Atlantic overturning is weakest it has been in over 1000 years

A new study suggests that the Atlantic warming is the weakest it has been in over 1000 years.

Tyler MacDonald | Apr 11, 2018

The Atlantic overturning is one of the Earth's most important heat transport systems, pumping warm water northward and cold water southwards. Now, new data suggests that it is weaker today than it has been in more than 1000 years, according to Phys.org.

The study reveals that it has slowed down by approximately 15 percent since the middle of the 20th century, and man-made climate change is the suspected cause.

"We detected a specific pattern of ocean cooling south of Greenland and unusual warming off the US coastwhich is highly characteristic for a slowdown of the Atlantic overturning, also called the Gulf Stream System," said Levke Caesar, lead author of the study. "It is practically like a fingerprint of a weakening of these ocean currents."

When currents slow down, they transport less heat to the north, which leads to widespread cooling of the northern Atlantic. This is the only ocean region that has cooled down despite global warming. But at the same time, the Gulf Stream shifts northward and closer to shore, warming the waters that line the northern half of the US Atlantic coast.

"That region has warmed faster than most other parts of the world ocean in recent decades," said Vincent Saba, co-author of the study. "This specific ocean temperature pattern has been projected by high-resolution computer simulations as a response to rising carbon dioxide levels in the atmospherenow it has been confirmed by measurements."

The current warming trend stems from fossil fuel greenhouse gases and has been happening since 1950. It is a global warming larger than any time in the history of human civilization, and one that scientists are continuously looking for solutions to.

The findings were published in Nature.