WASHINGTON – Install massive steel barriers in the waters around New York City to ward off storm surges as sea levels rise. Plant heat-friendly corn instead of heat-sensitive wheat. Air-condition stifling apartments to prevent widespread heat-related deaths. Require new buildings to be set well back from the seashore or raised on stilts.
These are some of the ideas that scientists and engineers are discussing to help the world adapt to climate change. No matter what efforts are made to slow global warming, even many skeptics say that further temperature increases are inevitable.
As a result, adaptation – actions that individuals, companies or governments take to reduce damage from climate change – is gaining more attention from researchers and policymakers.
“We have already bought into a certain amount of climate change,” said Jay Gulledge, a senior researcher at the Pew Center on Global Climate Change in Arlington, Va. “Adaptation is obviously something we’re going to have to do.”
“Without adaptation, the consequences of global warming and sea level rise would be disastrous,” the Intergovernmental Panel on Climate Change warned in its most recent five-year report.
Adaptation isn’t a substitute for measures to control carbon dioxide and other greenhouse gas emissions, which most scientists believe have increased average global temperatures by about 1.4 degrees Fahrenheit over the past century. If emissions continue to grow at the present rate, scientists say, the Earth could become 3 to 5 degrees warmer by the year 2100.
“Climate change policy requires that both of these issues (adaptation and carbon reduction) be addressed simultaneously,” said Robert Mendelsohn, an environmental scientist at the Yale School of Forestry & Environmental Studies in New Haven, Conn. “Countries should prudently anticipate warming and prepare to adapt to climate change.”
Adaptation can include such measures as switching crops, building seawalls, controlling water use, adopting new building codes, even moving away from danger zones.
People, of course, have always adapted to changes in their environment. Half a million Oklahomans and other Southwesterners migrated to California during the Dust Bowl droughts of the 1930s. Thousands of New Orleans residents will never return to their Hurricane Katrina-devastated city.
As the United States gets hotter, people will try to move north, Gulledge predicted. “Unfortunately, all the good places are already taken,” he said. As a result, “Canada will be more populous 500 years from now.”
Animals, plants and insects already are migrating toward cooler climes. Since 1975, 1,700 biological species have been moving poleward at an average speed of 25 miles per decade, James Hansen, a NASA environmental scientist, reported in last week’s edition of the Proceedings of the National Academy of Sciences.
There will be winners as well as losers as humans try to adapt to a hotter world. Many farmers are likely to benefit. “Higher carbon-dioxide levels will increase crop productivity,” Mendelsohn said.
On the other hand, poor countries that lack the capacity to adapt will be worse off. For example, people on low-lying islands may find their homes uninhabitable.
“There is an urgent need to help vulnerable communities adapt to the sea level rise, which is already under way,” Achim Steiner, the executive director of the United Nations Environment Programme, said in a report in August on the plight of Pacific Ocean islands. Some islands, such as Fiji and American Samoa, already have lost much of the mangrove swamps that protect their coastlines.
Many of the world’s major cities lie close to the sea and are threatened by rising water. Venice, Italy, and St. Petersburg, Russia, are building huge barriers to protect themselves. London has installed a series of locks to block tides surging up the River Thames.
For more than five years, Malcolm Bowman, an oceanographer at the State University of New York at Stony Brook, Long Island, has been promoting the idea of placing four 50-foot-high storm-surge barriers in the rivers and harbors surrounding New York City. Parts of the city lie only a few feet above the Atlantic Ocean and are subject to severe flooding in storms. Federal, state and local agencies are helping to finance Bowman’s study.
According to Bowman, the surge gates would be left open for ship traffic, but when a storm threatened they could be closed for a day or two until the worst danger passed.
“It sounds kind of fanciful, I know,” Bowman said. “It would be a huge engineering project. It would cost billions. But 100 years down the road, our descendants are going to have to decide either to build or to retreat.”
Another huge engineering project under discussion is a proposal to divert the mouth of the Mississippi River to rebuild wetlands threatened by rising water south of New Orleans. The Louisiana Department of Natural Resources and the U.S. Corps of Engineers will hold a brainstorming session on the idea this fall.
“We have already bequeathed a more dangerous world to our grandchildren,” Neil Adger, a climate expert at the University of East Anglia in England, wrote in his new book, “Fairness in Adaptation to Climate Change.” “Adaptation to climate change will be required from all of us, whether we want it or not.”