Many scientists share Hedin's worry. "The real honest message is that while there is debate about how much extreme weather climate change is inducing now, there is very little debate about its effect in the future," says Michael Wehner, staff scientist at Lawrence Berkeley National Laboratory and member of the lead author teams of the interagency U.S. Climate Change Science Program's Synthesis and Assessment reports on climate extremes. For instance, climate models predict that by 2050 Russia will have warmed up so much that every summer will be as warm as the disastrous heat wave it just experienced, says Richard Seager of Columbia University's Lamont–Doherty Earth Observatory. In other words, many of today's extremes will become tomorrow's everyday reality. "Climate change will throw some significant hardballs at us," says Martin Hoerling, a research meteorologist at the National Oceanic and Atmospheric Administration's Earth System Research Laboratory in Boulder, Colo. "There will be a lot of surprises that we are not adapted to."
One of the clearest pictures of this future is emerging for the U.S. Southwest and a similar meteorological zone that stretches across Italy, Greece and Turkey. Work by Tim Barnett of the Scripps Institution of Oceanography, Seager and others predicts that these regions will get hotter and drier—and, perhaps more important, shows that the change has already begun. "The signal of a human influence on climate pops up in 1985, then marches on getting strong and stronger," Barnett says. By the middle of the 21st century, the models predict, the climate will be as dry as the seven-year long Dust Bowl drought of the 1930s or the damaging 1950s drought centered in California and Mexico, Seager says: "In the future the drought won't last just seven years. It will be the new norm."
That spells trouble. In the Southwest the main worry is water—water that makes cities like Los Angeles and Las Vegas possible and that irrigates the enormously productive farms of California's Central Valley. Supplies are already tight. During the current 11-year dry spell, the demand for water from the vast Colorado River system, which provides water to 30 million people and irrigates four million acres (1.6 million hectares) of cropland, has exceeded the supply. The result: water levels in the giant Lake Mead reservoir dropped to a record low in October (before climbing one foot, or 30 centimeters, after torrential winter rains in California reduced the demand for Colorado River water). Climate change will just make the problem worse. "The challenge will be great," says Terry Fulp, deputy regional director of the U.S. Department of the Interior's Bureau of Reclamation's Lower Colorado Region. "I rank climate change as probably my largest concern. When I'm out on my boat on Lake Mead, it's on my mind all the time."
The Southwest is just a snapshot of the challenges ahead. Imagine the potential peril to regions around the world, scientists say. "Our civilization is based on a stable base climate—it doesn't take very much change to raise hell," Scripps's Barnett says. And given the lag in the planet's response to the greenhouse gases already in the atmosphere, many of these changes are coming whether we like them or not. "It's sort of like that Kung Fu guy who said, 'I'm going to kick your head off now, and there's not a damn thing you can do about it,'" Barnett says.
Although efforts to fight climate change are now stalled in Washington, many regions do see the threat and are taking action both to adapt to the future changes and to try to limit the amount of global warming itself. The Bureau of Reclamation's Lower Colorado Region office, for instance, has developed a plan to make "manageable" cuts in the amounts of water that the river system supplies, which Fulp hopes will be enough to get the region through the next 15 years. In Canada, after experiencing eight extreme storms (of more than one-in-25-year intensity) between 1986 and 2006, Toronto has spent hundreds of millions of dollars to upgrade its sewer and storm water system for handling deluges. "Improved storm drains are the cornerstone of our climate adaptation policy," explains Michael D'Andrea, Toronto's director of water infrastructure management.