The Tides They Are A-Changin’

, director of strategy & policy | October 11, 2012, 10:06 am EDT
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Even as all too many politicians continue to question the very existence of human-induced climate change, cities and counties in Florida and other coastal states are already struggling with the reality of sea level rise and are looking at billions of dollars in expenditures to deal with its impacts.

Today, more than 120 Floridians with expertise on sea level rise — scientists, engineers, city and county officials, and others — sent a letter to President Obama and Governor Romney, asking them to address sea level rise when they’re in Florida on October 22 for the final presidential debate in Boca Raton and to say what they would do to help Florida and other states deal with this very real threat.

Picture taken on October 7, 2010 in Miami, FL a result of extreme high tides, Courtesy of Miami Dade County Permitting, Environment and Regulatory Affairs

The letter notes that the eight-inch rise in sea level over the twentienth century “is now resulting in the flooding of city streets and parking areas at seasonal high tides, the abandonment of drinking water wells in coastal communities due to salt water intrusion, and the failure of flood control structures to operate during high tides.”

Looking ahead, the signers warn that “scientists project increased coastal and inland flooding and inundation, an increased likelihood of significant damage to key aspects of our urban infrastructure, and compromised drinking water sources in more and more communities.”

The biggest problems are occurring in southern Florida, particularly the Southeast, where porous limestone allows sea water to penetrate inland. For this reason, Broward, Miami-Dade, Monroe, and Palm Beach counties adopted a Southeast Florida Regional Climate Change Compact almost three years ago, committing to work together to advance both responses and solutions to climate change.

These counties are now in the process of adopting a Regional Climate Action Plan to deal with sea level rise and other impacts of climate change, as well as to reduce emissions from transportation, energy, and other sectors of the region’s economy. Some 5.6 million people — 30 percent of Florida’s population — live in these four counties, a population exceeding that of 30 states. Three other nearby counties (St. Lucy, Indian River and Martin) are beginning to work with these four counties on climate and sustainability issues.

But the problem extends beyond southeast Florida. Sanibel Island, west of Fort Meyers Beach, is losing its fresh water marshes — home to some endangered species — due to salt water intrusion. Hardwood forests along the west coast — north of Tampa Bay — are turning into saltwater marshes. The Tampa Bay Water Authority and the Peace River Water Authority, which provides water for Charlotte and Sarasota counties, are both wrestling with salt water intrusion on rivers they tap for drinking water. And as my colleague Brenda Ekwurzel noted in her Sea Level Rise is No Laughing Matter post, local sea level rise has increased so much since the Key West Airport was built, that during the “Super Moon” super high tide in May 2012 the airport was flooded with seawater.

An interactive map by Climate Central, based on their “Surging Seas” report earlier this year, graphically illustrates the threat posed by sea level rise to Florida and other coastal states.

The Florida experts end their letter with three specific questions for President Obama and Governor Romney:

  • What will be the federal government’s planning and policy priorities in order to reduce the risks of future sea level rise?
  • What will be the polices for adaptive measures to respond to current and future impacts of sea level rise?
  • How would you work with the rest of the world to address rising sea levels and other effects of climate change?

Tip O’Neill famously said that “all politics is local.” Given Florida’s perennial status as a presidential swing state, and the growing public prominence of the sea level rise issue, particularly in the southeastern part of the state, it will be interesting to see whether the presidential candidates respond to these questions during the closing weeks of the campaign.

Map: © Union of Concerned Scientists 2012

Images: Courtesy of Miami Dade County Permitting, Environment and Regulatory Affairs.


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  • Rick: Thanks for your question. The following statement was made on page 18 of the 2009 publication Global Climate Change Impacts in the United States (Thomas R. Karl, Jerry M. Melillo, and Thomas C. Peterson, editors, Cambridge University Press), put out by the US Global Change Research Program that represents 13 federal agencies: “After at least 2,000 years of little change, sea level rose by roughly 8 inches over the past century.”

    This rate of global sea level rise over the last century is consistent with the record according to Florida tidal gauges. There’s a link to the NOAA Key West tidal gauge in endnote #1 in the Florida sea level rise experts’ letter, at,%25 Here’s the bottom line: “The mean sea level trend is 2.24 millimeters/year with a 95% confidence
    interval of +/- 0.16 mm/yr based on monthly mean sea level data from
    1913 to 2006 which is equivalent to a change of 0.73 feet in 100 years.”

    As Daniel Patrick Moynihan famously said, “everyone is entitled to their own opinions, but not their own facts.” To me, what’s truly insane and delusional is the continued call by some that we not respond urgently to the overwhelming weight of the scientific evidence on this issue, both by taking measures to cope with the climate impacts we are already experiencing and by limiting emissions of the heat-trapping gases that scientists tell us are driving even greater impacts in the future.

  • Rick Spung

    are you seriously going to suggest sea levels rose EIGHT inches during the twentieth century??? that’s insane. delusional. laughable. pathetic.