Click For Photo: https://scx2.b-cdn.net/gfx/news/2019/switchingont.jpg
34 million years ago, the warm greenhouse climate of the dinosaur age ended, and the colder icehouse climate of today commenced. Antarctica glaciated first, and geological data imply that the Atlantic meridional overturning circulation, the global ocean conveyor belt of heat and nutrients warm Europe, also started at this time. Why, exactly, has remained a mystery.
"We have found a new trigger to explain the start-up of the Atlantic current system during the greenhouse-icehouse climate transition: During the warm climate, buoyant fresh water flooded out of the Arctic and prevented the ocean sinking that helps power the conveyor. We found that the Arctic-Atlantic gateway closed due to tectonic forces, causing a dramatic increase in North Atlantic salinity. This caused warming of the North Atlantic and Europe, and kick-started the modern circulation that keeps Europe warm today," says David Hutchinson, researcher at the Department of Geological Sciences, Stockholm University, and lead author of the article published in Nature Communications.
Team - Scientists - Bolin - Centre - Climate
The team of scientists, from the Bolin Centre for Climate Research, used a combination of geophysical data and climate modeling to show that the freshwater transport through the Arctic-Atlantic gateway plays a critical role in controlling the overturning circulation.
"Not only did deep water start forming in the Atlantic Ocean, it...
Wake Up To Breaking News!