Volcanoes and Climate Change

The impact of volcanic eruptions on global warming could provide a new explanation for the so-called 'pause' in climate change. According to a recent study, models for predicting the rate at which temperatures around the world would rise from 1998 onwards did not take into consideration the measurable impact volcanoes can have. Rather than contributing to global warming, eruptions release particles into the air that reflect sunlight--causing temperatures to drop. This phenomenon was not taken into account when predictions were made--offering an explanation for why the world seemed to stop heating up. (1)

Some examples: • Mount Laki is a large volcano in Iceland that has a history of producing climate changing eruptions. In 1783, Laki erupted, releasing vast rivers of lava. The explosive eruption was so violent that ash and sulfur dioxide were injected into the stratosphere some 8 miles up. This cloud was then swept around the world by stratospheric winds. The result was a significant decrease in the amount of sunlight reaching the earth's surface for several years. That reduction in sunlight brought about bitter cold weather across the northern hemisphere. The winter of 1784 was one of the coldest ever seen in New England and in Europe. The Mississippi river froze all the way down to New Orleans. Historical records show that similar conditions existed during the following winter. (2) • Mount Tambora in Indonesia erupted with cataclysmic force in April 1815. It was the largest volcanic eruption in over 1,600 years. It was also during a time of very low solar activity known as the 'Dalton Minimum.' The following year was called 'the year without a summer.' During early June of 1815, a foot of snow fell on Quebec City. In July and August, lake and river ice were observed as far south as Pennsylvania. Frost killed crops across New England with resulting famine. During the brutal winter of 1816/17, the temperature fell to -32 F in New York city. (2) • Krakatoa in Southeast Asia erupted in August 1883 resulting in 36,000 deaths. An estimate of the force of the blast that pounded five cubic miles of volcanic rock into dust is that the explosion equaled somewhere between 10,000 to 30,000 megatons of pure TNT. For comparison purposes, the Hiroshima bomb was 20 kilotons of TNT (note that mega refers to millions of tons, while kilo refers to thousands). After Krakatoa, weather around the world was affected for three years because of dust in the upper atmosphere. (3)

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• In 1991 the second largest volcanic eruption of the 20th century occurred when Mount Pinatubo in the Philippines exploded with enormous force, killing almost 1,000 people and causing widespread damage. Millions of tons of ash and gas were blasted into the atmosphere from the mountain, reaching an altitude of 21 miles. Over the next two years, average temperatures across the whole of the Earth fell by up to 0.5 degrees C. Mount Pinatubo and the earlier major eruption of El Chicon in Mexico in 1982 had important impacts on decadal changes in warming rates. In addition, 17 'small' eruptions occurred after 1999 which had a cumulative effect increasing the reflective effect of aerosols in the upper atmosphere by up to 7% per year from 2000 to 2009. (4) In addition, volcanically induced cooling of the ocean surface penetrated into deeper layers, where it persisted for decades after the event. This remarkable effect on oceanic thermal structure is longer lasting than had previously been suspected and is sufficient to offset a large fraction of ocean warming and sea-level rise supposedly caused by anthropogenic influences. (5) So, where are we today? Based on a literature survey published in 2010, it is reported that volcanic CO2 emissions are much higher than previously estimated, leading to the conclusion that we cannot glibly assume that the increase of atmospheric CO2 is exclusively anthropogenic. (6) Another report states that according to climate scientists, in order to separate human-caused global warming from the 'noise' of purely natural climate fluctuations, temperature records must be at least 17 years long. (7) Don't know how this number was generated and what is so magic about 17 years. Perhaps if all volcanoes stopped, this means that in 17 years, temperatures would start climbing back up. And since 1998 was the magic year when the world stopped heating up, does this mean that in 2015 (1998 plus 17) things will start heating up again? As for volcanoes stopping, a recent National Science Foundation report stated that magma stored for thousands of years in places can erupt in as little as two months. Magma sitting 4-5 kilometers beneath the surface of Oregon's Mount Hood has been stored in near-solid conditions for thousands of years. The time it takes to liquefy and potentially erupt however, is surprisingly short--perhaps as little as a couple of months. (8) Alan Caruba sums this up well, "The fundamental scientific fact that, as opposed to all the nonsense about human control or effect on the Earth's temperatures, volcanoes by comparison render the human component infinitesimal. What Americans need to worry about is the eruption of a super volcano with a large caldera such as the Yellowstone Caldera in Yellowstone National Park and the Valles Caldera in New Mexico. Both have been dormant for thousands of years. (9) And lastly, we can't lay all the blame on volcanoes. As Benjamin Santer has reported, "There is not a single culprit as some scientists have claimed. Multiple factors are implicated. One is the temporary cooling effect of internal climate noise (ongoing climate activity). Other factors are the external cooling influences of the 21st century volcanic activity, an unusually low and long minimum in the last solar cycle, and an uptick in Chines emissions of sulfur dioxide." (7) References

1. Benjamin D. Santer,et al., "Volcanic contribution to decadal changes in tropospheric temperature," Nature Geoscience, 7, 185, 2014
2. Art Horn, "Icelandic volcano: a precursor of global cooling?", energytribune.com, April 19, 2010
3. Ragner Benson, The Greatest Explosions in History, (New York, Carol Publishing Company, 1991), 2
4. Adam Withnall, "Volcanic eruptions contributed to global warming pause scientists claim," independent.co.uk, February 23, 2014
5. P. J. Glecker , et al., "Volcanoes and climate: Krakatoa's signature persists in the ocean," Nature, 439, 675, February 9, 2006 Timothy Casey, "Volcanic carbon dioxide," ISO: 2010, May 17,
6. "Volcanoes contribute to recent warming 'hiatus'", The Independent, February 27, 2014
7. "Volcanoes, including Mount Hood in the US can quickly become active," National Science Foundation, .nsf.gov, February 18, 2014
8. Alan Caruba,"The world's volcanic past and future," factsandfantasy.blogspot.com, February 20, 2014