Posted by Co2sceptic on Oct 1st 2012
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Runaway global warming gets more negative feedback

Salt marshes and similar types of coastal terrain could act naturally to fight global warming by absorbing increasing amounts of carbon in a warming world, scientists have found. Even better, salt marshes' carbon-sequestering effects would actually be increased sea-level rise.

Salt marshes, mainly made up of specialised grasses and their root systems, are a common type of coastal environment. They trap silt, serving to build up the elevation of the coastline and so resist storms and flooding. As the seas rise, the marsh rises too, as professor Matt Kirwan (Virginia uni) explains:

“One of the cool things about salt marshes is that they are perhaps the best example of an ecosystem that actually depends on carbon accumulation to survive climate change: The accumulation of roots in the soil builds their elevation, keeping the plants above the water,” says the prof.

According to a statement announcing Kirwan and his colleagues' new research into salt-marsh carbon effects:


Salt marshes store enormous quantities of carbon, essential to plant productivity, by, in essence, breathing in the atmospheric carbon and then using it to grow, flourish and increase the height of the soil. Even as the grasses die, the carbon remains trapped in the sediment. The researchers’ model predicts that under faster sea-level rise rates, salt marshes could bury up to four times as much carbon as they do now.

Click source to read FULL report from Lewis Page

Also read this "Reply to Article" from Charles Battig

UVA Today

Senior News Officer

Mr. Samarrai,

Your article, Salt Marsh Carbon May Play Role in Slowing Climate Warming, Study Shows, contains statements regarding the mechanics of climate and carbon dioxide interactions which suggest a lack of understanding and scientific knowledge on your part. By doing so you cast needless doubt on the accuracy of the remainder of the article, the work of the researchers whom you depict, and the UVA Today image .

Carbon dioxide is not the "predominant" greenhouse gas as you claim. Water vapor is the primary greenhouse gas and is understood to account for approximately 95% of the greenhouse gas effect. Carbon dioxide makes up about 3.6 percent of the effect. The fraction of total carbon dioxide generated that is attributable to human activity is estimated at 3.22 percent. Thus human activity is estimated to contribute about 0.117 percent of the greenhouse effect...a long way from being "predominant." "A large portion of the carbon dioxide in the atmosphere is produced by human activities"...NOT.

"A warmer climate melts polar ice, causing sea levels to rise." Do you understand that there are two poles? If you are speaking of North polar ice (Arctic), it could all melt, as it has in the past, and there would be no change in sea level (try Googling Archimedes). The Antarctic (pole) has been adding to its total ice mass.

There has been no increase in atmospheric global temperatures for 12+ years; the rate-of-rise of sea level has recently stalled, and the longer term rate-of-rise remains stable at approximately 10-12 inches per century.

Does your "generally accepted scientific theory" include solar, solar radiation wavelength, and cosmic particle interactions?

I find it regrettable that such errors pass your editorial board.

Yours truly,


Charles Battig, MD

VA-Scientists and Engineers for Energy and Environment

Charlottesville


Original article:

Salt Marsh Carbon May Play Role in Slowing Climate Warming, Study Shows - Fariss Samarrai - news.virginia.edu

A warming climate and rising seas will enable salt marshes to more rapidly capture and remove carbon dioxide from the atmosphere, possibly playing a role in slowing the rate of climate change, according to a new study led by a University of Virginia environmental scientist and published in the Sept. 27 issue of the journal Nature.

Carbon dioxide is the predominant so-called “greenhouse gas” that acts as sort of an atmospheric blanket, trapping the Earth’s heat. Over time, an abundance of carbon dioxide can change the global climate, according to generally accepted scientific theory. A warmer climate melts polar ice, causing sea levels to rise.

A large portion of the carbon dioxide in the atmosphere is produced by human activities, primarily the burning of fossil fuels to energize a rapidly growing world human population.

“We predict that marshes will absorb some of that carbon dioxide, and if other coastal ecosystems – such as seagrasses and mangroves – respond similarly, there might be a little less warming,” said the study’s lead author, Matt Kirwan, a research assistant professor of environmental sciences in the College of Arts & Sciences.

Salt marshes, made up primarily of grasses, are important coastal ecosystems, helping to protect shorelines from storms and providing habitat for a diverse range of wildlife, from birds to mammals, shell- and fin-fishes and mollusks. They also build up coastal elevations by trapping sediment during floods, and produce new soil from roots and decaying organic matter.

“One of the cool things about salt marshes is that they are perhaps the best example of an ecosystem that actually depends on carbon accumulation to survive climate change: The accumulation of roots in the soil builds their elevation, keeping the plants above the water,” Kirwan said.

Salt marshes store enormous quantities of carbon, essential to plant productivity, by, in essence, breathing in the atmospheric carbon and then using it to grow, flourish and increase the height of the soil. Even as the grasses die, the carbon remains trapped in the sediment. The researchers’ model predicts that under faster sea-level rise rates, salt marshes could bury up to four times as much carbon as they do now.

“Our work indicates that the value of these ecosystems in capturing atmospheric carbon might become much more important in the future, as the climate warms,” Kirwan said.

But the study also shows that marshes can survive only moderate rates of sea level rise. If seas rise too quickly, the marshes could not increase their elevations at a rate rapid enough to stay above the rising water. And if marshes were to be overcome by fast-rising seas, they no longer could provide the carbon storage capacity that otherwise would help slow climate warming and the resulting rising water.

“At fast levels of sea level rise, no realistic amount of carbon accumulation will help them survive,” Kirwan noted.

Kirwan and his co-author, Simon Mudd, a geosciences researcher at the University of Edinburgh in Scotland, used computer models to predict salt marsh growth rates under different climate change and sea-level scenarios.

The United States Geological Survey’s Global Change Research Program supported the research.