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To maintain this level in the face of greater anticipated flows down the Rhine River (thanks partly to accelerated snowmelt in the Alps), the Dutch are radically revising traditional flood-management thinking. Instead of trying to contain floods, they will accommodate the extra water flow by allowing predesignated areas to flood. The strategy is called Living with Water. Near Nijmegen, the oldest town in Holland, a sparsely populated strip of land that is home to farms and a nature reserve will be allowed to flood to spare the more heavily populated areas downstream. Birds in the nature preserve can fly away until the waters recede, but not homeowners, who have protested. One lesson, says Bas Jonkman, an adviser to the Dutch Ministry of Water Management, is that "society must recognize that there will be losers from adaptation, and they must be compensated."
The greatest flood danger to the Netherlands comes from the North Sea, which is more powerful and unpredictable than the Dutch rivers. So, Dutch law has historically required North Sea defenses to deliver a 1-in-10,000-years level of protection. "And now the Parliament wants to raise the North Sea standard to a 1-in-100,000-years level of protection," says Pier Vellinga, a senior government adviser and professor at Wageningen University and Research Center. Vellinga calculates that to maintain this higher level of protection, the Netherlands would have to commit about 0.2% of its GDP annually--some $1.3 billion. The Dutch are straightforward about making adaptation to global warming a high priority. The alternative is the prospect of losing its coastal cities altogether. ("We Are Here to Stay" is the accompanying public slogan.) "We want foreign visitors and investment to keep coming to the Netherlands," Vellinga says, "so we must assure them this will remain a safe place."
The most visible example of BritishÂ commitment to adaptation is the Thames Barrier, a set of hulking but beautiful silver floodgates that stretch across the namesake waterway about 11 miles downriver from central London. When the Barrier became operational in 1983, 30 years after the massive flood that motivated its construction, planners expected that it might have to close once or twice a year to keep ocean-storm surges from inundating London. In the past decade, however, the Barrier has been closing an average of 10 times a year. "The Barrier was initially designed to offer a 1-in-2,000-years level of protection," says West of the UK Climate Impacts Program. "But sea-level rise is projected to reduce that to a 1-in-1,000-years level by 2030." In response, the British government is prepared to add 12 in. of protection on top of the existing floodgates--a contingency built into its original design--and to keep building patches and extending the Barrier as necessary. Planners in Britain assume it will have to be replaced within 100 years, but they don't yet know with what.
Adaptation isn't just about building a stronger physical infrastructure. A new urban village is being planned 120 miles north of London that will bring together mitigation and adaptation. "Bilston village will not only be a low-carbon-energy user, it will also try to make itself resilient to future climate changes," says West. For example, it will build flood protection into its design. "This could be a new model for how communities can walk on both legs into the climate future."
As a low-lying country that faces theÂ sea and drains 92% of the snowmelt from the vast Himalayan mountain range, Bangladesh is one of the most vulnerable places on the earth to global warming. Already, sea levels are rising in the Bay of Bengal and pushing salty water inland, lowering the productivity of rice cultivation in the south of the country. Farmers are adapting by switching land over to prawn farming, which tolerates saltier water.
"Bangladeshis have lived with flooding forever. It's part of our culture and essential to our agricultural system," says Saleemul Huq, who directs the climate-change program for the International Institute for Environment and Development. "In the past, we experienced a very big flood about once every 20 years," Huq says. "But in the last 20 years, we've had four very big floods--in 1987, 1988, 1995 and 2005. So it appears that the new pattern is to get a 1-in-20-year flood every five or 10 years." That increase has gotten policymakers' attention. After years of lobbying by Huq and his colleagues, the Ministry of Water Resources recently agreed to incorporate climate-change models into all future planning and decisions.
But because of its poverty--78% of its population lives on less than $2 a day--Bangladesh cannot afford the kind of defenses planned in Europe, or even New Orleans. As a matter of fairness, Huq says, adaptation measures in poor countries should be subsidized by rich countries. "It is poor countries that are suffering the brunt of climate change," he says, "but it is the rich countries' greenhouse-gas emissions that caused this problem in the first place." Britain is already subsidizing a substantial program in Bangladesh that will raise roads, wells and houses above the level of the last major flood. "Bangladesh is a showcase of what will happen under climate change," says Penny Davies, a diplomat at the British High Commission in Dhaka. "It amounts to a testing ground for what island states, including Britain, will need to do to protect ourselves in the years ahead."
By that same logic, the U.S. should beÂ trying to climateproof New Orleans. Much of the city is already below sea level, making its lessons all the more valuable for other coastal communities. Ivor van Heerden, director of the Louisiana State University Hurricane Center, has long urged a big-picture approach to hurricane protection. Restoring coastal wetlands, he says, is as important as building sound levees. During a hurricane, wetlands act like speed bumps, absorbing the force of incoming storm surges so that they are weaker when they reach inland. Louisiana's wetlands have been disappearing at an alarming rate because of imprudent levee building and oil-and-gas development.
Van Heerden calls his three-layered plan "defense in depth": "For your inner layer of defense, you put hardened levees or flood walls in front of major population centers or other high-value assets. You protect that inner layer with a middle layer comprised of as large an expanse of wetlands or swamp as possible. Finally, you protect that middle layer with a third layer--barrier islands out in the ocean proper, which also act to absorb and weaken storm surges."