Are major ocean currents moving to turn Earth into a snowball?

A key Atlantic current that warms Europe is weakening, which could lead to a big chill

The Atlantic Meridional Overturning Circulation, or AMOC, ferries warm waters from the tropics northward toward Europe. Recent analyses say the current could weaken by half within 75 years.

Goddard Space Flight Center Scientific Visualization Studio/NASA

Classroom Resources for This Article Classroom Questions Power Words Word Find Puzzle Readability Score: 7.8

One of Earth’s most vital ocean currents is rapidly weakening. The cause: global warming. A collapse of this current could send devastating ripples through the planet’s climate.

The current is known as the Atlantic Meridional Overturning Circulation. Most scientists just call it AMOC. If it were to shut down, the consequences could be catastrophic and far-ranging. In the worst case: Earth’s warming climate could flip to a deep-freeze. Scientists refer to this scenario as a “snowball Earth.”