Everything Is Hitched, the Vertical Edition

Periodic changes in winds in the stratosphere – 15 to 30 miles above us – influence mile-deep ocean circulation patterns, and with it, global climate.

According to OurAmazingPlanet, a team at the University of Utah and Germany’s Max Planck Institute for Meteorology “used weather observations and 4,000 years' worth of supercomputer simulations of climate conditions to show that high-altitude Arctic winds affect the speed of the Gulf Stream, the ocean current that transports warm surface waters from lower latitudes into the North Atlantic, where they cool, sink and return south. This ‘conveyor belt’ affects the whole world's ocean circulation and climate. But the conveyor belt has a weak spot in the North Atlantic, south of Greenland, where sinking or ‘down-welling’ occurs. ... If the water is close to becoming heavy enough to sink, then even small additional amounts of heating or cooling from the atmosphere can speed or slow this process.” 

“We found evidence that what happens in the stratosphere matters for the ocean circulation and therefore for climate,” says Thomas Reichler, Associate Professor Department of Atmospheric Sciences at the University of Utah and senior author of the study, which was published Sunday in the journal Nature Geoscience. “If we as humans modify the stratosphere, it may – through the chain of events we demonstrate in this study – also impact the ocean circulation,” Reichler says. “Good examples of how we modify the stratosphere are the ozone hole and also fossil-fuel burning that adds carbon dioxide to the stratosphere. These changes to the stratosphere can alter the ocean, and any change to the ocean is extremely important to global climate.”

What it means for climate research? More variables in the mix. “Our analyses identify a previously unknown source for decadal climate variability and suggest that simulations of deep layers of the atmosphere and the ocean are needed for realistic predictions of climate,” conclude the study’s authors.

Image by Thomas Reichler, University of Utah.

Reed McManus is a senior editor at Sierra. He has worked on the magazine since Ronald Reagan’s second term. For inspiration, he turns to cartoonist R. Crumb’s Mr. Natural, who famously noted: “Twas ever thus.”