Global Warming and its Affect on Ocean Stability

A Case Study on the Possible Results of Continued Global Warming.

By Lucaya Luckey-Bethany.

Based on the interview with Dr. Albert Hine.

 

This case study is also available in the following formats:

Adobe PDF • Open Document • Word Document

Contents:

Abstract • The Broad Picture • Indications of a Growing Problem • Questions and Scenarios • References

Abstract

Increased pollution levels have in turn escalated the amount of greenhouse gases present in Earth’s atmosphere thus trapping in excess solar energy.  This phenomenon is commonly referred to as global warming or the Greenhouse Effect and it may be responsible for the high amount of glacial runoff coming from the polar ice caps.  This may affect global climate and ocean levels.  This case study will illustrate the potentials risks involved with continued pollution practices and some possible results of non-action.

The Broad Picture

Greenhouse gases occur naturally in Earth’s atmosphere; these are defined as any gas that absorbs infra-red radiation from the sun.  Pollutants also contain these same gases, (namely carbon dioxide, methane, and nitrous oxide), which are introduced into the atmosphere.  As solar radiation passes through the cloud cover, Earth absorbs the radiation it needs and the rest is reflected back up into space, (the most powerful reflecting mechanism are the oceans), yet the increased levels of greenhouse gases trap the extra radiation and keep it from exiting Earth’s atmosphere, creating a veritable hothouse.

The affects from a warmer planet can have either good or bad connotations, farmers can produce crops farther north and the growing season is far longer.  Also, several staple plants use carbon dioxide as a mechanism for continued growth, expelling oxygen as a waste product.  Others; however, do not respond so well to such drastically increased amounts of carbon dioxide present in the atmosphere.   Another possibility to consider is that heat waves, droughts, and floods may last longer and be more severe, as well as the fact that pathogens within the air and soil, as well as insects thrive in moist, warm conditions, thus a greenhouse effect would be an ideal breeding ground for disastrous pests or blight.

More so than just potentials for what may occur on land, one must also take into consideration the sea—for this is where some truly devastating changes can occur.  One of the most fundamental engines which drive the ocean currents is the thermohaline layer which exists in the deep oceans.  The principles of density explain how these waters circulate and renew not only the ocean’s oxygen supply but also is an important provider of heat.  Saltier and colder water is denser than warmer or less salty water because the warmer the liquid is, the less compact the molecules are, and less salty water means that there is less weight by volume—thus when glacial melt from the polar ice caps mixes with the warmer ocean water it automatically sinks to the bottom.  This cold layer of water slowly makes its way to the equator, where it warms up and rises to the surface, only to make its journey back to the poles to replace the water which had sunk to the ocean floor.   These new supplies of water carry fresh oxygen and also carry the heat from the equator back up into the Polar Regions, the Gulf Stream alone transports 27,000 times the amount of heat than all of Britain’s power supplies could master.   If these polar ice caps were to melt very rapidly, (geologically speaking), the global levels of ocean salinity and density would be affected dramatically, thus interrupting the flow of the ocean currents up to the northern-most regions of the earth, as oceanographer Wallace Broecker said, “[deep-water formation is] the Achilles heel of the climate system”.

Also, the increased amount of water added to the world’s oceans could raise the water level all around the globe.  Granted that this shift would be a very slow and miniscule change, it could have some very dramatic consequences.  With every foot of sea-rise to occur, the beaches may lose anywhere from fifty to one hundred feet of land –between 1960 and 1990 the population of the United States’ coastal areas rose by 41% and by 1990 54% of all Americans lived in a coastal region, in effect, less than one fifth of the United States’ land mass accounts for one half of all the nation’s housing and population.  
Increased flooding could result from the top-heavy oceans which would also multiply the affects of coastal erosion, thus destroying protected habitats such as the wetlands, which serve as a home for many endangered species.  Also, large levels of salt water flooding destroys local water supplies and would destroy local tourism.  The shallow ocean waters would heat up and the coastal fish would chase the cooler water in to deeper waters away from commercial fishermen.   The Coastal states comprise 3/4ths of the economic structure of the United States in totality,  a rapid decline in the amount and quality of available land, coupled with the loss of commercial fisheries could spell economic disaster for the U.S., not to mention the dozens of third-world countries which also depend on the world oceans for survival.  Some people are striving to enact change, Senator Susan Collins introduced the Abrupt Climate Change Act of 2003 , yet not enough attention is being paid to those who have the necessary information and as thus, the Act has not been given much credence in the face of more pressing national problems.

Indications for a Growing Problem

Existing floating ice, if melted, would not drastically raise the level of the world’s oceans because the displacement of the ice would roughly equal what would be added to the surrounding water if the ice were melted.  Yet this could affect the thermohaline layer and the longitudinal currents which bring much-needed warmth to coastal nations.  However, if the land-based ice of Antarctica were to melt suddenly, the results would be quite different.  As of 1995 studies found that the West Antarctic ice shelf, (which was once 1/3rd of the continent), had become less than 10% of the size of the East Antarctic ice shelf and predictions estimate that if the rest of the west shelf were to melt, the oceans could raise up to six meters.  If the east shelf melts, possibilities are that global oceans could raise 60 meters; this is a cause-and-effect relationship because the west shelf is currently holding the east from pouring into the sea.   If estimates are correct and 50-100 feet of land could be lost for every foot of ocean gained, the fact remains that a great amount of available land would eventually be hundreds if not thousands of feet below the surface. 

Professor Anders E. Carlson of Oregon State University discovered that the Laurentide Ice Sheet has lost around 9% of its total mass, a shift which occurred immediately after a period of South Atlantic warming,  and the British Antarctic Survey found that not only has 13,000 sq. kilometers of ice in the Antarctic Peninsula been lost over the past 50 years, but also that the Larson A Ice Shelf (1,600 sq km) broke off in 1995, the Wilkins Ice Shelf (1,100 sq km) broke off in 1998, and the Larson B Ice Shelf (13,500 sq km) broke in 2002.  The floating ice is disappearing and the continental ice has begun to be affected, for the Polar Regions are melting at a rate 2 to 3 times faster than the global average.   The poles act as a sort of barometer which would indicate the beginning of a possible climate change, and these red flags have begun.  The Odden Ice Shelf in the Greenland Sea used to form annually and act as a “superconductor” for the Gulf Stream.  In 1997 the shelf stopped forming because it was no longer cold enough in Greenland for the massive amounts of ice to remain throughout the winter, and the remaining glacier has become 46% thinner over the past 20 years.  As a result, one of the most influential drivers of the Gulf Stream has stopped working.  Twelve columns of super-cooled water were once constantly in motion under the floating ice pack, yet now only two can be found, and neither one is strong enough to reach the seafloor. 

If this continues, widespread disruption of the Gulf Stream may be a result.   This is something to be concerned about, since warming in the 20th century is greater than at any other time in the past 400-600 years, and the global seal level has been rising about three times faster in the past 100 years than in the previous 3,000 years of geological history.   Yet, one must remember that the time scale in question accounts for centuries.  This may be the geological blink of the proverbial eye, but in a human scale it is a miniscule change that will not result in any easily foreseeable consequences, but the shift is beginning, and a global climate shift is entirely possible if no action is taken to stop or reverse the growing trend.

Questions and Scenarios:

Provide short, but concise answers to the following questions.

References

New 5/6/11 – Global Warming: What To Know About Today’s Hottest Topic

1. http://www.epa.gov/climatechange/
2. http://www.gcrio.org/CONSEQUENCES/summer95/agriculture.html
3. http://www.climatehotmap.org/global-warming-effects/
4. http://www.answers.com/topic/thermohaline-circulation
5. London Times, published May 8, 2005
6. http://www.climatehotmap.org/global-warming-effects/
7. http://ccma.nos.noaa.gov/publications/eutroupdate/
8. Andrews, Kacky.  Florida Department of Environmental Protection, Informational Briefing and Lecture given on October 11, 2004. University of South Florida
9. http://www.climate.org/publications/climate-alert.html
10. London Times, published May 8, 2005