Volcanoes and Climate Change
By Anneka Kielman
Section AG
What happens when a volcano erupts?
Image from Solcomhouse.
Hampton University, Center for
Atmospheric Sciences
• They release large clouds into the air which contain ash and sulfuric
gases (that turn into aerosols).
• Aerosols reflect solar energy output from the sun, keeping the sun
from warming the Earth, creating a cooling effect.
• “Volcanic eruptions…can impact global climate, reducing the amount
of solar radiation reaching the Earth's surface, lowering temperatures
in the troposphere, and changing atmospheric circulation patterns”
(Jason Wolf, NASA Earth Observatory).
Notes
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The large amount of gas and ash released can affect climate patterns for years.
Sulfuric gases change into sulfate aerosols, which can stay in stratosphere for up to four
years . The aerosols reflect solar energy output from the sun, keeping the sun from warming
the Earth.
“Major eruptions alter the Earth's radiative balance because volcanic aerosol clouds absorb
terrestrial radiation, and scatter a significant amount of the incoming solar radiation, an
effect known as "radiative forcing" that can last from two to three years following a volcanic
eruption.” (Jason Wolf, NASA Earth Observatory. September 5, 2000.
http://earthobservatory.nasa.gov/Features/Volcano/)
When large amounts of gases from volcano eruptions get to the stratosphere, they can
produce an extensive cooling effect.
Warming in the Stratosphere, warming in troposphere in winter, cooling in troposphere.
Image 1: Solcomhouse. www.solcomhouse.com/volcano.htm
Image 2: http://cas.hamptonu.edu/centerinfo/photo-album/ScienceGraphics/volcano.html
via Google.com
Image on title slide: www.brixworth.demon.co.uk/geography/year7.htm via Google.com
Mount Pinatubo erupted in 1991 putting 20 million tons of sulfur dioxide and ash into the
atmosphere.
Human made emissions can enhance/increase the effects on the global climate system
www.Global-greenhouse-warming.com
Up left and down right images from
Solcomhouse
Volcanoes around the world
Smithsonian Institution, Global Volcanism Program. (Solcomhouse)
Notes for visual slides 2 and 3
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Image 1: www.solcomhouse.com/volcano.htm via Google.com
Image 2: www.global-greenhouse-warming.com via Google.com
Image 3: www.solcomhouse.com/volcano.htm via Google.com
Volcano erupts, clouds shoot high in the air, winds blow particles.
Ash falls (can fall far away from source of eruption due to wind).
Sulfur in the eruptions results in acid rain.
After volcanic eruptions, aerosols in the atmosphere cause sunsets to look
different.
In 1915 the Tambora Volcano erupted in Indonesia causing many changes in
climate in the year 1916. It was called “the year without a summer” due to the
frosts in the summer all over the country (NASA Facts Online
http://www.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci/volcano.htm)
NASA has satellites that monitor changes in the atmosphere and measure the
effects of volcanic eruptions in the atmosphere.
Local Volcanic Eruption: Mt. St Helens
Seattle Times News Source
Physical Geography.net
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Mt. St Helens erupted on May 18, 1980.
The ash cloud grew 12 miles into the air.
The volcanic ash from the eruption spread heavily over 11 states, as far as Oklahoma, and
some traveled around the globe in 2 weeks.
“During the nine hours of vigorous eruptive activity, about 540 million tons of ash fell over an
area of more than 22,000 square miles (60,000 km²).[3] The total volume of the ash before its
compaction by rainfall was about 0.3 cubic miles (1.3 km³).[3] The volume of the
uncompacted ash is equivalent to about 0.05 mile³ (208,000,000 m³) of solid rock, or about
7% of the amount of material that slid off in the debris avalanche.[3] By around 5:30 p.m. on
May 18, the vertical ash column declined in stature, but less severe outbursts continued
through the next several days” (Wikipedia:
http://en.wikipedia.org/wiki/1980_eruption_of_Mount_St._Helens ).
In all, Mt. St. Helens released 24 megatons of thermal energy, 7 of which as a direct result of
the blast. This is equivalent to 1,600 times the size of the atomic bomb dropped on
Hiroshima. [23]
Image 1: Mark Nowlin. May 18, 2004. seattletimes.nwsource.com/.../eruption.html via
Google.com
Image 2: http://www.physicalgeography.net/fundamentals/7y.html via Google.com