The impact of the Eyjafjallajökull volcano is likely to be “virtually non-existent” on the global climate because the eruption is too small and gases are not penetrating the upper atmosphere, Blair Trewin, a senior climatologist at Australia’s National Climate Centre in Melbourne, said in an interview.

“In its current form, we wouldn’t expect the eruption to have any significant global climate effects,” Trewin said today by telephone. “In terms of how much material was being put up into the atmosphere, Pinatubo was several hundred times larger than this has been so far.”[ Bloomberg News ]

Will the Iceland Volcano effect global climate?

The biggest volcanic eruptions can lower the earth’s temperature for a few years because sulfuric gases they produce can absorb and reflect back the sun’s radiation, according to NASA. Pinatubo lofted about 20 million tons of sulfur dioxide into the stratosphere, causing global temperatures to drop by about 1 degree Fahrenheit (0.6 degrees Celsius) until 1993, according to the U.S. Geological Survey.  

Iceland Volcano - 81,000 Flights Cancelled

The ice-covered Icelandic volcano erupted for the second time in four weeks on April 14, spewing ash across Europe’s airspace and causing cancellation of as many as 81,000 flights. An estimated 750 tons of volcanic material was released into the air every second from the 5,466-foot mountain, according to the Icelandic Institute of Earth Sciences’ Web site.

The Pinatubo eruption, which killed as many as 800 people and left 100,000 homeless, had a greater impact on the environment because it lay close to the equator, Trewin said. Air flows in the upper atmosphere from the equator to the poles, meaning Pinatubo’s gases spread over the whole globe, he said.

That wouldn’t be the case with Iceland because of its northern latitude, he said.

Iceland’s volcanic eruption is “much smaller” than Pinatubo, Michael Zemp, a glaciologist with the World Glacier Monitoring Service at the University of Zurich, said today in a telephone interview. Information from colleagues in Iceland indicates “it’s a short-term thing” that is unlikely to have as profound effect as Pinatubo.

Gas, Dust Debrisfrom Iceland Volcano

Eyjafjallajökull is throwing gas, dust and other debris about 12,000 feet (3,650 meters) to 15,000 feet into the air, below the 30,000-feet threshold where ash could reduce temperatures, Elwynn Taylor, an agricultural meteorologist at Iowa State University in Ames, said in an interview last week.

“Volcanic material will only have a longer-term impact on the climate if it gets into the upper atmosphere above rain clouds, otherwise it just gets rained out in a few days,” Trewin said today.

“It goes wherever the wind carries it,” Gudrun Larsen, a volcano expert with the University of Iceland’s Institute of Earth Sciences, said today in an e-mail.

Emissions that reach 10,000 meters into the atmosphere or higher can have an impact on global climate, said Eva Bauer, a researcher at the Potsdam Institute for Climate Impact Research, in an interview. More turbulent seasons including winter and spring will also result in longer-term climate effects from volcanic eruptions, she added.

The German Aerospace Center is preparing today to fly over the volcano with a specially equipped Dassault Aviation SA-made Falcon 20E airplane to measure the amount and quality of ash in the air, Director Johann-Dietrich Woerner said on the group’s Web site. Scientists at the center are currently measuring and assessing the effects of the eruption on the atmosphere using satellites.

Iceland Volcano - ‘Global Air Polluters’

“Volcanoes are global air polluters,” said Michael Bittner, an atmospheric researcher at the center, on its Web site. “Volcanic eruptions can have continental or global atmospheric effects, not only regional ones.”

Around the world, 18 volcanoes are currently active including three in Russia’s Kamchatka peninsula, one in Hawaii and one in Alaska, according to the Smithsonian Institution’s Global Volcanism Program.

This year, 39 volcanoes have erupted, including Yasur on the island of Vanuatu, the institute’s Web site said.

Scientific forecasts for the Icelandic volcano have varied.

Haraldur Eiriksson, a meteorologist at Iceland’s meteorological office, has predicted little change in the ash pattern in Europe at least through April 23.

Sigrun Hreinsdottir, a geophysicist at the University of Iceland in Reykjavik, said volcanic eruptions may continue for months and curtail European air traffic.

The Associated Press reported today that the eruption and the towering column of ash spewing out of it have already declined significantly, citing Icelandic seismologist Bryndis Brandsdottir of the University of Iceland, who based her estimates on seismological radar readings in Reykjavik.