A new study puts a number on what Exxon has known for decades about climate science

A new Harvard study puts a number on what Exxon has known for decades about climate science

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 designed by ExxonMobil scientists themselves; Gray dashed lines indicate projections produced internally by ExxonMobil scientists from external sources. Grayscale with pattern start dates, from oldest (1977: lightest) to newest (2003: darkest). Credit: Jeffrey Soprane

A new Harvard study showed that climate projections reported by ExxonMobil scientists between 1977 and 2003 were accurate and adept at predicting subsequent global warming and contradicted the company’s public claims.

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 put a number on what Exxon has known for decades about climate science: that burning fossil fuels will result in 0.20 ± 0.04°C of global warming per decade.

Results published in the peer-reviewed journal Sciences Summarized by a single chart showing all projections of global warming reported by Exxon and ExxonMobil Corp scientists between 1977 and 2003, it is based on statistical analyzes of previously unreported 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 has focused on Exxon’s inconsistent internal and external rhetoric on climate change. This report delves into company data revealing that the company knew how much warming was going to happen with amazing accuracy.

“Most of their predictions accurately predict warming consistent with subsequent observations,” the report concludes. “Their predictions were also consistent with, and at least as subtle as, those of the academic and independent government models.”

Using IPCC-approved statistical techniques, the study found that 63-83% of global warming projections reported by ExxonMobil scientists were consistent with later observed temperatures. Furthermore, the predictions formulated by ExxonMobil scientists had an average “skill score” of 72 ± 6%, with the highest score being 99%. For comparison, NASA scientist Dr. James Hansen’s global warming predictions presented to the US Congress in 1988 ranged from 38% to 66%. (When we factor in the differences between the forecast and the observed atmospheric carbon dioxide2 At levels, the “skill score” for forecasts designed by ExxonMobil scientists was 75 ± 5%, with seven forecasts scoring 85% or higher. Again, for comparison, Hansen’s 1988 predictions had corresponding skill scores ranging from 28 to 81%.)

The study found that “Exxon and ExxonMobil Corp. also correctly rejected the possibility of a coming ice age, accurately predicted when human-caused global warming would first be detected, and reasonably estimated a ‘carbon budget’ for a decade of warming below 2°C. Each of these points, However, the company’s public statements about climate science contradict its private scientific data.”

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

The authors write: “These findings confirm and add quantitative accuracy to assertions by scientists, journalists, lawyers, politicians, and others that ExxonMobil accurately predicted the threat of human-caused global warming, both prior to and in parallel with lobbying and publicity campaigns to delay climate action, refuting ExxonMobil Corp.’s claims and its defenders that these assertions are untrue.”

Commented lead author and research assistant at Harvard University Jeffrey Soprane (Soprane began as an associate professor of environmental science and policy at the university” from the Rosenstiel School of Marine, Atmospheric, and Earth Sciences in Miami, January 2023). Uncertainty, criticism of climate models, mythologization of global cooling, feigning ignorance about when — or if — human-caused global warming will be measurable, all while remaining silent about the threat to stranded fossil fuel assets.”

The paper notes that this research was supported by the Harvard Faculty Development Funds and the Rockefeller Family Fund.

more information:
Subran, Evaluating Global Warming Projections for ExxonMobil, Sciences (2023). DOI: 10.1126/science.abk0063. www.science.org/doi/10.1126/science.abk0063

Provided by Harvard University

the quote: New study puts a number on what Exxon has known for decades about climate science (2023, January 12) Retrieved January 12, 2023 from https://phys.org/news/2023-01-exxon-knew-decades-climate- science. html

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