The societal costs of rising sea levels

In the debate surrounding rising sea levels, few arguments stem from the ecological scientists and economists working to study it. In an effort to bring their expertise and insights into the discussion this paper compiles the support for rising sea levels, its potential costs, and how society can internalize these costs. Economics provides a good foundation from which to approach the topic of rising sea levels, but some ideas such as the concept of the “long run” maximization of profits for a firm need alteration. Since scientists can increasingly accurately measure the rate of ice melt and subsequent consequences on the global economy, an economically efficient solution could be a permit abatement system by which a firm’s carbon dioxide emissions are limited. This suggests that firms can trade their permits to maximize efficiency and limit the continued pollution, which causes sea level rise.

Before exploring the economic impact of sea level rise, we must first consider the different costs associated with it. Biologist David Archer suggests two reasons for the rise in sea level: “First, the water in the oceans expands as it gets warmer; this is called ‘thermal expansion.’…Second, additional water enters the ocean from the melting of ice on land” (Archer 94-94). As Archer posits, the heating of the planet through emissions of carbon dioxide and other greenhouse gases causes the ocean to absorb more heat, expanding and causing sea levels to rise. The below graphic displays the carbon dioxide contained in ocean water off the coast of India and Bangladesh in the Indian Ocean. The dark red color denotes heightened levels of carbon dioxide in the ocean, and as the diagram shows, carbon dioxide levels remain quite high off the coast of Bangladesh, causing higher water temperature. Similar data for many different parts of the ocean can be found here.

Additionally, the warmer climate has led to increasing rates of glacier and sea ice melt. These events coincide to generate a rise in sea level which can have adverse implications on coastal environments and cities. For example, higher sea levels create deeper water that in turn generates larger storms and waves, damaging coastal cities and infrastructure. In addition to these costs, rising sea levels cause a number of biological damages including loss of habitat and biodiversity (NRC 55), coastal erosion (NRC 46), slowdown of ocean currents (NRC 45), and loss of sea ice. Many economic analyses of this issue focus only on the cost incurred by cities and infrastructure and thus may underrepresent the costs faced by society regarding rising sea levels.

Additional research has shown that the rate of glacial melt and sea-ice retraction has accelerated much faster than scientists had previously estimated. For example, separate reports from NASA and the University of Washington have recently discovered that the Western Antarctic ice sheet is past the point of return and will disappear completely in two centuries or more. The melting of this glacial sheet alone is projected to add twelve feet of water to rising oceans in addition to the melting already occurring. This finding adds to the increases in the rate of sea level rise found in the Intergovernmental Panel on Climate Change (IPCC) report released earlier this year that amended previous projections of sea level rise to reflect quickening rates of glacial melt and ocean warming. All these recent bodies of information show that sea levels are not only rising as a result of human-driven interactions with the environment, but the rate at which they do so is also increasing.

As mentioned above, there are many costs associated with rising sea levels, but one of the most pressing and potentially damaging involves the issue of coastal developments and whether to protect them. Although experts have varying opinions and findings regarding coastal development in the face of rising sea levels, all agree that without any action taken most coastal developments and cities will suffer crippling costs (See National Research Council 45). Given the rate of rising sea levels (prior to reports of the accelerated collapse of the Western Antarctic Ice Shelf) scientists had projected a rise of 28 to 61 cm (assuming aggressive action to reduce emissions of greenhouse gases) over the course of the twenty-first century. Taking this projection and applying it to analyses of coastal damage given certain levels of sea level rise provides an interesting insight on the projected costs to society:

This chart, taken from the NRC report on climate change, shows the cities along the coastal Southeast United States and their susceptibility to a 6-meter and 1-meter rise in sea level. As the diagram shows, many populous cities in the U.S. will be affected by rises in sea level, magnifying its problematic effect. The impact remains more significant in other parts of the world where the susceptibility to sea level rise is greater than that of the U.S. and the capability for mitigating harm remains significantly limited. For example, a recent article in the New York Times drew on research that projected rising sea levels will displace 18 million Bangladeshis by 2020. This begs the question: should current resources be allocated to areas of the world that have diminished capabilities to handle the costs of sea level rise? While this question may seem largely ethical in nature, it remains important to address it in possible solutions to rising sea levels. Currently, the largest impacts of sea level rise appear likely to hurt countries that have contributed little carbon dioxide to the warming oceans.

2008 global CO2 emissions from fossil fuel combustion and some industrial processes (million metric tons of CO2)

In conclusion, although much more data and research are required to enable effective action against rising sea levels, the data suggests the need for immediate actions to combat the problem. Investment to protect sea level rise in countries that cannot afford it would cost little to developed countries and could even have some benefits. However, regardless of where the public stands on climate change and rising sea levels, the evidence suggests that the time to take action is now.

References

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About the author: Christopher Malloy is a junior Economics major and Business Administration minor at the University of St. Thomas