Delger Erdenesanaa

Scientists used tree rings to compare last year’s extreme heat with temperatures over the past two millenniums.

The number of tornadoes so far in the United States this year is just above average. But their distribution is changing.

Around the world, grass-roots organizers and Indigenous communities are taking proposed coal, oil and gas projects to court — and winning.

Paris is becoming a city of bikes. Across China, people are snapping up $5,000 electric cars. On Earth Day, a look at a few bright spots for emission reductions.

Development and groundwater pumping are causing land subsidence and heightening the risks of sea level rise.

A global survey found harmful levels even in water samples taken far from any obvious source of contamination.

There have been record temperatures every day for more than a year. Scientists are investigating what’s behind the extraordinary measurements.

Climate change is making heat waves linger for longer stretches of time, exacerbating the effects of extreme temperatures.

Temperatures in the region rose above 40 degrees Celsius in February, with humidity pushing the heat index even higher.

New research found that fewer than 10 percent of countries and territories met World Health Organization guidelines for particulate matter pollution last year.