How Climate Change Is Altering American Coastlines Kevin Gardner Science & Medicine America’s coastlines are highly populated areas. Upwards of 25 million Americans are at risk for coastal flooding, and an even greater share of Americans could be adversely affected by climate change if droughts and mass migration are factored into the picture. In one way or another, over half of the nation’s economy—measured by national gross domestic product—is tied into coastal economic activity. Offshore drilling, fishing, and tourism form the bulk of all of this activity. Areas like these—as well as the transportation of goods from one part of the country to another and resource extraction near the coasts—could be imperiled by climate change in the coming decades. Already we are seeing some disruptions to business as usual. Aside from these economic considerations, climate change is adversely affecting local ecosystems and the animals that depend on their stability. Greenhouse Gas Emissions Making Matters Worse Coastal areas tend to suffer the brunt of humans putting more carbon dioxide and other greenhouse gas emissions into the environment since these are the areas that are quickest to feel the effects of severe weather events. A higher frequency of severe hurricanes on the east coast and more wildfires, mudslides, and flooding on the west coast are just a few of the ways in which climate change is changing things for coastal residents. As time goes on, we can expect to see greater disruption to local ecosystems and coastal economies. As ocean surface temperatures rise beyond a sustainable level, the oceans themselves become more acidic. This acidity causes the oceans to absorb more carbon dioxide, thus creating a vicious circle that perpetuates the disruption to coastal economies and local ways of life. Most of the latest climate change news is also focusing on the fact that climate change could worsen a lot of pre-existing problems. Coastal flooding and shoreline erosion catalyzed by climate change could likely get worse in the years to come. Already climate change experts are seeing a sign of things to come in coastal areas in other parts of the world. The country of Bangladesh and the island nation of Maldives are facing an escalating and frightening increase in shoreline erosion, which is causing a greater share of their respective populations to seek out safer areas. Mass migration is something that these countries are already experiencing, and the same could be just around the corner for coastal areas of the United States. 94,000 Miles of Coastal Land Could be Jeopardized Changing of the coastal marshes and wetlands is also a distinct possibility in the near future if steps aren’t taken to combat climate change, according to the Environmental Protection Agency. The quality and availability of water could also drop precipitously if greenhouse gas emissions are not quickly gotten under control. Lower oxygen levels near the coastal wetlands and greater levels of ocean acidification could affect the number of coastal storms and local ecosystem disruptions. The areas of the United States that the National Climate Assessment has started to warn Americans about have already experienced their share of difficulties over the last two years. The city of Houston was brought to its knees last year when Hurricane Harvey brought millions of gallons of water through its downtown. Storm surges, flooding, and related vulnerabilities threaten parts of the west coast, especially San Francisco, as well. The United States has 94,000 miles of coastal land that could be seriously affected if greenhouse gas emissions are not brought under immediate control. Featured image courtesy of Library of Congress.