FYI. Best, Emily. NOAA scientist sees 'negligible' cooling impact from volcano (04/21/2010)
Lauren Morello, E&E reporter The ongoing eruption of Iceland's Eyjafjallajökull volcano appears unlikely to have a significant immediate cooling effect on Earth's climate, a top federal scientist said yesterday. "Right now, we can say the impact on climate is not clear at this time," said Chester Koblinsky, who directs the National Oceanic and Atmospheric Administration's Climate Program Office. "However, the basic parameters of this volcano to date suggest a negligible impact in the sense of cooling global temperatures." Contrast that with the 1991 eruption of Mount Pinatubo in the Philippines. That blast sent 10 million tons of sulfur into the stratosphere, where the particles helped block sunlight. They cooled the Earth's surface about 1 degree Fahrenheit for roughly a year. But the Iceland volcano is unlikely to have a similar effect in part because of its location. Although its ash plume has shut down air traffic in broad swaths of Europe, atmospheric circulation patterns make it unlikely the volcano's ash will spread worldwide. "History shows us that volcanoes at lower latitudes -- such as those in the tropical belts, like Pinatubo -- have a much greater impact," Koblinsky said. "High-latitude volcanoes tend to have their material confined to higher latitudes, and so the impact doesn't tend to be global." More importantly, the Iceland volcano also ranks low on the "explosive index," the scale scientists use to compare eruptions. The scale, which goes from 0 to 8, ranks eruptions by the amount of ash they produce, the height the ash reaches in the atmosphere and other factors. The 1991 Mount Pinatubo blast rates a 6, while the 1980 Mount Saint Helens blast in Washington state earns a 5. In contrast, the Iceland eruption now appears to rank between 2 and 3, Koblinsky said. In practical terms, that means its ash is not reaching high enough into the atmosphere to cool the planet. Koblinsky said ash would have to reach a height of 10,500 meters -- or about 33,000 feet -- into the stratosphere. But ongoing measurements show the Iceland volcano's ash reached under 10,000 meters on April 14, then fell to 8,000 meters on April 14 and now hovers around 6,000 meters. Still, Koblinsky said he couldn't completely rule out the idea the volcano could have some measurable impact on the future climate, including extra cloud formation in some areas that could affect rain and snowfall patterns. Tony Hall, director of NOAA's Alaska Volcanic Ash Advisory Center, said his agency is still keeping a close eye on the Iceland eruption. "The volcano is still erupting, so we're still monitoring," he said. "All of these volcanoes have their own personality, and behavior sometimes is a little difficult to predict." _______________________________________________ -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
