Secretary of Defense James Mattis told the Senate Armed Services Committee that climate change poses a national security threat in a previously unpublished written testimony following his confirmation hearing in January, reports ProPublica.

The media outlet says “someone involved with coordinating efforts on climate change preparedness across more than a dozen government agencies” provided the 58-page document, which senators on the committee can choose to publish—or not.

In a story published yesterday (March 14), ProPublica laid out excerpts of how Mattis responded to questions on climate change, a vast difference from how many others in the current administration view it. Mattis said, per ProPublica:

“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.”

Mattis went on in a separate question to say that “the Department of Defense must pay attention to potential adverse impacts generated by this phenomenon.” He also confirmed that, as secretary, he’d ensure the department play “its appropriate role” in addressing the impacts of climate change.

As ProPublica stated, this is the “first direct signal of [Mattis’] determination to recognize climate change.” In the past, the secretary has expressed hints of environmental awareness: in his support to reduce fossil fuel dependence and by signing the 2010 Joint Operating Environment, a study that lists climate change and natural disasters as worldwide security threat.

This way of thinking was encouraged under former President Barack Obama, who issued a presidential memorandum in September 2016 to ensure that climate impacts become fully embedded into national security plans.

(H/t ProPublica)