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January 06 2012

14:45

Rethinking the Effects of Aerosols

A study projects that the elimination of direct atmospheric aerosols over the eastern United States would increase ground temperatures.

April 20 2011

14:43

Earthquakes, Tsunamis, Volcanoes, Oh My!


Scientists predict increased global warming can lead to more earthquakes and other "natural" disastersJust when we thought that things couldn’t get any worse after last year, with its record breaking heat waves, snowstorms, floods, drought, fires and extreme weather events including the volcano in Iceland and a tornado in New York City, then this year began. Already, in only the first 3 months, we have seen flocks of dead birds falling from the sky, schools of dead fish floating in marinas, deadly mudslide in Brazil, floods in Australia the size of Germany and France, and a massive earthquake and tsunami in Japan…

Now all of these events, last year and this one may seem unnatural, unexpected, bizarre, and yet all have been predicted by climate models as a result of climate change. Yes, if you were wondering about the reality of climate change, it is here. And this is only the beginning.

Geologists predict that with further global warming, we will see even more earthquakes, tsunamis and volcanoes, and in seemingly unexpected places like the Arctic and Newfoundland.

This is because glaciers, with their enormous weight (ice weighs about one ton per cubic meter), exert a great amount of pressure upon the surface of the Earth that they cover. As they continue to melt at an ever-increasing rate, this pressure on the underlying earth is released, resulting in a myriad of geologic reactions – earthquakes, tsunamis and volcanoes.

“What happens is the weight of this thick ice puts a lot of stress on the earth,” Prof. Patrick Wu, geologist at the University of Alberta, explains. “The weight sort of suppresses the earthquakes, but when you melt the ice the earthquakes get triggered.”

Some also suspect that as the ice melts, which causes sea levels to rise, more weight is added upon the ocean floor, and subsequently upon the tectonic plates below.

“All over the world evidence is stacking up that changes in global climate can and do affect the frequencies of earthquakes, volcanic eruptions and catastrophic sea-floor landslides,” says British geologist Bill McGuire.

Sources and further reading:
Fire and Ice: Melting Glaciers Trigger Earthquakes, Tsunamis and Volcanoes
Melting glaciers could have fiery result, geologists warn

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March 23 2011

21:45

October 28 2010

12:32

June 24 2010

22:24

EarthTalk: Volcanoes and Global Warming


The amount of greenhouse gases emitted by even a large and ongoing volcanic eruption is miniscule compared to industrial and automotive carbon emissions caused by human activity. Global warming can, however, help trigger volcanic eruptions by melting the ice that keeps rock from turning to magma. Pictured: The Arenal Volcano in Costa Rica, one of the 10 most active volcanoes in the worldEarthTalk® is a weekly environmental column made available to our readers from the editors of E/The Environmental Magazine

Dear EarthTalk: Is there any link between increased volcanic activity—such as the recent eruptions in Iceland, Alaska and elsewhere—and global warming? – Ellen McAndrew, via e-mail

It’s impossible to pin isolated natural phenomena—like an individual volcanic eruption—on global warming, but some researchers insist that there is a correlation between the two in some instances.

“Global warming melts ice and this can influence magmatic systems,” reports Freysteinn Sigmundsson of the Nordic Volcanological Centre at the University of Iceland. Her research with Carolina Pagli of the University of Leeds in England suggests that rocks cannot expand to turn into magma—the primary “feedstock” for volcanic eruptions—when they are under the pressure of a big ice cap pushing down on them. As the theory goes, melting ice caps relieve that pressure and allow the rocks to become magma. This in turn increases the chances of larger and/or more frequent eruptions in affected regions, from Iceland to Alaska to Patagonia to Antarctica.

As for Iceland specifically, the eruption of Mt. Ejyafjallajökull that shut down some air travel for weeks this past spring cannot be blamed on changing climate: That volcano lies under a relatively small icecap which would not exert enough pressure to affect the creation of magma. But Sigmundsson and Pagli found that the melting of about a tenth of Iceland’s biggest icecap, Vatnajokull, over the last century caused the land to rise an inch or so per year and led to the growth of an underground mass of magma measuring a third of a cubic mile. Similar processes, they say, led to a surge in volcanic eruptions in Iceland at the end of the last ice age, and similarly increased volcanic activity is expected to occur there in the future.

On the flip side, volcanic eruptions can exacerbate the ongoing effects of climate change: Already retreating glaciers can lose all their ice when something below them blows. Of course, many volcanoes around the world are not subject to pressure from ice caps, and scientists stress that there is little if any evidence linking global warming to eruptions in such situations.

Some have theorized that large volcanic eruptions contribute to global warming by spewing large amounts of carbon dioxide and other greenhouse gases into the stratosphere. But the amount of greenhouse gases emitted by even a large and ongoing volcanic eruption is but a drop in the bucket in comparison to our annual output of industrial and automotive carbon emissions.

According to the U.S. Geological Survey, greenhouse gas emissions from volcanoes make up less than one percent of those generated by human endeavors. Also, ash clouds and sulfur dioxide released from volcanoes shield some sunlight from reaching the Earth and as such can have a cooling effect on the planet. The 1991 eruption of Mt. Pinatubo in the Philippines—a much larger eruption than what occurred recently in Iceland—caused an average cooling of half a degree centigrade worldwide during the following year. Regardless, single volcanic eruptions, even if they last for weeks or months, are unlikely to send enough gas or ash up into the skies to have any long term effect on the planet’s climate.

Contacts:
Nordic Volcanological Centre
U.S. Geological Survey

Additional reading:
Iceland Volcano and Its Effect on the Environment

Image credit: Frank Kehren, courtesy Flickr
—————-

SEND YOUR ENVIRONMENTAL QUESTIONS TO: EarthTalk®, c/o E – The Environmental Magazine, P.O. Box 5098, Westport, CT 06881; earthtalk@emagazine.com. E is a nonprofit publication. Subscribe: www.emagazine.com/subscribe; Request a Free Trial Issue: www.emagazine.com/trial

April 19 2010

08:28

Eyjafjallajoekull and all that

There are two types of natural disaster - the ones that we can cause like landslides from deforestation, sea level rises from climate change, or deadly smogs from air pollution, and the big geological disasters like volcanos and earthquakes that we have no control over. The former we have to mitigate their likelihood and adapt to their impacts, the latter we can only adapt to.

The newspapers here in the UK are dominated by the unpronounceable Eyjafjallajoekull volcano and its plume of ash which has grounded flights across northern Europe - much more coverage than the devastating earthquakes in Haiti, Chile and China, it should be noted. A detail that has passed many by is that while we do have a network of nine Volcanic Ash Advisory Centres around the world, we seem completely unprepared for how to deal with closed skies. Fruit and veg is rotting in airports rather than being freighted to Europe, manufacturers with Just In Time supply chains are tearing their hair out, and about a million Brits are stranded abroad.

Nature is famously resilient to short term shocks. Trees will survive explosions which demolish houses, by bending instead of resisting. We have the technology to build earthquake proof houses, yet continue to build rigid homes on earthquake zones around the world (often demolishing more resilient traditional constructions in the the name of progress). The only resilience we have seen in the face of the volcano has been a surge in video conferencing.

There is a story (possibly apocryphal) that the internet was designed to be resilient to nuclear strikes in the US, by automatically routing data through surviving paths. I think we need to design all our systems along similar lines rather than relying on a single route or a single style of housing working everywhere. And we need to get our adaptation to climate change started very soon.

Resilience. It's the future.

April 18 2010

23:11

Volcanic ash cloud: Global warming may trigger more volcanoes

Climate change could spark more ''hazardous'' geological events such as volcanoes, earthquakes and landslides, scientists have warned.

April 16 2010

18:50

Greens shouldn't blow their top over Eyjafjallajökull

The volcanic disruption may distract from combating climate change, writes Geoffrey Lean.
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