Fifty-five years after the first Earth Day, climate activists organized a nationwide celebration of solar power.

© Kaleb Autman for The New York Times

Pollution from fires, intensified by rising temperatures, is on track to become one of America’s deadliest climate disasters.

© The New York Times

Most corals in the Atlantic Ocean will soon stop growing. Many are already dying, leaving shorelines and marine ecosystems vulnerable.

© Jason Gulley for The New York Times

The Trump administration wants to switch off and possibly destroy the climate-monitoring technology.

© NASA