During the past year, scientists have noted that polar ice sheets are melting much faster than anticipated. The IPCC’s next comprehensive report, due in 2007, is expected to lower the worst-case scenario.īut these estimates exclude Antarctica and Greenland’s future contributions to sea level rise, says Greg Carbone, a USC geographer. In 2001, the Intergovernmental Panel on Climate Change (IPCC) noted that it’s possible, though very unlikely, that global sea level could rise by as much as three feet by 2100. Numerous studies have estimated-based on computer models-how high and how quickly sea level could go up. How much carbon dioxide would, for example, set off a chain reaction of warming that would drive up sea levels and drown coastal cities? Some scientists have argued that 500 parts per million would push the world into real trouble others say 450 still others say 400. Melting land-based ice sheets and land-based glaciers in Antarctica and Greenland send pulses of freshwater into oceans.Ĭlimatologists are trying to estimate which threshold of atmospheric carbon dioxide would spawn accelerated global warming and cause environmental and social catastrophes. These concentrations will continue to rise for some time, potentially causing abrupt ecological disruptions.Ī hotter climate drives up global sea level by expanding seawater this is called thermal expansion. Consensus reports by climate scientists and scientific organizations predict that over the next century climate change will almost certainly gain momentum.Ĭarbon-dioxide levels in the atmosphere have increased from 280 parts per million before the industrial revolution (which began about 1750) to 380 parts per million today. Increased greenhouse gases add to the layer in the atmosphere that traps some of the sun’s heat, further warming the Earth. In June 2006, a special committee of the National Academies of Science pointed out that there are “multiple lines of evidence for the conclusion that climatic warming is occurring in response to human activities.”ĭozens of peer-reviewed studies in prestigious journals have documented the crucial role of carbon dioxide and other greenhouse gases in heating the planet. What is so different about today is that human activities are a major driver of global warming, although natural variability also has a role, according to leading climate scientists. There is a growing scientific consensus that global sea level will rise faster because of climate change.įor the past 18,000 years, since the end of the last Ice Age, global sea level has gone up about 360 feet in fits and starts. We’ll see even more of all this in the future. Salt water is moving up some streams and rivers, damaging freshwater swamps and creating “ghost forests” of dead trees. Today some salt marshes are drowning, and so coastlines are losing wildlife habitat and nursery grounds for commercially important fisheries such as shrimp and blue crab. Property owners who build walls to prevent erosion along tidal creeks can increase erosion in downstream areas. Rising sea level is already making some salt marshes migrate inland, exposing coastal structures to more flooding. People who invest in these vulnerable coastal properties really should know their risks.” “In most cases, we’re talking about a period longer than a 30-year mortgage before people see huge changes. Morris, a marine scientist and director of the University of South Carolina Belle W. “Some South Carolina coastal wetlands will likely drown within the next 50 years,” says James T. Developers are constructing single-family houses, condominiums, restaurants, and marinas in places just above high tide, transforming the state’s salt-marsh edges.ĭuring recent hurricanes, coastal residents learned, once again, that living near the ocean is dangerous. Investors are snatching up lower reaches of the lowcountry -acre upon acre of temporarily solid ground sloping toward the pluff mud of South Carolina’s coastal wetlands.
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