Global Warming and A Sudden Rise in Sea Level Focus: Greenland ice sheet By Lisa Hu ‘09.

Global Warming and A Sudden Rise

in Sea Level

Focus: Greenland ice sheet

By Lisa Hu ‘09

Introduction• Climate influences

every aspect of our lives

• The current climate trend shows that annual surface temperatures on Earth are rising

• Greenland ice sheet is melting because of these rising temperatures

Why should we care?

• Global warming is predicted to have an overwhelmingly negative impact on not just human life but the planet’s life.

• Although some positive effects, such as a longer growing season, are predicted, the bad outweighs the good.

• Some of the predicted effects are a rise in sea level, the extinctions of several species, a rapid spread of diseases, and extreme weather patterns, many of which are already occurring.

Evidence of Global Warming

Graphs such as these clearly show the dramatic rise in Earth’s average surface temperature, most of which has occurred in the last decade.

An Interesting Coincidence?

• In addition, a dramatic rise in carbon emissions from the burning of fossil fuels has been noticed on a global scale.

• This helps conclude that the increase in atmospheric CO2 is the fault of humans.

Cause and Effect

• In fact, the increasing CO2 concentration in the atmosphere and the increasing surface temperatures perfectly correlate.

• Therefore, human activities are at fault for global warming.

How does CO2 affect temperature?

A process called the greenhouse effect is responsible for controlling Earth’s climate, and naturally, it does. However, since man has altered the natural process, global warming occurs.

What is the Greenhouse Effect?

• When solar radiation reaches Earth, some is reflected by the atmosphere or clouds.

• Of the radiation that penetrates farther, most is absorbed by the Earth’s surface.

• Earth’s surface then emits infrared radiation back into the atmosphere.

• Greenhouse gases in the atmosphere, like CO2

and water vapor, then trap the infrared radiation and re-radiate it into the lower atmosphere, where it warms the planet.

Melting of Greenland’s Ice Sheet

• The increase of atmospheric CO2 is causing even more infrared radiation to be trapped in the atmosphere, raising temperatures significantly more than usual.

• Higher temperatures are causing the Greenland ice sheet to melt.

• Previously, NASA had estimated that Greenland’s ice sheet would melt a meter every year. Now, it could be as much as a meter every month.

Why is the melting of Greenland’s ice sheet that big a deal?

• There are two types of ice: sea ice and land ice. Sea ice is ice existing in the sea, e.g. icebergs. Land ice is ice existing on land, e.g. Greenland ice sheet.

• Ex: A glass containing ice cubes is filled to the top. When the ice cubes melt, will the glass overflow?

• No. The ice cubes are already in the water, and thus have their mass already in the water. Ice’s lower density and higher volume strike an equilibrium, so that when it melts, it will not change the water level.

• Land ice is not in the water, and therefore, when it melts, it will raise the sea level.

How fast is Greenland melting?

• Previously, NASA had estimated that Greenland’s ice sheet would melt a meter every year. Now, it could be as much as a meter every month.

• In just the past 15 years, over 105 million acres of ice—the equivalent to all the ice in the Alps—has melted and emptied into the oceans.

How much ice is on Greenland?

• Greenland’s ice sheet covers 1.7 million square kilometers (700,000 square miles), and is shrinking by the day.

Current Situation in Greenland

• As one of the fastest moving glaciers, Helheim Glacier loses about half a football field of ice everyday. NASA has confirmed that the large amounts of ice that are calving (breaking off) and melting are a result of the increase in speed of glacial flow.

Projections of Greenland’s Melting

• It was previously thought that the Greenland ice sheet would melt over the course of 1,000 years. Now that time has been dramatically shortened. The red shows the projection of thick ice, while the blue is thin or no ice.

What does this mean for the future? • If the entire sheet were

to melt, the sea level would increase about 7 meters (23 feet).

• Sea level projections show a dramatic rise in sea level in the years to come.

• Sea level rise is also occurring because of thermal expansion. The higher temperatures are causing water to expand, and thus raise sea levels.

How will this impact the environment?

• Major cities like Los Angeles, London, and Tokyo will be flooded as sea level rises.

• Already inhabitants of islands of Vanuatu have had to evacuate due to the rising water and some are already underwater.

• Even today polar bears and other arctic creatures are threatened with extinction due to global warming.

• As time goes on, humans too may become extinct if the climate exceeds our comfort zone.

Bibliography• BBC. “Greenland Ice Is Melting Quicker.” 16 Feb. 2006. BBC News. 11 Jun. 2006. <

http://www.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/4720536.stm> • Chisholm, Suzanne and Michael Parfit. “Greenland Melting? Satellite to Help Find

Answer.” National Geographic Today. 24 Oct. 2002. National Geographic. 2 January 2006. <http://news.nationalgeographic.com/news/2002/10/1024_021024_TVGreenland.html>

• Hadley Center on Climate Research. “Melting Greenland Ice Threatens Global Rise In Sea Level.” 7 April 2004. Hadley Center on Climate Research. 22 December 2005. <http://www.metoffice.com/corporate/pressoffice

/2004/pr20040407a.html>• Jenner, Lynn, ed. “Fastest Glacier in Greenland Doubles Speed.” NASA/Goddard

Space Flight Center. 25 March 2005. • Lovgren, Stefan. “Greenland Melt May Swamp LA, Other Cities, Study Says.” National

Geographic News. 8 April 2004. National Geographic. 2 January 2006. <http://news.nationalgeographic.com/news/2004/04/0408_040408_greenlandicemelt.html>

• Lovgren, Stefan. “Warming to Cause Catastrophic Rise in Sea Level?” National Geographic News. 26 April 2004. National Geographic. 2 January 2006. http://news.nationalgeographic.com/news/2004/04/0420_040420_earthday. Htm

• “Modeling of Long-Term Fossil Fuel Consumption Shows 14.5-degree Hike in Earth’s Temperature.” Lawrence Livermore National Laboratory. 2 November

2005. Public Affairs. 4 January 2006. <http://www.llnl.gov/pao/news/news_releases/2005/NR-05-11-01.html>

Bibliography

• NASA/Goddard Space Flight Center. “Greenland Ice Sheet Flows Faster During Summer Melting.” NASA. 6 June 2002. Top Story. 21 December 2005. <http://www.gsfc.nasa.gov/topstory/20020606greenland.html>

• Oppenheimer, Michael. “Polar Ice Sheets, Melting, and Sea Level Change.” Princeton University. 15 June 2004.

• Pachauri, R. K. “Address to the Ninth Conference of the Parties to the United Nations Framework Convention on Climate Change.” IPCC. 10 December 2003. <http://ww.ipcc.ch/press/sp-10122003.htm>

• Perkins, Sid. “Glacial Change.” Science News. 17 Dec. 2005. ProQuest. 5 January 2006. http://proquest.umi.com/pqdweb?did=954882851&sid=2&Fmt=4&clientId=6785&RQT=309&Vname=PQD

• Ridley, J. K., et al. “Elimination of the Greenland Ice Sheet in a High CO2 Climate.” Journal of Climate. 1 Sep. 2005. ProQuest. 6 January 2006. <http://proquest.umi.com/pqdweb?did=911175141&sid=2&Fmt=3&clientId=6785&RQT=309&Vname=PQD>  

• “Sea Level.” U. S. Environmental Protection Agency. 7 January 2000. Global Warming – Climate. <http://yosemite.epa.gov/oar/globalwarming.nsf/content/ClimateFutureClimateSeaLevel.html>

• http://en.wikipedia.org/wiki/Carbon_dioxide • http://stephenschneider.stanford.edu/Climate/Climate_Science/VariationsSurfaceTe

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