"I was so lucky to get out," a hiker tells the BBC after being caught in two days of unusually heavy snow in the Himalayas.

"I was so lucky to get out," a hiker tells the BBC after being caught in two days of unusually heavy snow in the Himalayas.

Earth's climate has fluctuated between cold and warm periods for millions of years. During the so-called "lukewarm interglacials"—warm phases between 800,000 and 430,000 years ago—atmospheric CO2 ...

Heat has always been something we thought we understood. From baking bread to running engines, the idea seemed simple: heat spreads out smoothly, like water soaking through a sponge. That simple ...