Is it saying something when your biggest voice of reason is a guy with the nickname “Mad Dog”? Maybe.

That’s the case at the moment, as Trump’s Secretary of Defense, James “Mad Dog” Mattis, may just be one of the few people in the current administration that understands climate change.

Mattis was confirmed by the Senate in January, but ProPublica managed to get hold of some unpublished written testimony provided to the Senate Armed Services Committee after his confirmation hearing. It makes for quite interesting – and somewhat hopeful – reading.

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

One question posed to him by Democratic Senator Jeanne Shaheen asked if he thought climate change was a security threat. He replied: “Climate change can be a driver of instability and the Department of Defence must pay attention to potential adverse impacts generated by this phenomenon,” adding that climate change required a “broader, whole-of-government response.”

And he also said: “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. 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.”

The comments from Mattis probably won’t be music to Trump’s ears, who has been busy installing a bunch of climate change deniers into the White House. These include the guy who brought a snowball onto the Senate floor to disprove climate change, James Inhofe, and the new head of the Environmental Protection Agency (EPA), Scott Pruitt, who said he thought carbon dioxide wasn’t the primary cause of global warming – which is pretty much like not believing in gravity.

It might seem odd, but the military has often been a voice of reason when it comes to climate change. After all, some of its effects – such as increasing stresses on water, food, and energy – increase the possibility of national and global issues. In September 2016, various military officials said climate change presents “significant and direct risks” to the United States.

Maybe Trump will listen to Mattis. Or maybe he’ll soon be the former Secretary of Defense. Guess we’ll find out soon enough.