Sealevel Change As A Global Problem

Given the growing concern about, and possible evidence of, global warming, there has been considerable speculation about the potential impacts on coastal areas of a sea-level rise related to global warming. Scientists who participated in the 1995 Intergovernmental Panel on Climate Change (IPCC) Report (IPCC, 1996) suggested that global sea level may well increase by an additional 15 to 70 cm (6 to 27 inches) by the end of the 21st century. The exact amount of rise would depend on the actual increase in global temperatures. Clearly, any additional increase in sea level could have devastating consequences for coastal communities.

All states that border bodies of water, whether along the global oceans or inland seas, should pay attention to fluctuations in sea level as well as to the rise in sea level linked to global warming. Inland seas, for example, can be viewed as living bodies in the sense that they can expand and can shrink. These changes can occur on different time scales: from daily to seasonally, from a year to a decade, or a century, or a millennium. In fact, they fluctuate and change on all these scales. The same can be said of the open oceans, but they tend to fluctuate on much longer time scales than do the inland seas, over periods of many decades and centuries. Such time scales are difficult to factor into the thinking of economic development planners, whose time frames are on the order of years to a few decades at most.

In essence, one can consider the Caspian as a laboratory of sea-level change and its potential societal and environmental consequences. For the Caspian to serve as a true "laboratory," its environmental-monitoring network, which collapsed with the breakup of the Soviet Union, must be restored and maintained by regional cooperation among the Caspian states. Impacts on ecosystems that are managed (farms and pastures) and unmanaged (wetlands, forests, deserts) can be identified. Effective human responses to changes in the coastal zone (both land and sea) can also be identified and assessed; environmental engineering proposals to deal with sea-level changes (such as seawall construction, higher oil platforms in the sea, diversion of water from the Caspian to the drying Aral Sea) can be evaluated for effectiveness, taking into consideration the scientific uncertainties surrounding sea-level fluctuations.

Whether the global climate gets warmer, cooler, or stays as it has been for the last several decades, the level of inland seas will likely continue to fluctuate (the mean ocean level has already gone up by 5 to 6 inches in the twentieth century alone). Societies must learn to cope with both short- and long-term fluctuations. In the Middle Ages, people in the Caspian region were not allowed to settle too close to the sea's shore, under the threat of death. Apparently, leaders were then aware of the dangers that the Caspian's fluctuating levels posed to their citizens. Today's leaders would be well advised to pay attention to traditional wisdom.

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