President Biden has repeatedly and rightly called climate change an “existential threat.” The White House, the Pentagon and the intelligence community have all issued reports detailing climate change’s “threat multiplier,” which will worsen food and water scarcity, spread diseases, destabilize countries, and exacerbate mass migration. Most Americans increasingly understand that the threat is critical—and getting worse.

Yet, despite some progress, the United Nations climate summit in Glasgow, Scotland—which US Special Climate Envoy John F. Kerry dubbed the world’s “last best hope” to avoid disaster—will end this week in disappointment. With China and Russia absent and refusing to accelerate their plans on greenhouse gas emission reductions, the goal of preventing temperature rises beyond 1.5 degrees Celsius becomes ever more fanciful. That condemns the world to deadlier heat waves, more destructive floods, more frequent wildfires, and more cataclysmic weather.

To his credit, Biden has insisted that climate be one of the security priorities of his administration, and his Build Back Better plan—even in its reduced state—contains the government’s largest climate investment ever. And yet, the administration has not begun the necessary rethinking—and reprioritizing—needed to address our most pressing national security challenge.

Read the full text of Katrina’s column here.