predicting subsequent global climate warming, suggesting that the company understood as much about climate change as academic and government scientists did, despite their active efforts to sow uncertainty and doubt. “These findings corroborate and add quantitative precision to assertions by scholars, journalists, lawyers, politicians, and others that ExxonMobil accurately foresaw the threat of human-caused global warming, both prior and parallel to orchestrating lobbying and propaganda campaigns to delay climate action, and refute claims by ExxonMobil Corp and its defenders that these assertions are incorrect,” write Supran et al.

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JOURNAL

Science

DOI

10.1126/science.abk0063 

ARTICLE TITLE

Assessing ExxonMobil’s global warming projections

New Harvard study puts a number on what ‘Exxon knew’ decades ago about climate science

Peer-Reviewed Publication

HARVARD UNIVERSITY

 

IMAGE: SUMMARY OF ALL GLOBAL WARMING PROJECTIONS REPORTED BY EXXONMOBIL SCIENTISTS IN INTERNAL DOCUMENTS AND PEER-REVIEWED PUBLICATIONS BETWEEN 1977 AND 2003 (GRAY LINES), SUPERIMPOSED ON HISTORICALLY OBSERVED TEMPERATURE CHANGE (RED). SOLID GRAY LINES INDICATE GLOBAL WARMING PROJECTIONS MODELED BY EXXONMOBIL SCIENTISTS THEMSELVES; DASHED GRAY LINES INDICATE PROJECTIONS INTERNALLY REPRODUCED BY EXXONMOBIL SCIENTISTS FROM THIRD-PARTY SOURCES. SHADES OF GRAY SCALE WITH MODEL START DATES, FROM EARLIEST (1977: LIGHTEST) TO LATEST (2003: DARKEST). view more 

CREDIT: GEOFFREY SUPRAN

Cambridge, MA — Climate projections reported by ExxonMobil scientists between 1977 and 2003 were accurate and skillful in predicting subsequent global warming and contradicted the company’s public claims, a new Harvard study shows.

 

In the first ever systematic assessment of the fossil fuel industry’s climate projections, researchers at Harvard University and the Potsdam Institute for Climate Impact Research have put a number on what ‘Exxon knew’ decades ago about climate science: that fossil fuel burning would lead to 0.20 ± 0.04 degrees Celsius of global warming per decade. 

 

The findings, published in the peer-reviewed journal Science and summarized by a single chart displaying every global warming projection reported by Exxon and ExxonMobil Corp scientists between 1977 and 2003, are based on statistical analyses of never-previously reported data buried in the company’s own documents. 

Although it has been widely reported that Exxon has known about the threat of global warming since the 1970s, this study is the first quantitative review of the company’s early climate science. Previous research focused on Exxon's inconsistent internal and external rhetoric on climate change. This report dives into company data revealing that the company knew how much warming would occur with startling accuracy.

 

“We find that most of their projections accurately forecast warming consistent with subsequent observations,” the report concludes. “Their projections were also consistent with, and at least as skillful as, those of independent academic and government models.”

 

Using established IPCC statistical techniques, the study finds that 63-83% of global warming projections reported by ExxonMobil scientists were consistent with subsequently observed temperatures. Moreover, projections modeled by ExxonMobil scientists had an average ‘skill score’ of 72 ± 6 %, with the highest scoring 99%. For comparison, NASA scientist Dr. James Hansen’s global warming predictions presented to the U.S. Congress in 1988 had skill scores ranging from 38% to 66%. (When we account for differences between forecast and observed atmospheric CO2 levels, the ‘skill score’ of projections modeled by ExxonMobil scientists was 75 ± 5%, with seven projections scoring 85% or above. Again, for comparison, Hansen’s 1988 projections had corresponding skill scores of 28 to 81%.)

 

 

The study finds that “Exxon and ExxonMobil Corp also correctly rejected the prospect of a coming ice age, accurately predicted when human-caused global warming would first be detected, and reasonably estimated the ‘carbon budget’ for holding warming below 2°C. On each of these points, however, the company’s public statements about climate science contradicted its own scientific data.”

 

The study adds weight to ongoing legal and political investigations into ExxonMobil.

 

“These findings corroborate and add quantitative precision,” the authors write, “to assertions by scholars, journalists, lawyers, politicians, and others that ExxonMobil accurately foresaw the threat of human-caused global warming, both prior and parallel to orchestrating lobbying and propaganda campaigns to delay climate action, and refute claims by ExxonMobil Corp and its defenders that these assertions are incorrect.”

 

“This is the nail-in-the-coffin of ExxonMobil’s claims that it has been falsely accused of climate malfeasance,” commented lead author and Harvard University Research Associate Geoffrey Supran (Supran began as an Associate Professor of Environmental Science and Policy at the University of Miami’s Rosenstiel School of Marine, Atmospheric, and Earth Science Jan 2023). “Our analysis shows that ExxonMobil’s own data contradicted its public statements, which included exaggerating uncertainties, criticizing climate models, mythologizing global cooling, and feigning ignorance about when — or if — human-caused global warming would be measurable, all while staying silent on the threat of stranded fossil fuel assets.”

 

The paper’s Acknowledgments state that this research was supported by Harvard University Faculty Development Funds and by the Rockefeller Family Fund.

 

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JOURNAL

Science

DOI

10.1126/science.abk0063 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Assessing ExxonMobil’s global warming projections

 

Global warming intensifies typhoon-induced extreme precipitation over East Asia

Peer-Reviewed Publication

POHANG UNIVERSITY OF SCIENCE & TECHNOLOGY (POSTECH)

 

IMAGE: 

SIMULATION OUTCOMES FROM CLIMATE MODELS FOR FOUR POTENT TYPHOONS (SANBA, CHABA, MAYSAK, AND HAISHEN) THAT RECENTLY HIT THE KOREAN PENINSULA UNDER TWO CONDITIONS: CURRENT CLIMATE CONDITION INCLUDING ALL ANTHROPOGENIC AND NATURAL FACTORS (ALL) AND COUNTERFACTUAL CONDITION DEVOID OF ANTHROPOGENIC WARMING EFFECTS (NAT)

[LEFT] PROBABILITY DISTRIBUTION OF TYPHOON 6-HOUR PRECIPITATION (% GRID)

- THE BAR GRAPH ILLUSTRATES THE LIKELIHOOD OF RAINFALL EXTREMES.

- THE EXTREME PRECIPITATION AREA IS EXPANDED BY 16 TO 37% DUE TO GLOBAL WARMING.

[RIGHT] SPATIAL DISTRIBUTION OF TYPHOON PRECIPITATION (500 KM RADIUS) UNDER ALL CONDITIONS AND ITS DIFFERENCE FROM NAT RESULTS (IN MM/6 HOURS)

- THE ENHANCED PRECIPITATION RESULTING FROM GLOBAL WARMING TENDS TO CONCENTRATE WITHIN THE CENTRAL REGION OF THE TYPHOON.

view more 

CREDIT: POSTECH

Last year, Typhoon Hinnamnor – which caused 36 fatalities – gained notoriety as the first super typhoon that developed at a high latitude as 25°N since Korea Meteorological Administration records began. This year in Osong, Chungcheongbuk-do, an unanticipated intense downpour, caused rivers to suddenly overflow, resulting in numerous casualties. Earth's rising temperatures are triggering unprecedented typhoons, torrential rains, and other extreme weather events. Without reliable predictions of climate extremes prompted by global warming, mitigating the resultant damages remains a challenge.

 

Professor Seung-Ki Min and Dr. Minkyu Lee, from the Division of Environmental Science and Engineering at Pohang University of Science and Technology (POSTECH), have used a high-resolution climate model to conduct a pioneering quantitative analysis of the impact of global warming on typhoons making landfall on the Korean Peninsula. This research has been recently published in npj Climate and Atmospheric Science.

 

Notably, global warming is giving way to a surge in more powerful typhoons which maintain its intensity longer and thereby cause stronger damage. Accurate typhoon prediction and damage reduction necessitate better understanding of the global warming influences, for which climate model simulations with a km-scale resolution are eccential. However, studies quantifying the anthropogenic warming contribution to typhoons affecting Korea, especially research into the rainfall extremes accompanying typhoons, remain scant.

 

To overcome this, the research team designed a 3 km high-resolution regional climate model simulation to investigate the impact of global warming on typhoon intensity and extreme precipitation. Four extremely strong typhoons that made landfall on the Korean Peninsula between 2011 and 2020 were chosen for simulation under current climate condition and counterfactual condition without human-induced warming. To reduce the uncertainties in regional sea surface temperature changes due to global warming, they utilized diverse ocean warming patterns estimated from CMIP6 multiple climate models.

 

The findings show that accounting for global warming from human activities augmented overall typhoon intensity and precipitation. The research team observed that the impact of warming was pronounced more strongly at maximum typhoon intensity than the average intensity. This implies more frequent occurrences of powerful super typhoons over East Asia in the future. Additionally, the area exposed to extreme rainfall generated by typhoons expanded 16 to 37 percent due to warmer climate conditions. Further, the expansion of extreme precipitation area is attributed to the strengthening of upward motion near the typhoon center and the increase in atmospheric water vapor due to the ocean surface warming.

 

Professor Min explained, “Our results from high-resolution climate model simulations provide conclusive evidence that global warming has amplified the strength of recent typhoons making landfall on the Korean Peninsula. Continued escalation of global warming could lead to stronger typhoons and more extensive occurrences of rainfall extremes, demanding heightened sector-specific preparedness measures.”

 

This study received support from the Mid-Career Researcher Program of the National Research Foundation of Korea and the Korea Meteorological Administration Research and Development Program on Climate and Climate Change Monitoring and Prediction Information Application Technology.

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JOURNAL

npj Climate and Atmospheric Science

DOI

10.1038/s41612-023-00509-w 

ARTICLE TITLE

Convection-permitting simulations reveal expanded rainfall extremes of tropical cyclones affecting South Korea due to anthropogenic warming

How we know humans cause global warming: A brief history of climate science  Fact check

Kate S. Petersen, USA TODAY
Updated Wed, December 20, 2023 

The claim: No one has shown that human CO2 emissions drive global warming

An Oct. 3 Facebook video (direct link, archive link) shows Ian Plimer, a skeptic of human-driven climate change, speaking at the Australian Conservative Political Action Conference in 2022.

"Game over. We are dealing with a fraud," the video is captioned. "Geologist, Professor Ian Plimer, exposes the monumental fraud that is 'human-induced global warming' in just two minutes: 'No one has ever shown that human emissions of carbon dioxide drive global warming … And if it could be shown, then you would have to show that the 97% of emissions which are natural, do not drive global warming.'"

The post was shared more than 3,000 times in two months.

More from the USA TODAY Fact-Check Team:

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Our rating: False

More than a century of experimental and observational research by generations of scientists shows that modern global warming is driven by greenhouse gases emitted by human activity. Scientists know that natural CO2 emissions are not driving modern global warming because they are reabsorbed by natural "carbon sinks." However, additional emissions by humans have resulted in excess greenhouse gas accumulation in the atmosphere − driving global warming.

Multiple lines of evidence and decades of research show humans are causing climate change

Human CO2 emissions have warmed the planet by amplifying Earth's "greenhouse effect" − the process by which greenhouse gases slow the release of heat into space. Scientists determined this through a lengthy process, which included establishing that CO2 is a greenhouse gas, determining that both CO2 and temperatures are increasing, determining that the increase in atmospheric CO2 is due to human behavior 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 CO2, warm the planet by absorbing radiation otherwise destined for space.

After absorbing this radiation, CO2 molecules release their own radiation − some of which makes its way into space. But some of it also gets directed laterally to be absorbed by other CO2 molecules or back down to the Earth, effectively trapping warmth in the lower atmosphere.

Scientists have repeatedly confirmed the existence of this physical process.

"The theory and mathematics of radiation passing through gases are clearly defined," Michael Roman, a planetary scientist at the University of Leicester, previously told USA TODAY. The greenhouse effect has "been verified by laboratory experiments and meteorological observations."

Can we count on renewable energy? Four ways wind, solar and water can power the US

Researchers have also shown that Earth's atmospheric CO2 concentrations are rising. For instance, in 1938, British engineer Guy Callendar determined that concentrations were increasing by analyzing historical records.

Two decades later, in 1958, geochemist Charles Keeling began daily measurements of atmospheric CO2 concentrations at the Mauna Loa station in Hawaii. Ongoing station measurements show that CO2 concentrations have increased by more than 100 ppm since then, rising to 420 ppm.

Callendar also reported that Earth's temperature had warmed, a finding that has been subsequently verified by multiple independent climate agencies based on global temperature sensors and satellite data. Modern scientists have also documented the consequences of this warming, which include glacial and polar ice melt, sea level rise − due to both ice melt and the expansion of warming seawater − and an increase in the frequency of certain extreme weather events, such as heat waves.

Based on the physics of the greenhouse effect and other processes, a certain amount of warming should result from a given increase in atmospheric greenhouse gas concentrations on Earth. And this is what scientists have observed.

"The amount of warming we see matches what we expect based on the increased CO2 we've added," Josh Willis, a NASA climate scientist, previously told USA TODAY. "The timing of the warming matches the timing of the CO2 increase caused by people. Not only that, the timing of global sea level rise matches the CO2 increase."

Successful predictions show climate science is sound

Scientists have successfully leveraged their understanding of greenhouse gas and climate physics to predict future warming far in advance.

For instance, in the 1970s, scientists at oil giant ExxonMobil predicted decades of CO2-driven global warming before it occurred.

Harvard University historian of science Naomi Oreskes co-authored a 2023 analysis of ExxonMobil data from that time, reporting in the paper that "63 to 83% of the climate projections reported by ExxonMobil scientists were accurate in predicting subsequent global warming."

In an email to USA TODAY, she called the Facebook post's claim "preposterous."

Past independent academic and government projections have also been relatively accurate, according to a 2017 Carbon Brief analysis of eight "prominent" climate models published between 1973 and 2013.

"Climate models published since 1973 have generally been quite skillful in projecting future warming," wrote Zeke Hausfather, the author of the analysis, who was working as a research scientist at Berkeley Earth at the time. "While some were too low and some too high, they all show outcomes reasonably close to what has actually occurred, especially when discrepancies between predicted and actual CO2 concentrations and other climate forcings are taken into account."

Past scientists also used their understanding of greenhouse gas and climate physics to predict that, while Earth's lower atmosphere would warm as CO2 levels increase, the stratosphere − an atmospheric layer roughly between 6 and 30 miles above the Earth's surface − would cool.

This stratospheric cooling, caused in part by the increased retention of radiation in the lower atmosphere, has since been documented by researchers using weather balloon and satellite measurements.

In addition to demonstrating that CO2 has increased and warmed the lower atmosphere, scientists have also confirmed that the excess CO2 in the atmosphere is due to human emissions.

One clue is that "the accumulation in the atmosphere matches the amount we've added through burning fossil fuels," Hausfather previously told USA TODAY.

Additionally, modern atmospheric CO2 contains a disproportionately high amount of a certain type of carbon − the type found in fossil fuels.

"There are many different 'fingerprints' that have been clearly identified by scientists as evidence that industrial pollution is the cause of recent global heating," Dargan Frierson, an atmospheric scientist at the University of Washington, told USA TODAY in an email. "This is not exactly a 'whodunit' situation. The evidence is overwhelming that fossil fuel burning is the culprit."

Natural CO2 emissions reabsorbed in 'carbon sinks,' humans tipped the scale

The post also implies that if natural CO2 emissions dwarf human emissions, then human CO2 cannot be the driver of climate change. That is wrong.

Currently, around 95% of annual CO2 emissions are natural, according to the 2022 Global Carbon Budget. This is similar to the figure in the post.

However, Earth's ecological systems reabsorb natural emissions in “carbon sinks,” such as forests, as part of Earth's carbon cycle, Gavin Schmidt, a NASA climate scientist, told USA TODAY.

Excess CO2 emissions are accumulating in the atmosphere because Earth's natural carbon sinks do not have the capacity to absorb all of the extra CO2 that humans emit, he said.

After decades of accumulation, atmospheric CO2 levels have increased by 50% since pre-industrial times, rising to levels unprecedented in hundreds of thousands of years, according to the National Oceanic and Atmospheric Administration.

Fact check: Humans are responsible for a significant amount of CO2 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 debunked the claim.

Our fact-check sources:

• Mark Zelinka, Dec. 4, Email exchange with USA TODAY

• Dargan Frierson, Dec. 13, Email exchange with USA TODAY

• Naomi Oreskes, Dec. 15, Email exchange with USA TODAY

• Gavin Schmidt, June 7, Email exchange with USA TODAY

• USA TODAY, Jan. 20, Fact check: Global warming caused by greenhouse gas emissions, not mysterious ocean warming

• USA TODAY, Dec. 5, 2021, Fact check: Human-generated CO2, not water vapor, drives climate change

• USA TODAY, Nov. 1, False claim 'climate crisis hoax' statement signed by thousands of scientists | Fact check

• USA TODAY, June 26, Humans are responsible for a significant amount of CO2 in the atmosphere | Fact check

• USA TODAY, Jan. 10, Fact check: Global temperatures and atmospheric CO2 levels are correlated, contrary to claim

• USA TODAY, Nov. 29, Global warming is from human activity, not sea volcanos or El Niño | Fact check

• USA TODAY, Feb. 27, Fact check: Carbon dioxide has an effect on the climate, contrary to post

• USA TODAY, Nov. 28, Fact check: Earth's warming well documented, other planets' climate data limited

• Australian Department of Climate Change, Energy and the Environment and Water, accessed Nov. 26, Understanding climate change

• The Conversation, July 21, 2020, John Tyndall: the forgotten co-founder of climate science

• NASA Vital Signs of the Planet, March 25, 2021, Direct Observations Confirm That Humans Are Throwing Earth's Energy Budget off Balance

• NASA Vital Signs of the Planet, accessed Dec. 15, Causes

• NASA Vital Signs of the Planet, accessed Dec. 15, Global temperature

• NASA Vital Signs of the Planet, accessed Dec. 15, Carbon dioxide

• NASA Vital Signs of the Planet, accessed Dec. 15, Ocean warming

• NASA Vital Signs of the Planet, accessed Dec. 15, Ice sheets

• NASA Vital Signs of the Planet, accessed Dec. 15, Sea level

• NASA Earth Observatory, accessed Dec. 15, World of Change: Global Temperatures

• Environmental Protection Agency, July 2022, Climate Change Indicators: Heat Waves

• Environmental Protection Agency, accessed Nov. 26, Climate Change Indicators: Weather and Climate

• NOAA, Oct. 12, 2022, How do we know the build-up of carbon dioxide in the atmosphere is caused by humans?

• NOAA, May 12, Climate Change: Atmospheric Carbon Dioxide

• University Corporation for Atmospheric Research, accessed Dec. 12, History of Climate Change Interactive Timeline

• University Corporation for Atmospheric Research, accessed Dec. 15, The Stratosphere

• Carbon Brief, April 28, 2021, Melting glaciers drove ‘21% of sea level rise’ over past two decades

• Carbon Brief, Oct. 5, 2017, Analysis: How well have climate models projected global warming?

• BBC, April 26, 2013, Guy Stewart Callendar: Global warming discovery marked

• Wired, Jan. 23, 2018, Meet the Amateur Scientist Who Discovered Climate Change

• The Harvard Gazette, Jan. 12, Exxon disputed climate findings for years. Its scientists knew better

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• Global Carbon Project, 2022, Global Carbon Budget 2022

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• University of California Los Angeles, Aug. 21, Stratospheric cooling: The concerning flip side of global warming

• World Resources Institute, Jan. 21, 2021, Forests Absorb Twice As Much Carbon As They Emit Each Year

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This article originally appeared on USA TODAY: Is global warming caused by humans? Evidence says yes | Fact check