Iceland Eruption Expected to Lead to Short-term Cooling
Volcano could mean cooling, acid rain
'Not like Pinatubo' so far, but
potential is there
msnbc.com
staff and news service reports, April 15, 2010
If Iceland's
active volcano gets even more active, Icelanders and air travelers won't
be the only ones impacted. Gases from past large volcanoes have
actually lowered Earth's temperatures, triggered lung ailments, caused
acid rain and thinned our protective ozone layer.
The
Eyjafjallajokull volcano isn't there yet. "This is not like Pinatubo. So
far the scale is not big enough to have a global effect," Hans Olav
Hygen, a climate researcher at the Norwegian Meteorological Institute,
said in reference to the 1991 eruption in the Philippines.
But the potential
is there. The new eruption is 10 times more powerful than another
nearby last month, threw up a cloud of ash nearly seven miles high and
closed down air traffic across northern Europe.
The most
dangerous gases released during an eruption are sulfur dioxide, carbon
dioxide and hydrogen fluoride.
High levels of
ash particles can cause increased coughing and irritate the eyes and
skin and sometimes result in serious lung conditions.
When the acid
coating on ash is removed by rain, it can pollute local water supplies
and damage vegetation. On the other hand, ash deposits can be beneficial
by improving the fertility of soil.
Already in
Iceland, residents and visitors are being urged to stay indoors due to
the ash fall and to wear dust masks if they must venture outside.
Moreover, farmers are worried that their livestock will eat and digest
ash, causing a die-off like the one in 1918 when another Icelandic
volcano erupted.
Three previous
eruptions of Eyjafjallajokull are known in the 1,100 years of Iceland's
recorded history. The most recent began in December 1821 and lasted for
more than a year, then a neighboring volcano erupted in 1823. Other
eruptions include one around 1612 and 920.
Longer term,
sulfur from volcanoes has the potential to cool the Earth. Sulfur reacts
with water in the air to form sulfuric acid droplets that reflect
sunlight hitting Earth, thus blocking some rays. The reduction in
sunlight can reduce temperatures for a year or so, until the droplets
fall out of the atmosphere.
Indeed, Pinatubo
is known to have cooled the planet by 0.9 degrees Fahrenheit.
Some experts
advocate the deliberate injection of sulfur dioxide in the stratosphere
in a "geoengineering" short cut to slow global warming.
That option has
become attractive for some after a U.N. climate summit in Copenhagen in
December failed to produce a binding global deal to cut emissions of
greenhouse gases. Others say the risks are too big — ranging from
disruptions of weather patterns to acid rain.
Other examples of
how the environmental impacts of volcanoes can go far beyond their
immediate area:
* In 1783, a
poison cloud from the eruption of Iceland's Laki volcano killed
thousands of people across Europe and undermined farm output by spewing
an estimated 120 million tons of sulfur dioxide into the air, said Colin
Macpherson, a geologist at the University of Durham in England. That
amount of sulfur dioxide was three times European industrial output in
2006.
* In 1815, the
Tambora volcano eruption in Indonesia killed an estimated 92,000 people,
and its ashes swept all the way to Europe, blanketing the continent and
turning 1816 into a "year without summer."
* In 1883,
Krakatoa erupted in Indonesia killing 36,000 and created vivid red
twilights in Europe from November 1883 through February 1884 — a fact
reflected by painters of the period.
* The 1980 Mount
St. Helens volcano eruption in Washington state, in which 57 people
died, created a cloud of ash 2,500 miles long and 1,000 miles wide.
|
