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Climatologist Says Iceland's Volcanic Ash Cover May Not Cool Planet

by Tanya Thomas on Apr 20 2010 11:20 AM

The volcanic ash cloud that formed as as a result of the Icelandic explosion, an Australian climatologist has said, may not do much to ease global temperatures.

The volcano, which is located under the Eyjafjallajokull glacier, had erupted on April 15, producing a 10-kilometre high plume of ash and rock that extended across most of northern Europe.

And while the particles may have a short-term effect on the local temperature, experts believe that it will not have the same impact as the Pinatubo eruption did two decades earlier.

In June 1991, Mount Pinatubo, an active volcano in the Philippines, launched ten cubic kilometres of material into the atmosphere.

Particles from the eruption entered the Earth's stratosphere resulting in a 10 percent reduction in sunlight reaching the Earth's surface, and a 0.40C drop in global average temperatures.

Dr Blair Trewin of the National Climate Centre in Melbourne says, in its current form the ash cloud is unlikely to have the same impact on global temperatures.

"For a volcano to have a significant global cooling effect it has to get its ash up into the stratosphere," ABC Science quoted him as saying.

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"If it doesn't, the ash will get rained out fairly quickly," he said.

But he said that even if the particles managed to reach the stratosphere, the location of the volcano will mean the ash will likely stay in the northern hemisphere.

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"Once you're in the stratosphere the winds tend to flow out from the equator to the poles," Trewin said.

"So if you get a big eruption in the tropics the winds in the stratosphere will tend to spread out material over the whole globe.

"Whereas if it happens in the polar regions the stuff tends to get stuck - it doesn't spread up to lower latitudes," he stated.

Trewin says the volcanic ash cloud may have an impact locally.

"When Mount St Helens erupted in 1980 it had no significant global impacts, but in the days immediately after the eruption you had cooling of daylight temperatures by 100C or more in some parts of the northwestern United States," he revealed.

Dr Jeff Masters, Director of Meteorology at Weather Underground says the eruption isn't expected to have a significant impact on weather patterns in the northern hemisphere.

"However, the ash could bring spectacular sunsets to Europe over the next week, and to North America by sometime next week, as the jet stream wraps the ash cloud eastwards across the northern hemisphere," he added.

Source-ANI
TAN


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