Oceans may explain slowdown in climate change: study
By Environment Correspondent Alister Doyle | Reuters – 5 hrs ago
By Environment Correspondent Alister Doyle
OSLO (Reuters) - Climate change
could get worse quickly if huge amounts of extra heat absorbed by the
oceans are released back into the air, scientists said after unveiling
new research showing that oceans have helped mitigate the effects of
warming since 2000.
Heat-trapping gases are being emitted into the
atmosphere faster than ever, and the 10 hottest years since records
began have all taken place since 1998. But the rate at which the earth's
surface is heating up has slowed somewhat since 2000, causing
scientists to search for an explanation for the pause.Experts in France and Spain said on Sunday that the oceans took up more warmth from the air around 2000. That would help explain the slowdown in surface warming but would also suggest that the pause may be only temporary and brief.
"Most of this
excess energy was absorbed in the top 700 meters (2,300 ft) of the ocean
at the onset of the warming pause, 65 percent of it in the tropical
Pacific and Atlantic oceans," they wrote in the journal Nature Climate Change.
Lead author Virginie Guemas of the Catalan Institute of Climate Sciences in Barcelona said the hidden heat may return to the atmosphere in the next decade, stoking warming again.
"If it is only related to natural variability then the rate of warming will increase soon," she told Reuters.
Caroline Katsman of the Royal Netherlands Meteorological Institute,
an expert who was not involved in the latest study, said heat absorbed
by the ocean will come back into the atmosphere if it is part of an
ocean cycle such as the "El Nino" warming and "La Nina" cooling events
in the Pacific.
She said the study
broadly confirmed earlier research by her institute but that it was
unlikely to be the full explanation of the warming pause at the surface,
since it only applied to the onset of the slowdown around 2000.
THRESHOLDThe pace of climate change has big economic implications since almost 200 governments agreed in 2010 to limit surface warming to less than 2 degrees Celsius (3.6 F) above pre-industrial levels, mainly by shifting from fossil fuels.
Surface temperatures have already risen by 0.8 C. Two degrees is widely seen as a threshold for dangerous changes such as more droughts, mudslides, floods and rising sea levels.
Some governments, and skeptics that man-made climate change is a big problem, argue that the slowdown in the rising trend shows less urgency to act. Governments have agreed to work out, by the end of 2015, a global deal to combat climate change.
Last year was ninth warmest since records began in the 1850s, according to the U.N.'s World Meteorological Organization, and 2010 was the warmest, just ahead of 1998. Apart from 1998, the 10 hottest years have all been since 2000.
Guemas's study, twinning observations and computer
models, showed that natural La Nina weather events in the Pacific around
the year 2000 brought cool waters to the surface that absorbed more
heat from the air. In another set of natural variations, the Atlantic
also soaked up more heat."Global warming is continuing but it's being manifested in somewhat different ways," said Kevin Trenberth, of the U.S. National Center for Atmospheric Research. Warming can go, for instance, to the air, water, land or to melting ice and snow.
Warmth is spreading to ever deeper ocean levels, he said, adding that pauses in surface warming could last 15-20 years.
"Recent warming rates of the waters below 700 meters appear to be unprecedented," he and colleagues wrote in a study last month in the journal Geophysical Research Letters.
The U.N. panel of climate scientists says it is at least 90 percent certain that human activities - rather than natural variations in the climate - are the main cause of warming in recent decades.
(Reporting by Alister Doyle, Environment Correspondent; Editing by Peter Graff)
end quote from:
http://news.yahoo.com/oceans-may-explain-slowdown-climate-change-study-170410831.html
The way I've heard it explained is it is sort of like when on a hot day you have ice in your fountain drink. As long as there is ice in the drink the drink stays fairly cold. But as soon as the ice is all melted the drink heats up very fast. The ocean air heating system of earth is exactly like this. So when we need to watch out is when the ice is all or mostly gone every 6 months on either the north or south pole. I suppose one way to deal with this as a human might be eventually to switch hemispheres whenever the weather gets too crazy during one time of the year or another in either hemisphere.
1 comment:
The elephant in the room here, not discussed, is that as the ocean warms up at 700 meters depth, that impacts the stability of the massive offshore deposits of methane hydrate buried under shallow sediments along the edges of all of the continental shelves. If that bcomes destabilized by warming oceans, it could set off the "mother of all greenhouse gas feedback loops."
Post a Comment