Did a volcanic eruption induce the summer cooling spell?

September 02, 2013 – RUSSIA – Throughout history, large volcanic eruptions have been known to influence climate. This summer, the Midwest experienced a cold wave referred to as  “Julytober” following the June eruption of Mount Sheveluch in Russia. Experts continue to compare this eruption to others from history and debate whether it could have induced the cooler Midwestern weather. “Large Russian volcano eruptions tend to cool the Midwest,” Historical Climatologist Evelyn Browning-Garriss said. When a volcano erupts, if it is large enough, it can send debris miles into the stratosphere. The stratosphere is the atmosphere above where weather takes place, approximately 6-8 miles off the ground. “Sulfur dioxide combines with water in the atmosphere to provide sulfuric acid aerosol droplets that reflect incoming solar radiation,” PhD Research Geophysicist with the U.S. Geological Survey Alaska Volcano Observatory David Schneider said.Although the eruption of Mount Sheveluch in June was minor compared to previous eruptions like Mount Pinatubo, two years before in 2011 there were two big eruptions in Russia and Iceland. These eruptions launched high amounts of debris into the air that still remain present today. With a lot of debris already existent in the atmosphere, the addition of the debris from Mount Sheveluch may have then had the ability to possibly influence temperatures by blocking out sunlight, Browning-Garriss said. While volcano experts agree that it is possible for an eruption to influence temperature, as observed in the historic “the year without a summer” in 1816 resulting from the disastrous 1815 eruption of Mount Tambora, most do not believe that the June Russian eruption was massive enough to impact temperatures. “It is highly unlikely that the modest eruptions of Mount Sheveluch have contributed in a significant manner,” Schneider said. –Accuweather excerpt