Should temperatures climb four degrees Celsius as many scientists fear, we could be facing drought, mass extinctions and worse.
Underfunding, lack of strategic planning and denialism are hindering the department's climate response.
A new report indicates the government is unwilling to take action, because its officials believe the planet's fate is already sealed.
"We face a direct existential threat," warns Secretary General António Guterres, "[because] climate change is moving faster than we are."
"Either we act with unprecedented speed, or we face a bleak future," argue authors David Splatt and Ian Dunlop.
It is unknown whether Trump will announce the end of the 2015 deal or push for a renegotiation.
Meeting in the Oval Office on Tuesday with French President Emmanuel Macron, the president says Iran faces "bigger problems" if it restarts its nuclear program.
The president echoes the message of his 2016 campaign and declares, "America is in the game, and America is going to win."