News tagged with northern hemisphere

When the Sahara turned to sand

The Sahara wasn't always a desert. Trees and grasslands dominated the landscape from roughly 10,000 years ago to 5,000 years ago. Then, abruptly, the climate changed, and north Africa began to dry out.

Nov 11, 2013 4.4 / 5 (12) 4

How to foresee US heat waves

Scientists have fingerprinted a distinctive atmospheric wave pattern high above the Northern Hemisphere that can foreshadow the emergence of summertime heat waves in the United States more than two weeks ...

Oct 27, 2013 4.5 / 5 (6) 2 | with audio podcast

Tackling an Ice Age mystery

In the northern hemisphere, ice sheets ebb and flow in 100,000-year cycles, driven by varying amounts of sunlight falling on Earth's surface as its orbit and orientation toward the sun changes. But astronomical variations ...

Sep 05, 2013 4.8 / 5 (5) 0