Global warming is now slowing down the circulation of the oceans — with potentially dire consequences
Global warming is now slowing down the circulation of the oceans — with potentially dire consequences
http://www.washingtonpost.com/news/ener ... sequences/
Welcome to this week’s installment of “Don’t Mess with Geophysics.”
Last week, we learned about the possible destabilization of the Totten Glacier of East Antarctica, which could unleash over 11 feet of sea level rise in coming centuries.
And now this week brings news of another potential mega-scale perturbation. According to a new study just out in Nature Climate Change by Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research and a group of co-authors, we’re now seeing a slowdown of the great ocean circulation that, among other planetary roles, helps to partly drive the Gulf Stream off the U.S. east coast. The consequences could be dire – including significant extra sea level rise for coastal cities like New York and Boston.....
New Simulations Question the Gulf Stream’s Role in Tempering Europe’s Winters
It's the flow of warm tropical water across the Atlantic that keeps European winters mild, right? Maybe not
Jan 15, 2013 |By Stephen C. Riser and M. Susan Lozier
Three new climate studies indicate that our long-held belief about the Gulf Stream's role in tempering Europe's winters may not be correct. Yet the studies themselves do not agree.
Two of the three studies ascribe a surprisingly large role to the direction of the prevailing winds, and one focuses on the heat lost from the ocean.
Many climate models indicate that extensive melting of Arctic ice would not actually shut down the Gulf Stream, as previously thought.
The ocean's influence on climate in Europe and elsewhere should become clearer within a decade, now that a global array of more than 3,000 floating ocean sensors called Argo is making near-real-time maps of temperature and salinity down to 2,000 meters.
For a century, schoolchildren have been taught that the massive ocean current known as the Gulf Stream carries warm water from the tropical Atlantic Ocean to northwestern Europe. As it arrives, the water heats the air above it. That air moves inland, making winter days in Europe milder than they are in the northeastern U.S.
It might be time to retire that tidy story. The explosion of interest in global climate has prompted scientists to closely study the climatic effects of the Gulf Stream only to discover that those effects are not as clear as conventional wisdom might suggest. Based on modeling work and ocean data, new explanations have emerged for why winter in northern Europe is generally less bitter than winter at the same latitudes in the northeastern U.S. and Canada—and the models differ on the Gulf Stream's role. One of the explanations also provides insight into why winter in the U.S. Northwest is warmer than it is across the Pacific in eastern Russia.
At the same time, recent studies have been casting doubt on the popular conjecture made a few years ago that melting of Arctic ice could “shut down” the Gulf Stream, thereby wreaking havoc with Europe's weather. Yet the studies do suggest that climate change could at least affect the strength of the Gulf Stream, which could lessen the impact of global warming on northern Europe.
Competing Theories......
more: http://www.scientificamerican.com/artic ... s-winters/
Incessant mountain rain, snow and melting glaciers in a comparatively small region of land that hugs the southern Alaska coast and empties fresh water into the Gulf of Alaska would create the sixth largest coastal river in the world if it emerged as a single stream, a recent study shows.
The collective fresh water discharge of this region is more than four times greater than the mighty Yukon River of Alaska and Canada, and half again as much as the Mississippi River, which drains all or part of 31 states and a land mass more than six times as large.
"Freshwater runoff of this magnitude can influence marine biology, nearshore oceanographic studies of temperature and salinity, ocean currents, sea level and other issues," said David Hill, lead author of the research and an associate professor in the College of Engineering at Oregon State University.
This is one of the first studies to accurately document the amount of water being contributed by melting glaciers, which add about 57 cubic kilometers of water a year to the estimated 792 cubic kilometers produced by annual precipitation in this region. The combination of glacial melt and precipitation produce an amount of water that's larger than many of the world's great rivers, such as the Ganges, Nile, Volga, Niger, Columbia, Danube or Yellow River.
dissident wrote:The cold SST anomaly is also interacting with the atmospheric storm tracks. The storm tracks are pseudo-organized paths for baroclinic eddies and exhibit a dynamics of their own. The North Atlantic anomaly is like a topographic feature (geopotential height anomaly) that the Rossby waves at the core of the synoptic scale circulation respond to.
I wouldn't be surprised if the ridiculously persistent flow pattern we had this winter with abnormally cold temperatures persisting into March is due to the cooling over the Atlantic.
Ibon wrote:I am glad we all didn't die from Ebola so we can now watch this new crisis unfold.
Newfie wrote:Ibon wrote:I am glad we all didn't die from Ebola so we can now watch this new crisis unfold.
Is this Ibon speaking? Or are you simply channeling the OP.
yellowcanoe wrote: I am really wondering if next winter is going to be even colder than this one was.
yellowcanoe wrote:You could sell me on the mini ice age idea. Each of our last four winters has been colder than the previous one. This February was the coldest on record. Open fields are still snow covered even though we had less snow than normal this winter. Daily temperatures continue to average well below normal. Yesterday started off at -17 C and I had to dress the way I would in January for the bike ride to work. I have no memory of having to dress so warmly at the end of March in any previous year. I am really wondering if next winter is going to be even colder than this one was.
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