Rising Sea Levels Raise Risk of Record Floods

Sea level rise from global warming has greatly increased the risk of coastal flooding, according to new research published this week. The effects of global warming have doubled and in some cases tripled the chances of “once in a century” flooding occurring by 2030 in many areas of the coastal U.S.. At most sites studied, “century” flood levels reach over four feet above high tide line. Some 5 million Americans live in homes less than four feet above the high tide line and are at risk from these record-breaking floods.

The Surging Seas study projects sea level rise in the continental US of one to eight inches by 2030, and 4 to 19 inches by 2050, with much depending on how human society reacts to the global warming threat by cutting back on carbon emissions.

Report lead author Dr. Ben Strauss commented, “Just a small amount of sea level rise, including what we may well see within the next 20 years, can turn yesterday’s manageable flood into tomorrow’s potential disaster. Global warming is already making coastal floods more common and damaging.” The research was published in two articles in the journal Environmental Research Letters by scientists at Climate Central, the University of Arizona and the National Oceanic and Atmospheric Administration.

Florida Most at Risk

Unsurprisingly, the long, low coast of Florida is most at risk.  The report notes “A preliminary independent analysis suggests about $30 billion in taxable property is vulnerable below the three-foot line in just three counties in southeast Florida, not including the county with the most homes at risk in the state and the nation, Miami-Dade.” The Climate Central website includes fact sheets for potentially affected states.  It estimates that  California faces three times the risk of catastrophic flooding due to global warming-induced sea level rise, and estimates that 374,000 people are at risk from flooding.

The research points out that human actions around adaptation to sea level rise scenarios can mitigate or enhance negative effects: “For example patterns of development will probably play one of the strongest roles in both the short and long terms. At the highest level, the amount of population and infrastructure potentially under threat will depend on whether low-lying coastal development continues unabated  or, at the other end of the spectrum, communities begin to retreat. At a secondary level, adaptive measures such as enhancing ecological buffers or building levees or seawalls will influence vulnerability, and already do so today.”

Prohibitive Costs

Beyond human and animal misery, there will be huge costs associated with increased flooding and sea level rise. The New York Times reports “Insurance companies got out of the business of writing flood insurance decades ago, so much of the risk from sea level rise is expected to fall on the financially troubled National Flood Insurance Program, set up by Congress, or on state insurance pools.” Ultimately U.S. taxpayers will pay much of the cost of inundations’ property damage and relocation.

Is Your Home In Danger?

Climate Central has an interactive map that uses data from NOAA, the Census and the US Geological Survey to illustrate flood risk scenarios by state, city or zip code. The organization’s website also offers downlaods of the data set used to create the map, and solicits personal stories of coastal flooding from users.

Global Risks

The U.S. coastline is by no means alone in facing the risks from accelerating global warming. A report released yesterday by an Australian government agency confirmed that Australia is getting hotter while facing a quickening sea level rise and shifting rain patterns. An unpublished UK government report obtained by the Guardian this week reveals that up to 12 of Britain’s 19 nuclear sites are at risk of flooding due to rising sea levels caused by global warming.