Trump cited MIT climate data. Not so fast, researchers say

President Trump spoke about the US role in the Paris climate change accord Thursday.
Pablo Martinez Monsivais/Associated Press
President Trump spoke about the US role in the Paris climate change accord Thursday.

In the process of making his announcement that the United States would withdraw from the Paris climate accords, President Donald Trump appeared to cite scientific findings by MIT about the impact the pact would have. Not so fast, the researchers said.

Trump said in his Rose Garden speech that even if the climate agreement were fully implemented, “it is estimated it would only produce a two-tenths of one degree -- think of that; this much -- Celsius reduction in global temperature by the year 2100. Tiny, tiny amount.”

Talking points issued by the White House said, “According to researchers at MIT, if all member nations met their obligations, the impact on the climate would be negligible. The impacts have been estimated to be likely to reduce global temperature rise by less than .2 degrees Celsius in 2100.’’


But MIT said the statement was misleading.

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“The relevant MIT researchers believe that the Paris agreement is an unprecedented and vital effort by nearly 200 countries to respond to the urgent threat of global climate change,” MIT said in a statement Thursday evening.

John Sterman, an MIT researcher who works to analyze climate change scenarios, and Andrew Jones, a researcher with the think tank Climate Interactive, told the Washington Post that their analysis shows that the current country level pledges under the Paris agreement would reduce the planet’s warming by the year 2100 down from 4.2 degrees Celsius (7.56 degrees Fahreheit) to 3.3 degrees Celsius (5.94 degrees Fahrenheit), or nearly a full degree.

The co-founder of the MIT program on climate change told The Associated Press that the administration was citing an outdated report, taken out of context. Jake Jacoby said the actual global impact of meeting targets under the Paris accord would be to curb rising temperatures by 1 degree Celsius (or 1.8 degrees Fahrenheit).

‘‘They found a number that made the point they want to make,’’ Jacoby said. ‘‘It’s kind of a debate trick.’’


MIT Technology Review reported that the “two-tenths of one degree” number cited by Trump appears to have come from a 2014 study by the MIT Joint Program on the Science and Policy of Global Change, not a 2016 study cited by the White House.

That 2014 study didn’t include all the eventual commitments to cut emissions by nations or assume that the pledges would continue beyond 2030.

“This idea that the Paris agreement has a negligible impact on future climate change is certainly not what we conveyed and was not the conclusion of our analysis. We make clear that if we want to limit warming to 2 °C, we need to do more and we need continued effort past 2030,” said Erwan Monier, co-author of the study and principal research scientist at the university’s department of Earth, Atmospheric, and Planetary Sciences.

Martin Finucane of the Globe staff contributed to this report.