Friday, March 27, 2009

Rising seas causing major U.S. economic impacts now; Hawai'i dodging bullet so far

Sea level rise and increasing hurricane strength are already having severe economic impacts on the East Coast—insurance companies have stopped issuing home insurance in extensive coastal areas.

“If you can't get insurance you can't do business, you can't own a home,” said Mike Tidwell, director of the Chesapeake Climate Action Network, a grassroots nonprofit that works on global warming impacts and solutions.

(Image: A century of sea level measurements in Honolulu. For sea level information across the state of Hawai'i, go here. Credit: NOAA.)

Allstate “has made a decision to retreat from coastal Maryland, parts of Virginia. And Liberty Mutual and State Farm have joined Allstate up and down the east coast from Massachussets to Florida in this retreat, directly and explicitly tied, according to them, to rising sea levels and bigger storms,” he said.

Hawai'i has thus far dodged this particular bullet, but experts are warning that severe impacts are coming.

Sea levels have measurably risen, and are continuing to do so. Shorelines are retreating. Low-lying areas are suffering inundation. And Hawai'i, like much of the nation, has done very little to prepare for the retreat of its shorelines.

“The tragedy is that there is so little planning for sea level rise in the United States,” Tidwell said. He joined two scientists in a recent audio conference on sea level rise. The conference, sponsored by the Rockefeller Family Fund, is available online at

One of their messages is that a lot of the projects being funded by the federal government's stimulus package are on land that will be under water within the lifetimes of today's young people.

Sea level expert Orrin Pilkey said that while current estimates differ somewhat, serious students of sea level are now looking at three to seven feet of sea level rise by 2100. The Dutch, whose below-sea-level provinces can't afford to get it wrong, are figuring on two feet in the next 40 years—during the working life of today's high school kids.

Pilkey is director of the Program for the Study of Developed Shorelines at Duke University. He said panels in Miami and Rhode Island figure a minimum sea level rise of 3 to 5 feet by 2100. And a book Pilkey and associated wrote figures it will be 6 to 7 feet by then—and it will keep going up.

For Hawai'i, local coastal geologist Chip Fletcher has concluded that these levels put much of Waikiki under water. Indeed, a lot of coastal Hawai'i, including low-lying beach parks, are at risk.

We're not alone.

Just a three-foot rise could lop off the entire southern tip of Florida, and destroy much of the Everglades National Park, the third largest park in the contiguous U.S., said Anthony D. Barnosky, environmental change expert and professor in the Department of Integrative Biology at the University of California, Berkeley.

The main driver of sea level rise in the past century has been thermal expansion of the oceans, Pilke said. Water expands as it warms. The main driver of rise in this century will be the melting of the Greenland and West Antarctica ice sheets, he said.

Much of the world is taking this issue far more seriously than the U.S.

Great Britain is talking about abandoning some of its coastal small villages. The Maldive Islands are discussing buying land in India or elsewhere to move their whole low-lying nation. New Zealand is agreeing to take refugees from flooding Pacific islands. The Dutch approach is an engineering one—armoring the shoreline to keep the ocean at bay.

Pilke said the U.S. can't really consider large-scale armoring—its coastline is far too long. And beach nourishment—like what has been done to add sand to Waikiki Beach—is a very temporary solution in a rising sea environment.

The only reasonable American response to continued sea level rise is to retreat from the shoreline, he said. That gets development out of the danger zone and preserves beaches for future generations.

The experts identified three key strategies for this problem.

One, as cited by Pilke, is retreat—moving critical infrastructure and population out of the low coastal area.

Another is engineering—developing critical coastal infrastructure (harbors, for example) so it can continue to function in a higher sea level environment.

And the third is to attack the cause—climate change. The speakers at the session agreed on a need to curb greenhouse gas emissions at all levels, push the move to non-carbon fuel sources and cap carbon emissions.

Said Tidwell: “The impact of sea level rise and global warming is already being profoundly seen and felt.”

©2009 Jan TenBruggencate

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