NASA and NOAA: 2017 was record-setting for warmth

NASA says 2nd-warmest year on record. NOAA says 3rd-warmest. Their methodologies differ slightly, but - by both standards - the 2017 results make the past 4 years the hottest yet recorded.

Why did passenger pigeons die out?

In the 19th century, passenger pigeons were so numerous that hunters competed to shoot as many as possible. But the last passenger pigeon died in the Cincinnati Zoo over 100 years ago. How did it all go so wrong?

Meteor lit up Michigan night skies

A brilliant fireball lit up skies in the U.S. state of Michigan Tuesday night and caused the equivalent of a magnitude 2.0 earthquake.

Is Arctic warming behind year’s crazy winter weather?

An atmospheric scientist who studies the Arctic explains why – because of global warming – the U.S. may be in for longer cold spells in the winter.

What was that bright flash over Russia?

A flash seen over a wide swath of Russia on January 7 at first caused fears of a U.S. air strike on North Korea. For now, the flash is unexplained.

Genetic research reveals secrets of extinct Tasmanian tigers

The most complete genome yet for a truly unique marsupial - the Tasmanian tiger - suggests that, if the tigers hadn't been hunted to extinction, they might still have struggled to survive.

NASA spacecraft spies electric-blue clouds over Antarctica

These noctilucent, or night-shining, clouds are seeded by debris from disintegrating meteors. They glow electric blue when they reflect sunlight.

Ocean plastic killing marine turtles

Hundreds of marine turtles die every year after getting tangled in trash - such as plastic ‘six pack’ holders and discarded fishing gear - in oceans and on beaches.

How deep is your snow?

It’s really hard to measure snowfall accurately. The National Weather Service relies on more than 8,000 volunteers with rulers.

See it! High tides and winter storms

High tides followed Monday's supermoon, as Storm Eleanor plowed into Europe. Then a "bomb cyclone" hit the U.S. East Coast. Photos here showing winter's power and terrible beauty.