Chat with us in Facebook Messenger. Find out what's happening in the world as it unfolds.

US President Barack Obama delivers remarks at a Clean Power Plan event at the White House in Washington, DC, August 3, 2015. President Barack Obama described climate change as one of the key challenges of our time Monday as he announced the first ever limits on US power plant emissions. As a step to try to adapt, Obama announced power plant owners must cut carbon dioxide emissions by 32 percent from 2005 levels by 2030. AFP PHOTO/JIM WATSONJIM WATSON/AFP/Getty Images
US President Barack Obama delivers remarks at a Clean Power Plan event at the White House in Washington, DC, August 3, 2015. President Barack Obama described climate change as one of the key challenges of our time Monday as he announced the first ever limits on US power plant emissions. As a step to try to adapt, Obama announced power plant owners must cut carbon dioxide emissions by 32 percent from 2005 levels by 2030. AFP PHOTO/JIM WATSONJIM WATSON/AFP/Getty Images

    JUST WATCHED

    EPA chief: Biggest step this country has ever taken

MUST WATCH

EPA chief: Biggest step this country has ever taken

CNN's Hala Gorani speaks to EPA Administrator Gina McCarthy about President Obama's newly announced plan to fight climate change.

EPA chief: Biggest step this country has ever taken

CNN's Hala Gorani speaks to EPA Administrator Gina McCarthy about President Obama's newly announced plan to fight climate change.