A Recipe for Disaster: Climate, Coastal Urbanization, and Water

Major population shifts from rural to urban areas are creating challenges for many environments and landscapes, especially along the coasts where 35 of the 50 largest cities in the world are located, said Geoffrey Scott, Chairman of the Department of Environmental Health Sciences at the University of South Carolina.

Scott spoke at the Metcalf Institute’s 2015 Public Lecture Series, highlighting how many of these challenges are collectively brewing what he called “a recipe for disaster” for America’s coastal communities.

Every eight months, the amount of oil that runs off roads into U.S. waterways is equivalent to the amount of oil spilled in the Alaskan Exxon Valdez spill (11 million U.S. gallons).

Nearly all of Earth’s natural hydrological, nitrogen, and phosphorus cycles have been compromised by urbanization in recent decades, Scott said, using as an example his home state of South Carolina, where the city of Charleston’s population doubled in just 20 years, doubling the city’s urban geographic footprint as well. Paving residential lots and commercial zones presents a direct threat to water quality; as Scott noted, “just a 10 percent increase in imperviousness will decline water quality,” and anything above this point will begin to influence ecosystem functions.

Charleston, S.C., waterfront

The population of Charleston, S.C., doubled in 20 years. Photo by Ron Cogswell.

Actions on land have a way of spreading their impact to other parts of the environment, Scott argued. In the case of a coastal, estuarine environment, the potential for destructive impacts from continued growth is high. Every 8 months, the amount of oil that runs off roads into U.S. waterways is equivalent to the amount of oil spilled in the Alaskan Exxon Valdez spill. This correlates with the fact that 44 percent of estuaries in the U.S. are impacted by some form of non-point source pollution, according to Scott. In turn, 40 percent of all U.S. shellfish beds have some form of annual restriction related to declining water quality. And, he added, that urbanization only adds to the demonstrated environmental degradation posed by climate change.

The picture that Scott painted is a grim one, but as he explained, recognizing the problems posed by urbanization is a step in the right direction. The goals are in place and the obstacles are clear, he said, but the solutions to healthy, conscious urban growth on the coastline are still being established.