Originally published August 3 2012
Chronic drought, extreme weather patterns 'the new normal,' researchers say
by J. D. Heyes
(NaturalNews) Summer this year not quite the paradise you anticipated? Has the heat got you beat? Well, get used to it, say some researchers who claim that, based on key evidence, current climate conditions could become the "new normal."
A group of 10 researchers from Oregon State University, who published their recent findings in the journal Nature Geoscience, said their findings indicate that the western part of North America suffered a chronic drought from 2000-2004, which led to the death of some forests and caused river basins to dry up.
The period, which they said was the strongest drought in eight centuries, could become stereotypical in the coming years, while now could become "the good old days."
The researchers said such climatic extremes are the result of global warming, and that today's weather, decades from now, will seem moderate in comparison. Climate models and precipitation projections, the team said, indicate that the current period will be close to the "wet end" of an overall drier hydroclimate during the last half of the 21st century.
"Climatic extremes such as this will cause more large-scale droughts and forest mortality, and the ability of vegetation to sequester carbon is going to decline," said Beverly Law, a co-author of the study and a professor of global change biology and terrestrial systems science at Oregon State.
"During this drought, carbon sequestration from this region was reduced by half," she said. "That's a huge drop. And if global carbon emissions don't come down, the future will be even worse."
Drought conditions to stay the same, or worsen?
In addition to extreme damage wrought by the 2000-2004 drought on the environment, the researcher team said, it also managed to cut carbon sequestration by more than half across a large swath of Canada, the U.S. and Mexico.
It wasn't clear; however, if the current drought gripping the Midwest and surrounding regions - half of all U.S. counties have now been declared disaster areas by the Department of Agriculture because of high temperatures - is related to the same forces of nature, said Law. That's because her team's study did not address that potential relationship, and there are some climate mechanisms in North American that affect the Midwest more than other parts of the country.
But, she noted, her team cannot be certain about the western portion of the country. That's because tree-ring data show that the last two periods of similar drought conditions took place in the Middle Ages, from 977-981 and 1146-1151.
Law said ordinarily the land sink in North America is able to sequester about 30 percent of carbon emitted into the atmosphere as a result of the burning of fossil fuels in the same region. But based on projected precipitation changes and the severity of drought, some scientists believe that this carbon sink - a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period - in the western part of North America could eventually disappear by the end of the century.
Those were the days...
"Areas that are already dry in the West are expected to get drier," said Law. "We expect more extremes. And it's these extreme periods that can really cause ecosystem damage, lead to climate-induced mortality of forests, and may cause some areas to convert from forest into shrublands or grassland."
The team said such effects are driven by human-caused activities, which increase global temperatures, and associated loss of soil moisture and decreased run-off in all major water basins in the western United States.
While regional precipitation patterns are difficult to forecast, the team's report said current climate models may be underestimating the extent and severity of drought. The researchers predict that in 80 of the 95 years, between 2006-2100, precipitation levels will be as low or lower than this "turn-of-the-century" drought from 2000-2004.
Towards the latter half of the 21st century the precipitation regime associated with the turn of the century drought will represent an outlier of extreme wetness," the team wrote in their study, adding long-term trends are consistent with a 21st century "megadrought."
Sources:
http://planetsave.com
http://newsroomamerica.com
http://www.naturalnews.com/drought.html
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