Climate Change News
Published on Jul 17, 2017
How Climate Change Could Jam The World’s Ocean Circulation: climate change science, biology, experiment, environment, glacier, climate control, Temperature, Carbon dioxide, earth weather.
How Climate Change Could Jam The World’s Ocean Circulation
Scientists are closely monitoring a key current in the North Atlantic to see if rising sea temperatures and increased freshwater from melting ice are altering the “ocean conveyor belt” — a vast oceanic stream that plays a major role in the global climate system.
Susan Lozier is having a busy year. From May to September, her oceanographic team is making five research cruises across the North Atlantic, hauling up dozens of moored instruments that track currents far beneath the surface. The data they retrieve will be the first complete set documenting how North Atlantic waters are shifting — and should help solve the mystery of whether there is a long-term slowdown in ocean circulation. “We have a lot of people very interested in the data,” says Lozier, a physical oceanographer at Duke University.
A similar string of moorings across the middle of the Atlantic, delving as deep as 3.7 miles from the Canary Islands to the Bahamas, has already detected a disturbing drop in this ocean’s massive circulation pattern. Since those moorings were installed in 2004, they have seen the Atlantic current wobble and weaken by as much as 30 percent, turning down the dial on a dramatic heat pump that transports warmth toward northern Europe. Turn that dial down too much and Europe will go into a deep chill.
Researchers have been worried about an Atlantic slowdown for years. The Atlantic serves as the engine for the planet’s conveyor belt of ocean currents: The massive amount of cooler water that sinks in the North Atlantic stirs up that entire ocean and drives currents in the Southern and Pacific oceans, too. “It is the key component” in global circulation, says Ellen Martin, a paleoclimate and ocean current researcher at the University of Florida. So when the Atlantic turns sluggish, it has worldwide impacts: The entire Northern Hemisphere cools, Indian and Asian monsoon areas dry up, North Atlantic storms get amplified, and less ocean mixing results in less plankton and other life in the sea.
A single Atlantic Ocean current system accounts for up to a quarter of the planet’s heat flux.
Paleoclimatologists have spotted times in the deep past when the current slowed quickly and dramatically, cooling Europe by 5 to 10 degrees C (10 to 20 degrees F) and causing far-reaching impacts on climate. Modelers have tried to predict how human-caused climate change might impact the Atlantic current, and how its slowdown might muck with the world’s weather even more. But years of intensive peering at this question haven’t yet provided much clarity.
Now, debate is raging about whether the recent Atlantic slowdown has been triggered by climate change, or is just part of a normal cycle of fast and slow currents. New studies in the last few years and months have come out supporting both prospects. The new data from the north, Lozier and others hope, might help to sort things out…