Download Team Earth Cycle B Ice Sheets B>E>H>A As air temperatures warm

Team Earth
Cycle B Ice Sheets
B>E>H>A
As air temperatures warm, due to global warming, the melting of ice causes a decrease in
sheet ice. If air temperatures continue to rise over Greenland and Antarctica, increased surface
melt will play a large role in ice-sheet mass loss. Increased air temperatures due to carbon
dioxide are warming the Earth’s atmosphere by preventing the release of heat. The heat is
trapped within the Earth’s atmosphere by greenhouse gases creating a blanket around the Earth.
There seems to be study after study showing that global temperature, more specifically the
atmospheric temperature over Greenland, is rising. There is evidence that this rise in temperature
is caused from an increase of carbon dioxide in the atmosphere. These rises in temperature have
shown, and have been predicted to further show, a decline in the amount of Arctic sea ice.
Carbon dioxide has increased from 280 parts per million to 380 parts per million in 2005. Many
scientists believe that higher concentrations of carbon dioxide in the atmosphere will enhance the
greenhouse effect making the planet warmer.
Human activity produces extreme volumes of carbon dioxide and other gasses into the
atmosphere. The gases are trapped in the Earth’s atmosphere, causing an increase in the Earth’s
temperature, which causes an increase in seawater temperature. This is causing the Ice Sheets to
melt. These Ice sheets contain lots of fresh water. With this increase in fresh water in the ocean,
it could affect the currents and circulation of the Earth’s oceans and would change the conveyor
belt heat-distribution system that currently regulates water temperatures. This would lead to the
shutdown of the North Atlantic circulation, which would lead to a drastic cooling of the Earth.
http://www.daviesand.com/Choices/Precautionary_Planning/Arctic_Ice/index.html
http://ecology.com/featuesarchive/earthwarms/index.html
http://www.gsfc.nasa.gov/topstory/20020606greenland.html
http://www.ingentaconnect.com/content/igsoc/jog/2008/00000054/00000184/art00008
http://www.sciencedaily.com/releases/2009/11/091119141039.htm
http://www.cgd.ucar.edu/research/past/interglaciation.html
http://www.eoearth.org/article/Causes_of_climate_change
“National Climate Change” from the U.S. Global Change Research Program
http://downloads.globalchange.gov/usimpacts/pdfs/National.pdf
American Meteorological Society, Glossary of Meteorology
“Greenspace: Greenland ice sheet meltdown: It’s spreading, study finds” from Los
Angeles Times (March 24, 2010)
http://latimesblogs.latimes.com/greenspace/2010/03/global-warming-melting-greenland
E>L>H>B
When alpine and continental glaciers form on the lithosphere, they only occupy a little
more than 2% of the water found on Earth. Even though this is a very small amount compared to
the oceans, which contain 97% of the water found on Earth, the melting of the glaciers would
have a negative impact on the environment. The rise in sea level would not only devastate
coastal cities, but also destroy freshwater systems and habitats.
http://ww
w.uwsp.edu/geo/faculty/ritter/geog101/textbook/hydrosphere/water_distribution.html
Sea level is rising around the world. The Greenland Ice sheet consists of roughly
2,850,000 cubic kilometers of ice. If all of this ice sheet should melt it would raise the sea level
by 7.2 meters. Higher temperatures are expected to further raise sea level by adding the melting
ice sheets, water from mountain glaciers and small ice caps. This raising of the sea level presents
several problems. The first is the contamination of the fresh drinking water and creating a
shortage. Underground water sources in Thailand, Israel, China, Vietnam and some island states
are already experiencing salt water contamination. The second problem is that such a rise would
put almost every major coastal city and a few islands under water. According to IPCC
,Intergovernmental Panel on Climate Change, the expected 3 degrees warming at the end of the
century would, if kept from rising further, result in about 1 meter sea level rise over the next
millennium (see image at the bottom). Even this rise will have an effect on some major coastal
cities. Property owners and federal, state, and local governments are already starting to take
measures to prepare for the consequences of rising sea level. Most coastal states are working
with the U.S. Army Corps of Engineers to place sand onto their beaches to offset shore erosion.
Property owners are elevating existing structures in many low-lying areas, encouraged by lower
flood insurance rates.
Climate Change 2001: The Scientific Basis. Contribution of
Working Group I to the Third Assessment Report of the
Intergovernmental Panel on Climate Change (IPCC) [Houghton, J.T.,Y. Ding, D.J. Griggs, M.
Noguer, P.J. van der Linden, X. Dai, K. Maskell, and C.A. Johnson (eds.)]. Cambridge
University Press, Cambridge, United Kingdom and New York, NY, USA, 881pp. [1],[2], and
[3]..
Modeling results of the sea-level rise under different warming scenarios. The curve labels refer
to the mean annual temperature rise over Greenland by 3000 AD. Note that the temperature
projections shown are greater than globally averaged temperatures (by a factor of 1.2 to 3.1)
http://www.epa.gov/climatechange/effects/coastal/index.html
"Sea Level Rise | Greenpeace International." Google. Web. 22 Oct. 2010.
http://webcache.googleusercontent.com/search?q=cache:cy6LwLVrbeAJ:www.greenpeace.org/i
nternational/campaigns/climate-change/impacts/sea_level_rise/ ice sheet
africa&cd=15&hl=en&ct=clnk&gl=us
http://en.wikipedia.org/wiki/Greenland_ice_sheet#cite_note-IPCC-2001-1
“Hydrosphere.” Universe Today. Web 20 Oct. 2010
"Greenland Ice Sheet Faces 'tipping Point in 10 Years' | Environment | The Guardian." Latest
News, Comment and Reviews from the Guardian | Guardian.co.uk. Web. 22 Oct. 2010.
http://www.guardian.co.uk/environment/2010/aug/10/greenland-ice-sheet-tipping-point
E > L> B >H
Earthquakes are caused when two tectonic plates slip by each other. The two plates have
been pushing against each other which create a tremendous amount of pent up energy that is
released when the plates move. Around 10,000 years ago a series of earthquakes shook
Scandinavia. It is thought that the weight of the ice will suppress the faults. The land is pushed
downward by the weight of the ice making it harder for the faults to slip past each other. When
areas of the lithosphere are covered by massive sheets of ice, the weight of the ice pushes the
crust deeper into the mantle. When the ice melts, weight is removed from the crust, causing
isostatic rebound to begin. The crust returns to its natural position because the mantle below
begins to return to its position, which then pushes on the crust. This occurs due to an increase in
buoyancy and the crust once again floats higher on the mantle. When the ice melts the weight
decreases and the land rebounds upward which could cause more quakes. In ancient times these
quakes affected the areas of south-central Sweden around where Stockholm is located. The water
from the melted ice sheets will not
only cause isostatic rebound, but
will also increase the rise in sea
level.
According to the NASA.gov website, the melting of the Greenland and West Antarctic
Ice Sheets could be a major cause of concern in the future. Satellites have shown a major
thinning of the ice in lower elevations of the Greenland Ice Sheet, adding 0.23 to 0.57 mm/yr to
the sea within the last decade. The complete melting of the ice sheet could cause the seal level to
rise approximately 5 to 7 meters.
http://www.giss.nasa.gov/research/briefs/gornitz_09/
http://www.newworldencyclopedia.org/entry/Glacier
http://www.physicalgeography.net/fundamentals/10h.html
Murphy, B. and Damian, N. (1998) Earth Science Today. “The Ice Age: Sculpting the Modern
Landscape.” Pgs. 426-43
http://news.nationalgeographic.com/news/2008/03/080314-warming-quakes_2.html
E> A > H > L
As the ice sheets melt, the albedo is reduced and the Earth absorbs the energy that is not
reflected. Thus, more heat is retained in the Arctic and Antarctic. Albedo is the amount of
sunlight reflected by an object. The Polar Ice Caps themselves reflect sunlight energy (heat) back
into space, rather than the heat being absorbed by the Earth. When the heat is reflected off of the
polar caps, it is returned to the atmosphere. The melting of the ice sheets creates more open
water. The darker water absorbs more sunlight and heat, rather than reflecting the sunlight and
heat like the lighter, reflective ice does. Another way to explain this refers to albedo. The albedo
of snow-covered ice is about 85%, where the ice-free Arctic Ocean water has an average albedo
of about 40%. As sea ice shrinks, the greater area of darker, ice-free water absorbs more solar
radiation, temperatures rise and more ice melts. I also learned that just as albedo has a negative
feedback affect it also has a positive feedback affect. Ice-albedo feedback (or snow-albedo
feedback) is a positive feedback climate process where a change in the area of snow-covered
land, ice caps, glaciers or sea ice alters the albedo. This change in albedo acts to reinforce the
initial alteration in ice area. Cooling tends to increase ice cover and hence the albedo, reducing
the amount of solar energy absorbed and leading to more cooling according to Wikipedia. So if
you decrease the solar impact in the atmosphere there should be more ice. More ice will raise
sea level affecting the lithosphere.
www.wikipedia.com
http://maps.grida.no/go/graphic/climate-change-iceand-snow-and-the-albedo-effect.
According to studies performed by the scientists affiliated with the International Polar
Foundation, the polar icecaps reflect considerable solar radiation: up to 90% depending on ice
conditions, compared with much lower average albedos for other parts of the Earth's surface.
This keeps the temperature at the poles lower than it would be without the ice cover. Reports
note that Antarctica and Greenland can be considered the northern and southern hemisphere’s air
conditioner. The dramatic sea ice loss over the last number of decades combine with widespread
glacier retreat, has amplified warming in the Polar Regions through the albedo effect, with less
heat being reflected back to space. This amplification in atmospheric warming will likely spread
over the northern land masses, increasing the likelihood of further release of methane trapped in
the frozen permafrost, further fueling global warming.
Based on an article from Global Greenhouse Warming.com, an important property of
snow and ice is its high surface albedo. Because up to 90% of the incident solar radiation is
reflected by snow and ice surfaces, while as low as about 10% is reflected by the open ocean or
forested lands, changes in snow and ice cover are important feedback mechanisms in climate
change. In addition, snow and ice are effective insulators. Seasonally frozen ground is more
extensive than snow cover, and its presence is important for energy and moisture fluxes.
Therefore, frozen surfaces play important roles in energy and climate processes.
A recent paper by Francis & Hunter provides an interesting discussion about reasons for
the recent decline in the Arctic sea-ice extent, based on new satellite observations. One common
proposition about sea ice is that it involves a positive feed-back because the ice affects the
planetary albedo (how the planet reflects the sunlight back to space before the energy enters the
‘climate system’).
http://www.sciencepoles.org/articles/article_detail/climate_change_the_essentials/
http://www.global-greenhouse-warming.com/melting-greenland.html
http://www.realclimate.org/index.php/archives/2006/12/not-just-ice-albedo/
http://www.suite101.com/content/global-environmental-impacts-of-a-warming-arctic-a160748
“Chapter 11:Natural Causes of Climate Change” from Climate Studies: Introduction to
Climate Science (2010) from the American Meteorological Society
“Quick Facts on Ice Sheets” from the National Snow and Ice Data Center
http://nsidc.org/quickfacts/icesheets.html
http://www.carbon-info.org/carboninfo_029.htm
E>H>B>A
As glaciers melt, near the Antarctic Peninsula, an increase in freshwater produces large
algal blooms. These blooms have increased the absorption of carbon dioxide from the
atmosphere. The algal blooms found around Antarctica are one of the few combatants of global
warming. Recent research shows that melting icebergs in the ocean around Antarctica may
actually slow global warming. The iron particles they carry feed algae blooms that suck up CO2.
Professor Peck and his colleagues compared records of coastal glacial retreat with records
of the amount of chlorophyll (green plant pigment essential for photosynthesis) in the ocean.
They found that over the past 50 years, melting ice has opened up at least 24,000 km2 of new
open water (an area similar to the size of Wales) -- and this has been colonized by carbonabsorbing phytoplankton. According to the authors this new bloom is the second largest factor
acting against climate change so far discovered on Earth (the largest is new forest growth on land
in the Arctic).
A geochemist at the University of Leeds, Raiswell had set out with the British
naval icebreaker Endurance in order to investigate a hypothesis long circulated among polar
researchers. The idea holds that icebergs transport tiny iron particles within their frozen mass. As
the gigantic hunks of ice slowly thaw, they release these particles into the Southern Ocean.
There, according to the conjecture, these iron compounds have an incredible effect, bringing the
waters surrounding Antarctica into bloom.
Scientist at Montclair State University are currently coring into the Adelie Drift, in a
small basin on the Antarctic shelf with a water depth of about 1000 m. The basin is filled with
organic sediments composed of more than 90 % diatoms, other microscopic algae and
zooplankton.
NASA researchers found that in polar environments, tiny algae and other plant-like
organisms that are the foundation of the ocean food web grow not just in the open ocean, but also
within brine-filled pores and cracks in the sea ice. In the winter, sea ice insulates the water
below, keeping it above freezing. Algae growing on the bottom of the ice can grow into long
filaments that trail into the water. As the ice melts, and currents and tides jostle and crush the sea
ice into slush and small pieces, the algae are released into the surface water. Blooms of algae and
phytoplankton often occur along the ice edge.
Citations:
http://www.sciencedaily.com/releases/2009/11/091109121117.htm
http://www.spiegel.de/international/world/0,1518,599213,00.html
http://msuinantarctica.blogspot.com/2010/02/seasonal-algal-blooms-recorded-in.html
http://earthobservatory.nasa.gov/IOTD/view.php?id=8517
E>H>L>A
Snow and ice help regulate our planet’s temperature. Snow, ice, and clouds reflect
significant amounts of sunlight keeping us cool. Open water absorbs sunlight and heats the earth.
More open water means more heating and faster melting, which reinforces the cycle. Arctic sea
ice reflects sunlight. The reflection of sunlight helps keep temperatures in the region cool.
Temperatures can be expected to change if there is less ice and longer melt seasons.
(National Snow and Ice Data Center) http://nsidc.org/index.html
http://www.nasa.gov/vision/earth/environment/cryosphere.html
If the earth’s land surface temperature rises over an extended period of time, then melting
of the ice sheets and permafrost will occur more rapidly, therefore, releasing methane gas into
the atmosphere that was capped by the ice sheets and permafrost for many years. According to
Steve Connor, Science Editor of The Independent (see website article,
http://www.independent.co.uk/environment/climate-change/exclusive-the-methane-time-bomb938932.html), “The Independent has been passed details of preliminary findings suggesting that
massive deposits of sub-sea methane are bubbling to the surface as the Arctic region becomes
warmer and its ice retreats.” The article also goes on to state that scientists believe underground
stores of methane are important because scientists believe their sudden release has in the past
been responsible for rapid increases in global temperatures, dramatic changes to the climate, and
even the mass extinction of species. This gas is believed to be 20 times more potent than carbon
dioxide as a greenhouse gas.
http://www.independent.co.uk/environment/climate-change/exclusive-the-methane-time-bomb938932.html
http://en.wikipedia.org/wiki/Arctic_methane_release
http://www.wired.com/wiredscience/2010/03/antarctic-methane-lakes/