Proposal: Sea Level Rise: What's next?

This topic submitted by Nicki and Scott ( barkersp@muohio, nickilyn17@hotmail ) on 2/24/02 .

Climate change and global warming may walk hand in hand and contribute to a fatal future for some of us: the consequence of sea level rise. The burning of fossil fuels increases the amount of greenhouse gases in our atmosphere. These threatening greenhouse gases blanket the earth, trapping in heat and warming earth’s surface. The average temperature of the earth has risen about .5-.7ĄC in the last century, and the last decade of the twentieth century resulted in the warmest temperatures on record for centuries. Sea level rises due to the increased temperatures that are causing thermal expansion of the oceans and the melting of polar ice caps. Currently, the average rate of sea level rise is 2-3 mm/yr, with some places experiencing a higher rate of about 6 mm/yr (Douglas et al, 2001).

About 25% of the sea level rise is due to the thermal expansion of the ocean, and 20% is due to the melting of ice. Warming of the earth’s surface, both land and sea, can also affect atmospheric pressure. If the atmospheric pressure decreases one millibar, the sea level rises 10 millimeters (Sherif 1999). Therefore, the lowering of atmospheric pressure could have a significant impact on water levels in the future. For this project, we will research sea level fluctuations of the past and the predictions for sea level rise in the future. We propose to answer the questions: 1) How much will the sea level rise based on current scientific models? 2) What are some of the consequences of predicted sea level rise? 3) Who will be affected the most?

Understanding sea level rise is interesting and imperative because everyone in the future will most likely be affected in some way. Seventy-five percent of the U.S. population lives within 50 miles of shoreline. Will cities be rebuilt? Manhattan Island will be underwater, Florida coasts will be underwater: where will all these people go? Will we have more problems with overpopulation? How will our freshwater reservoirs be affected? Will agriculture be destroyed? Will storms be more damaging to shorelines? If barrier islands are buried, how will erosion increase on beaches?

Sea level has an enormous impact on ecosystems and habitats in coastal regions. About 100 million people live within one meter of present day mean sea level (Douglas et al). An increase in sea level could erode shorelines at a rate 50-200 times faster than what they are today (Douglas et al). The physical effects of sea level rise are: erosion of bluffs and beaches, increased flooding, saltwater intrusion in coastal aquifers, and storm damage. Not only will beaches shrink, islands alone may be swept away, wiping away generations of culture and traditions. Already there have been disappearances of small islands in Chesapeake Bay (Douglas et al).

Not only is sea level rise a scientific question, but an ethical question. What will happen to future generations of the earth due to our careless ways of burning excessive fossil fuels and polluting the planet? Sea level rise will have the potential to wipe out generations of traditions and cultures, for example the thousands of island nations nestled in the West Pacific.

Based on oxygen isotope dating and geologic evidence scientists have been able to model how sea level has fluctuated in the past. Oxygen isotope records for foraminifera from deep-sea sediments provide significant evidence of the earth’s climate due to orbital changes (Broecker, 1989). The oxygen isotopes studied are d18O and d16O. Colder ocean temperatures and larger ice volume are affiliated with higher signatures of d18O in benthic foraminifera (Broecker, 1989). The drilling of coral reefs has been another means that has provided a continuous and detailed record of sea level (Fairbanks, 1989). Due to global cycling patterns, cooler temperatures have induced extensive glaciation and resulted in a drop in sea level. Approximately 18,000 years ago the sea level is inferred to be 121 meters below what mean sea level is today (Wright, 1993). Interglacial periods of increasing temperature and consequent ice melt have resulted in sea level rise. There is evidence that sea level may have rose up to 20 meters above present mean sea level (MSL) about 125,000 years ago.

We are currently living in an interglacial period and naturally global temperatures should be rising. However, the rate at which the temperature is rising is alarming. Scientists predict sea level to rise faster due to thermal expansion of the oceans and polar ice caps melting due to warmer temperatures. The Intergovernmental Panel of Climate Change (IPCC) predicts that sea level may rise 15-95 cm by the year 2100, with an overall ‘best’ estimate of at least 50 cm by 2100 (Frederick, 1997).
Sea level rise is a consequence of global climate change. Therefore, we also have to consider the reasons why temperatures are rising. Is global climate change a natural phenomenon or are we contributing significantly to greenhouse gases that trap heat on the earth? The biggest question to ask is: Is there a problem and what are we doing about it? Would decreasing carbon dioxide and other greenhouse gases lower the risk of sea level rise? How are we going to protect the innocent island nations of the west pacific if sea level does continually increase? Or what will be in store for the United States?

We will collect resources from the library as well as the internet to have a broad range of materials to draw information from. Currently, there is an abundant amount of research materials available dealing with issues of global climate change. In gathering scientific data, is important to gather as much useful information as possible, so we are looking for the most recent ideas and models of predicted sea level rise as well as articles that have predicted and monitored sea level fluctuations in the past. We have discovered that recent compilations of articles in books dedicated to sea level rise have been fairly knowledgeable. Please go to our folder to view other articles and images we have collected thus far.
During the class discussion we led, we hope we opened people’s eyes to the threat of what sea level rise could possibly damage. The class provided us with positive feedback and we generated a lively class discussion. The students brought up important questions that we are looking into answering. People seemed to be especially interested in what is going to happen to the United States and its coastlines. We hope this enthusiasm continues throughout our project and we appreciate the intuitive thoughts and ideas from our peers.

Resources:
Potential Impact

Out There News

EPA Reports

Global sea level change

CNN Site

Pacific Monitoring

Sea Level Rise Probability

Environmental News Network

Books/Journal References:

Blanchon, P. Deglaciation: The Megaflood-Triggering Hypothesis. Encyclopedia
Of Quaternary Sciences, Chapman and Hall, New York, 1995.

Broecker, W.S. and Denton, G.H. The role of ocean-atmosphere reorganizations in glacial cycles, 1989. Geochimica et Cosmochimica Acta, 53: 2465-2501.

Douglas, B.C., Kearney, M.S., et. al. Sea Level Rise: History and Consequences. Academic Press, New York 2001.

Earth Pulse Climate: Rising Tide of Concern. National Geographic Magazine, Feb. 2001.

Fairbanks, R.G. A 17,000 year glacio-eustatic sea level record: influence of glacial
melting rates on the Younger Dryas event and deep-ocean circulation, 1989.
Nature 342: 637-642.

Frederick, K.D. and Major, D.C. Climate Change and Water Resources, 1997. Climatic
Change 37: 7-23.

Grzechnik, M. and Noye, J. Sea Level Changes and Their Effects. World Scientific,
New Jersey, 2001.

Pinet, P.R. Invitation to Oceanography 2nd Ed. Jones and Bartlett Publishers, Maryland,
1999.

Pirazzoli, P.A., Sea-level Changes:The Last 20,000 Years. Chichester, New York:
1996.

Richman, C. and Titus, J.G. Maps of Lands Vulnerable to Sea Level Rise: Modeled
Elevations Along the U.S. Atlantic and Gulf Coast, 2000. Climate Research:1-34.

Sherif, M.M. and Singh, V.P. Effect of Climate Change on Sea Water Intrusion in
Coastal Aquifers, 1999. Hydrological Processes 13: 1277-1287.

Wright, H.E. et. al. Global Climates since the Last Glacial Maximum. University
Minnesota Press, Minnesota, 1993.

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