Climate Change & National Security

At more than 400 ppm, atmospheric CO2 has achieved its highest peak in 800,000 years. This increased level of atmospheric carbon dioxide has caused a rise in global surface temperatures of about one degree Celsius since 1880. Since 2001, Earth has experienced 15 of the 16 warmest years on record, and 2014, 2015, and 2016 have each been the warmest year ever recorded.


For U.S. Defense Secretary James Mattis, these facts are not just environmental matters; they impact national security and constitute a serious problem for the U.S. government. This overt position seems to indicate that Mattis will not be strictly toeing the Trump administration line, which is in contrast to Environmental Protection Agency head Scott Pruitt, who recently denied that carbon dioxide is causing global warming.

In his written responses to his January confirmation hearing questions, which were obtained and verified genuine by ProPublica, Mattis warned that climate change is already a destabilizing force:

“Climate change is impacting stability in areas of the world where our troops are operating today. It is appropriate for the Combatant Commands to incorporate drivers of instability that impact the security environment in their areas into their planning.”

“Whole-of-government Response”

Asked how the military should prepare to address the threat posed to the United States by climate change, General Mattis responded, “[c]limate change is a challenge that requires a broader, whole-of government response."

This is not a new stance for Mattis, who has repeatedly taken the position that the armed forces should explore renewable energy and cut dependence on fossil fuels. As commander of the U.S. Joint Forces Command in 2010, Mattis signed off on the Joint Operating Environment, which includes climate change among expected security threats to be confronted over the next 25 years.

His view isn't even a new one for the U.S. government: top officials have discussed the national security implications of global warming for decades, under both Republican and Democratic presidents. A “whole-of-government response” was initiated in 2016 by President Obama, who ordered more than a dozen federal offices and agencies — including the Defense Department — “to ensure that climate change-related impacts are fully considered in the development of national security doctrine, policies, and plans." These agencies were also told in December to form a Climate and National Security Working Group within 60 days — as yet, no action has been taken on that front.

It remains to be seen how Mattis will achieve his defense goals if the administration succeeds in defunding the NOAA and other bodies that conduct oceanic and atmospheric research. Mattis said it was the U.S. military's job to consider how changes like drought in regions of conflict and open-water routes in the thawing Arctic can pose challenges for defense planners and troops. He also indicated that climate change is not a distant possibility, but a real-time issue.

“I agree that the effects of a changing climate—such as increased maritime access to the Arctic, rising sea levels, desertification, among others—impact our security situation," Mattis said, "I will ensure that the department continues to be prepared to conduct operations today and in the future, and that we are prepared to address the effects of a changing climate on our threat assessments, resources, and readiness.”

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