TPM summarizes:

Barack Obama is set to deliver a surprise speech via video to the bi-partisan Governors Global Climate Summit in Los Angeles this morning.
Obama’s team sends out the speech video, which renews Obama’s commitment to battling global warming and casts it as an economic and national security issue:
In the speech, which will also be heard by figures from some two dozen foreign countries, Obama repeatedly casts climate change as an issue requiring international cooperation.
“The United States cannot meet this challenge alone,” Obama says. Solving this problem will require all of us working together…I look forward to working with all nations to meet this challenge in the coming years.”
Obama also sends a message to leaders preparing to gather at the upcoming UN summit on climate change: “Let me also say a special word to the delegates from around the world who will gather at Poland next month: your work is vital to the planet.”