Literature Review on Studies of Rising Ocean Levels
Joe Young
As human-driven climate change continues to progress and impact the natural world, the environmental toll grows more and more apparent. One of many adverse effects associated with the consumption of fossil fuels and the subsequent increase in global temperatures is the rise of sea levels across the globe. Unlike many aspects of climate change, rising ocean levels have the ability to directly impact human life, in the near future. As the average global temperatures rise, polar ice melts and releases previously frozen freshwater into the oceans. Over time, the amount of freshwater dumped into the seas becomes sufficiently great to measure a change in the ocean level on Earth’s coasts. In addition to the influx of freshwater, increased sea levels also come as the result of thermal expansion. Water volume increases as temperature increases. When the global temperatures increase, so too does the temperature of the oceans. These two factors lead to a devastating rise in sea levels, which will greatly impact humans and wildlife alike.
Current scientific projections predict a rise in water levels of about one meter by the year 2100 and another meter every hundred years after, if the current trends continue (1). This is a change that will directly affect millions of humans and millions more indirectly. Increased ocean levels lead to greater storm frequency (6), inundations, loss of coastal land (1), increase in vector borne diseases (4), and contribute to drastic changes in climate (3). In the United States alone, there are 180 coastal cities that could lose 9% of their total land area with a sea level rise of one meter (1). Atlantic cities will most likely be the hardest hit. Tampa, Miami and New Orleans could all face a 10% loss of land, as coasts recede. The humanitarian and economic impact of this rise will be enormous. Most likely, special works projects will need to be constructed in order to combat major flooding across the city centers, at great economic cost to federal and regional governments. In addition to increases in temporary flooding, these cities will experience large-scale permanent inundations, losing land to the sea indefinitely (1). Long-term projections also show grim predictions for densely populated cities like New York City and Boston, which could both lose 10% landmass in the coming centuries (1). There are approximately 40.5 million citizens living in coastal regions of the United States according to the 2000 census. Land losses across coastal cities will affect millions of Americans, who will experience flooding and depending on their location, will have to relocate farther inland. This issue is worse on a global scale. The United States is fortunate in its lack of extremely low-lying regions. Other nations however, are not so fortunate.
Rising ocean levels could create 50 million environmental refugees worldwide by the year 2050 (5). There has never been a historical precedent of this many dislocated individuals. Currently there are about one-fourth that amount of refugees from the various international conflicts. An influx of 50 million new refugees over the next 35 years would create separate political crises and strain, as neighboring and foreign countries attempt to accommodate and help those who were forced to move. Regions in Southern Asia will produce the greatest amount of dislocated individuals, including Bangladesh, which is most vulnerable to coastal flooding and could produce an estimated 17.5 million refugees alone (5). The individuals displaced primarily reside in developing countries and do not have the means to easily relocate. The irony of the situation is that the people in the most affected nations contribute very little to the climate change that will force them into this situation. The result of all these factors is a humanitarian crisis unlike any that has come before it, due to a largely avoidable process.
The humanitarian impact of rising sea levels will also go beyond flooding and land erosion. Within this century, these trends could threaten global climate patterns, by disrupting the North Atlantic Current. The University of Potsdam in Berlin published a study, which explores the large-scale impacts of the potential breakdown of the NAC. Its results are far from definitive. Their best estimates claimed a 50% chance of a total breakdown of the NAC (3). While this study does not provide conclusive evidence as to whether or not the NAC will survive rising ocean levels, it does offer insight into the potential effects it could have on European climate. The North Atlantic Current is one of the most powerful ocean currents, and continues the Gulf Stream to the north east of the Atlantic Ocean. It is partially responsible for the temperate climate of Europe and Scandinavia. The Potsdam study determined that without the warm current, the climates of those regions could grow cooler as the moderating effects of the NAC deteriorate. However, these results are contradicted by The United Nations Intergovernmental Panel on Climate Change, which claims that it is very unlikely for the NAC to disappear before 2100 (8). The panel further explains that the NAC is only one factor that moderates Europe’s climate, and a full deterioration of the NAC would not have a drastic impact on the European climate. Between these two sources, the United Nations panel is the more credible and reliable, given its resources and official status. The Potsdam study’s results do not seem to accurately reflect the general scientific consensus on the issue of the deteriorating NAC. Regardless of the timeline, or to what extent humans will feel the impact, rising ocean levels at the current rate will have an impact on the European climate as a direct result of human activity.
There are numerous ecological impacts that stem from a rise in sea levels. A study published in 2011 explored the potential increase in vector borne diseases due to rising ocean levels. Many vector species require brackish or slightly saline waters to lay eggs and reproduce. As the ocean levels rise, freshwater ponds, lakes, mangroves and swamps in coastal areas will be contaminated with salt water, which will wreak havoc on the freshwater ecosystems, while simultaneously providing brand new habitats for disease ferrying insects. To test this hypothesis, the conductors of the study observed rates of vector borne diseases following the 2004 tsunami in South East Asia. As the Tsunami waters salinized fresh bodies of water inland, there was a spike in the number of cases of vector borne diseases, which supports the author’s claim. However, it is difficult to definitively determine whether this increase would also exist in other parts of the globe, as coastal flooding increases elsewhere. Because the sample study was only a one-time event and in one location, the data collected is relatively localized. Since changes in ocean levels occurs over centuries, the timeline of rising ocean levels is too long to conduct a formal experiment with the actual conditions of the hypothesis. This study provides substantial evidence that an increase in vector borne diseases could occur in certain regions of the globe, but does not sufficiently substantiate the claim that this will be a worldwide trend.
The main threat to wildlife from the rising ocean levels is habitat destruction. The next century will bring about a substantial loss of both terrestrial and marine habitats. The National Wildlife Federation recently conducted a study examining the future effects of rising tides in the Chesapeake Bay and the Puget Sound (2). Its study in the Puget Sound analyzed the impacts of a range of ocean level rise predictions, from the moderate to the more severe. For their study, the NWF focused on the consequences associated with a two-foot rise by the year 2100, specifically the impacts on salmon populations. The study explains that salmon instinctively return to their birth locations each year to lay eggs and reproduce. As ocean levels rise, these reproductive habitats will change and confuse the salmon populations who will not be able to locate their original breeding grounds. The study found that this alone will cause a dramatic drop in salmon population, which could then trigger a chain reaction up the marine food web. Salmon are a staple of an Orca’s diet. As the salmon suffer, so too do the Orcas, who are already on the endangered species list. This study exemplifies the rippling effects that the rising oceans can have on marine ecosystems. A small disruption in the marine food web can grow exponentially as it affects all of the other organisms that rely on each other in marine ecosystems.
One of the more commonly discussed impacts of rising sea levels is the fate of coral reefs around the globe. The Australian government conducted a study examining the potential repercussions on the Great Barrier Reef over the next century, as the ocean continues to rise. The study found that coral reefs are fairly resilient against changes in sea levels, since they can grow about 6mm towards shallower waters each year, to compensate for the deepening waters (7). However, if the water levels begin to rise faster than coral reefs can grow, as some studies predict, then the health of the coral reef ecosystems will be greatly jeopardized. The Great Barrier Reef grows at a very calculated distance below the ocean surface. The distance from the surface to the reef is just enough for the reef to receive no more and no less sunlight than it needs. If that distance is interrupted, it disrupts the photosynthetic processes of the reef. The study involved measuring the amount of sunlight that penetrates certain depths of water, and determining how deep coral could survive based on the amount of sunlight it requires. Given that the Australian Government conducted this study, it focuses on the Great Barrier Reef, and the properties of the oceans around the Great Barrier Reef. Therefore its results are specific to Australia. The general conclusions can be applied to other reefs around the globe but the specific data collected are not universal. The study’s results found that with current predictions for ocean level rise the reef will begin to suffer losses due to decreases sunlight around the year 2050. At that year, the rate of ocean level rise will begin to outpace the coral’s rate of growth, consequentially the coral will reside deeper and deeper below the surface will be unable to reach the sunlight it needs.
The consequences of increased ocean levels are extensive and diverse. The issues associated with this process will directly affect millions of humans making it one of the direst outcomes of global warming. If not for our own sake, we need to reverse the rising tides to protect the endangered wildlife at risk. The perpetuating factor of rising sea levels, and global warming in general is simply the lifestyle of billions of humans. To change the impacts on the oceans, we as humans have to change the ways we live. So often we ignore the warnings of global warming and continue our consumption of energy and fuels, which continues the deterioration of the Earth. If we continue our ways and refuse to change, we will soon feel the effects of global warming on a first hand basis
WORKS CITED
- “Rising sea levels.” The Science Teacher 78.4 (2011): 17. Academic OneFile. Web. 14 Sept. 2014.
- “Examining The Impact Of Rising Sea Levels.” National Wildlife (World Edition) 46.1 (2007): 52. Points of View Reference Center. Web. 10 Sept. 2014.
- Julio Godoy* – IPS/IFEJ. “ENVIRONMENT: Oceans Warming and Rising.” IPS –Inter Press ServiceDec 21 2006. ProQuest. Web. 10 Sep. 2014 .
- Ramasamy, Ranjan. “Possible Impact of Rising Sea Levels on Vector-borne Infectious Diseases.” Biomed Central (2011): n. pag. BMC Infectious Diseases. 18 Jan. 2011. Web.09 Sept. 2014.
- “Rising ocean levels will create millions of refugees.” Globe & Mail [Toronto, Canada] 22 Aug. 1989: A10. Infotrac Newsstand. Web. 9 Sept. 2014.
- Shankar, Vedantam. “Glacier Melt Could Signal Faster Rise in Ocean Levels. “Washington Post, The n.d.: Newspaper Source Plus. Web. 9 Sept. 2014.
- “Working Together Today for a Healthier Reef Tomorrow…” Impacts of Sea Level Rise on the Reef. Great Barrier Reef Marine Park Authority, n.d. Web. 21 Sept. 2014.
- “Climate Change Synthesis Report.” (2007): n. pag. Intergovernmental Panel on Climate Change. United Nations, 2007. Web. 21 Sept. 2014.