There’s life in the cold sink yet
In what could be good news for the Earth’s ability to mitigate warming, scientists have reported that deep convection has resumed in the North Atlantic after more than a decade of little activity.
Also known as overturning, deep convection transports cold water to depths of more than 1000m, bringing carbon dioxide with it and keeping the greenhouse gas out the atmosphere for centuries. It's also partly reponsible for maintaining the global climate system, as we know it - at high latitudes, deep convection forms a mass of cold water that drives the Atlantic oceanic conveyor belt and carries warm water northwards.
In the past decade, however, the process of deep convection has been sluggish, causing some to speculate that warming of surface waters due to climate change is already taking its toll on ocean circulation.
Its recent return has now been independently reported by two groups of scientists; the first team, led by Kjetil Våge of the Woods Hole Oceanographic Institution in Massachusetts, publish their data in the latest issue of Nature Geoscience. Igor Yashayaev and John Loder of the Bedford Institute of Oceanography in Nova Scotia, Canada, have a forthcoming paper in Geophysical Research Letters.
Whether it's back for the long haul is anyone's guess. For the full story, my colleague Quirin has an excellent piece on both papers over on Nature News.
Olive Heffernan
