Are Volcanoes Slowing Global Warming?

In 2013, the world pumped 36 billion metric tons (40 billion US tons) of CO2 into the atmosphere through the burning of fossil fuels. Such emissions form a carbon dioxide blanket that allows the sun to penetrate, but prevents much of the surface heat from reflecting back into space. As a result, the oceans are rapidly warming, arctic sea ice is diminishing, and glaciers and the Greenland Ice Sheet are melting at a record rate.

The world’s surface temperature has steadily increased for the past 150 years, and it was assumed the curve would keep climbing at the same rate. But unexpectedly, global surface temperature peaked to its highest historical level in 1998, then flattened out and has remained about the same since, raising questions in the scientific community.

A Lawrence Livermore National Laboratories study that appeared in the Feb. 23, 2014, issue of the journal Nature Geoscience suggests one reason for this unexpected development is the higher than normal rate of volcanic activity over the past 15 years.  Eruptions during that period included 17 ranked VEI 4 on the Volcanic Explosivity Index. A VEI 4 is termed cataclysmic and sends an ash plume 10 to 25km (6 to 15 mi) into the air, sufficient to penetrate the stratosphere with sulfur dioxide aerosols that remain there for months, even years.

“In the last decade the amount of volcanic aerosol in the stratosphere has increased, so more sunlight is being reflected back into space,” said Lawrence Livermore Climate Scientist Benjamin Santer, lead author on the study. “This has created a natural cooling of the planet and has partly offset the increase in surface and atmospheric temperatures due to human influence.” The paper states the research team found evidence for significant correlations between volcanic aerosol observations and satellite-based estimates of lower temperatures, as well as sunlight reflected back into space by the aerosol particles.

Santer’s conclusions seem to be supported by an earlier study by the University of Saskatchewan. In this study, the researchers found that sulfur dioxide aerosols from a very small African eruption had “hitchhiked” their way into the stratosphere. Warm air rising from the seasonal Asian Monsoon lifted the volcano’s aerosols from the lower atmosphere into the stratosphere, where it was detected by the Canadian Space Agency’s satellite OSIRIS, an instrument specifically designed to measure atmospheric aerosols. Even though coming from a small eruption, the concentration of particles was the largest load of SO2 aerosol ever recorded by OSIRIS in its 10 years of operation.

The Lawrence Livermore paper suggests that one other possible contributor to the temporary cooling effect is the unusually long and low minimum in the solar cycle. Don’t be surprised to see surface temperatures start climbing again when volcanic activity subsides and the cooler phase of the solar cycle concludes.

 

 

 

 

 

Why Chile Has So Many Earthquakes & Tsunamis

The Magnitude 8.2 quake that struck off the coast of Chile on April 1, 2014, was the latest in a series of major earthquakes and tsunamis to hit that area in recent years. The undersea quake and resulting 7 ft. (2.1m) tsunami killed 7, toppled buildings, and severely damaged the Chilean fishing fleet.  Earthquake/tsunami events in 2010 (M8.8), 2007 (M7.7), 2005 (M7.8), and 2001 (M8.4) killed more than 1,000 and inflicted billions of dollars in property damage .

The most powerful earthquake ever recorded, a Magnitude 9.5, hit the coast of Chile on May 22, 1960. The monster quake triggered an 82 ft (25m) tsunami that not only battered the west coast of South America, but rolled across the Pacific Basin, devastating Hilo, Hawaii, and damaging coastal villages as far away as Japan and the Philippines. Some sources estimate 6,000 dead and $800 million in property loss (6 billion in 2014 dollars).

Why does this area of planet earth spawn so many high-magnitude earthquakes and punishing tsunamis?

One explanation is that the collision of the two tectonic plates that meet off the South American west coast occurs, in geologic terms, at a very high rate of speed. The oceanic Nazca Plate and the continental South American Plate converge in the Peru-Chile trench that lies about 100 mi (160km) off the coast. The overriding South American Plate moves eastward at 10cm a year, while the subducting Nazca Plate pushes west at 16cm/y, a closing velocity of 26cm/y (about 10 in.), one of the fastest absolute motions of any tectonic plate. The Africa Plate, for example, moves approximately 7 times slower.

This high closing velocity builds up fault line strain much faster than it does when slower-moving plates converge. Every few years, tension on the Peru-Chile fault line builds up to a breaking point. In this latest earthquake on April 1, a 100 mi. (160km) section of the fault line ruptured, allowing the Nazca Plate to ram under the South American Plate. This sudden violent action 12.5 mi (20.1km) below the ocean floor triggered the tsunami and the 8.2 earthquake, and at the same time wedged the South American Plate higher. Uplifting from frequent fault line failures continues to build the Andes Mountain Range into one of the highest in the world. During the 1960 M9.5 quake, some coastal areas uplifted as much as 10 ft. (3m).

As long as the two tectonic plates that meet off the South American coast move geologically at such high speed, major earthquakes and tsunamis will keep happening. We hope the zoning laws and building codes put in place by the governments of Chile and Peru will keep the damage and loss of life to a minimum.  

Why Did the Hill Come Down?

As of this writing, 21 people have been confirmed dead and 30 are missing in the disastrous March 22, 2014, Oso, Washington mudslide. We send our condolences to all those affected by this terrible tragedy. At the same time, we have to ask ourselves why a forest-covered mountainside would suddenly shear off and bury an […]

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Offshore Wind Farms

Constant winds in coastal waters make offshore wind farms highly productive. Most offshore wind turbines are installed on pilings in shallow waters within a few miles of the shoreline, but there are some on floating platforms farther offshore. The United Kingdom’s 20 offshore wind farms supplied 10% of that nation’s total electrical power production in […]

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Sun, Wind, & Fresh Water

Converting ocean water into fresh water is energy intensive, and therefore expensive. Saudi Arabia is a desert kingdom with plenty of oil but very little fresh water. The Saudis burn 1 million barrels of oil a day to produce 60% (4 billion cubic meters) of its total fresh water supply through desalination. If exported onto […]

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Crazy Weather & Global Warming

In the first 6 weeks of 2014, the world spawned some of the most severe weather in hundreds of years, including record snowfall in the Midwest and Great Lakes, record cold in the US northeast, ice storms in the southeast, record drought in the southwest, record flooding and windstorms in the UK, unseasonal warming in […]

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