Does a green sky predict a tornado?

Sometimes, before a tornado strikes, the sky turns an eerie green color. The answer to why the sky is blue will help you understand why the sky is sometimes green before bad weather.

Map of China with moving blob of orange.

Air pollution returning to pre-Covid levels

In early 2020, satellite data showed a decline in air pollution coinciding with Covid lockdowns. One year later, as lockdown restrictions loosen and regular activity resumes, air pollution is bouncing back to pre-Covid levels.

Small glacier in the middle of a lake.

Scientists stunned to discover plants beneath mile-deep Greenland ice

Fossilized plants found in the rocks and soil beneath Greenland ice suggests the ice melted at some point in the last million years and may do so again.

Close-up of white blossoms covered in snow.

How plants manage the shift from winter to spring

How plants tolerate cold spells, and the effects of climate change on how plants manage the transition from winter to spring.

Torrential rains drench Hawaii

A strong tropical depression picking up moisture from the warm ocean caused widespread flooding in the Hawaiian islands.

A round planet covered with blue ocean with white clouds, in a field of stars.

Was ancient Earth a water world?

Earlier studies have suggested the possibility that Earth was once covered with water. New evidence – focused on Earth’s mantle – suggests our planet was a true water world, covered by a global ocean, billions of years ago.

Aerial view of blue river winding through green forested landscape.

Climate change altering Earth’s rivers

A new study suggests that climate change is the key driver of changes in water flow in rivers worldwide.

Irregular yellow shapes with red spots on them.

How Antarctica was linked to old Gondwana neighbors

A new animation illustrates how Antarctica was linked to its ancient neighbors – today’s Australia, India and South Africa – as part of the ancient Gondwana supercontinent.

Large winged insect with big red eyes on a twig.

Billions of cicadas may be coming soon to trees near you

One of the largest groups of 17-year cicadas, Brood X, last emerged from underground in 2004. The next generation will begin arriving in April 2021.

Smoke from a wildfire behind mountains, truck on road in foreground.

Small temperature increase can cause bigger wildfires, more often

A new study shows that just a half a degree of global temperature rise markedly increases fire danger on the most widely inhabited continents.