During his confirmation hearing in January, Secretary of Defense James Mattis vowed that the Department of Defense would take the national security challenges posed by climate change seriously, despite the President Donald Trump’s well-documented skepticism on the matter. But a new government report suggests the Pentagon isn’t taking all the necessary steps to address climate’s impact on readiness worldwide — and the delay may be rooted in a delicate dance by DoD officials to reconcile its security concerns with the White House’s firm opposition to mainstream climate research.