It has been a record year for weather-related disasters in the United States, from historic drought in Texas to record-breaking floods in North Dakota, and the risk of such extreme events is likely to keep rising, experts said at a recent Capitol Hill briefing that AAAS helped organize.
While it is impossible to say if climate change is responsible for a specific weather event, the experts said, it probably is increasing the intensity of some disasters such as the Texas drought. And whatever the causes, the financial losses from such events are increasing as more people live in vulnerable areas.
Since the future is inherently uncertain, it is not particularly useful to debate whether a specific weather event is caused by climate change, said Jay Gulledge, senior scientist at the nonprofit Center for Climate and Energy Solutions (C2ES). What matters, he said, is whether there are statistical trends that are consistent with scientists’ expectations of climate change. Such trends are happening for some types of extreme weather, Gulledge said.
John Nielsen-Gammon, the Texas state climatologist and a professor of atmospheric science at Texas A&M University, said climate change probably did make the Texas drought more intense (by adding about 1 degree Fahrenheit to annual average temperatures in the state). And drought as severe as this year’s could be more likely as a result of climate change, he said, although more research is needed to confirm that.
But Nielsen-Gammon said the triggering event for the current Texas drought is La Niña, cooler than normal sea-surface temperatures in the central and eastern tropical Pacific that can affect global weather patterns. The drought is expected to continue at least through next summer, he said.
Meanwhile, public officials and private citizens need to be better prepared for future extreme events, Gulledge said. “This is a risk problem, and we have to manage it as a risk problem,” he said at the 2 December briefing, “Drowning and Drought: Extreme Weather Impacts on Our Economy and Society.” The event, attended by several dozen Capitol Hill staffers and others, was organized by AAAS’s Office of Government Relations, the American Geophysical Union, and C2ES (formerly the Pew Center on Global Climate Change).
The need to better prepare for extreme weather events also was the impetus behind a new report from the Intergovernmental Panel on Climate Change (IPCC), said Michael Oppenheimer, professor of geosciences and international affairs at Princeton University and coordinating lead author of the report. He said the report marked an unusual collaboration among disaster management specialists and scientists who have been looking at ways for societies to adapt to changing climate.
“These two communities had to get together and make some suggestions to policy-makers,” Oppenheimer said. In a summary released 18 November, the report’s authors urged better preparation for “unprecedented extreme weather” caused by global warming.
Scientists attribute the warming largely to the buildup of heat-trapping greenhouse gases from burning of fossil fuels and other human activities. The report predicted that heat waves that now are once-in-a-generation events will become hotter and happen once every five years by mid-century and every other year by the end of the century. It also said very heavy rainstorms that usually happen once every 20 years will become far more frequent. Without better preparation, some locales may be overwhelmed by extreme weather events, the report said.
“To put it bluntly,” Oppenheimer said, “we are doing a lousy job, as of today, in keeping up with disasters.”
While weather disasters may be triggered by events such as tropical storms or prolonged drought, Oppenheimer noted, the financial losses are largely determined by two other factors: exposure, or the number of people living in the path of an extreme event such as a powerful Atlantic hurricane; and vulnerability, or how well buildings, utilities and other facilities can withstand the impact of such events.
Hurricane Katrina, which destroyed or damaged much of New Orleans in 2005, was an object lesson on how exposure and vulnerability—along with a devastating triggering event—can lead to billions of dollars in damages and many deaths, Oppenheimer said. He also cited Atlantic City as a prime example of bad exposure: billions of dollars worth of buildings perched at the ocean’s edge.
But Oppenheimer said nations and communities can take steps to reduce the risk of future weather-related catastrophes. “You don’t have to just stand there are take it,” he said. “There are things that can be done better to save lives, save money. And that is the bottom line of the report, even in the face of the need to also reduce the emission of greenhouse gases.”
While mitigation—the reduction of greenhouse gases—has been the main focus of climate change discussions in recent years (including the recently concluded climate talks in Durban, South Africa), attention also has been shifting to adaptation, a strategy that makes sense for coping with extreme weather as well as the longer term disruptions expected from climate change.
Oppenheimer cited some adaptation success stories. Europe suffered a devastating heat wave in 2003, with an estimated 25,000 to 70,000 deaths. Three years later, sections of France experienced similar heat, but death rates were 10 to 100 times lower, Oppenheimer said. “Governments got their act together,” he said, by providing earlier warnings about excessive heat, supplying water to those in need, and establishing air-conditioned shelters for the elderly and others at risk.
Oppenheimer also cited steps by Bangladesh to reduce fatalities from cyclones that regularly hit that nation on the Bay of Bengal. In 1970, flooding from a storm killed at least 500,000 people, according to some estimates. Oppenheimer said it could have been closer to a million. Death tolls in Bangladesh from major storms now are in the thousands, still a major concern. But early warning systems and widespread construction of sturdy concrete evacuation shelters have diminished the impact of extreme weather events.
“Just these relatively small improvements have saved lives,” Oppenheimer said.
The world business community is grappling with the risks of extreme weather and climate change, according to Frank Nutter, president of the Reinsurance Association of America. He noted that the World Economic Forum’s Global Risk Survey places the perceived economic impact of climate change toward the top of the risk list, just below “fiscal crises” and ahead of such fears as “extreme energy price volatility” and “global governance failures.”
Nutter agreed that weather-related risks in the United States are driven by “where we live and how we live.” The value of property at risk has risen dramatically he said, and natural disasters in just the first six months of 2011 accounted for nearly $100 billion in losses. Through November, there were a record 12 disasters in the United States alone that each caused in excess of $1 billion in losses, according to the National Climatic Data Center.
There has been “a pretty dramatic rise” in the number of extreme weather events in recent years, Nutter said. “Global extreme weather losses, by number of events, are three times greater now than they were in 1980,” he said. In the United States, hurricanes accounted for $153 billion of insured losses from 1991 to 2010. Flood losses tripled over the same period, Nutter said, and wind losses doubled. Average annual winter storm losses have increased more than 50% since 1980.
“We don’t know yet what the new normal is going to be,” Nutter said, “but the industry sees a pattern of losses that is rather extraordinary.”
Given that situation, it is essential to be more forward-looking in risk assessment, he said. While capping greenhouse gases makes sense, he said, the insurance industry has focused on adaptation strategies. They include building safer homes and structures under building codes that take into account possible natural catastrophes. People also should pay insurance premiums based on the level of risk they take, he said.
In particular, Nutter spoke of the need to address repetitive losses in flood-prone areas. He said that about 2% of the properties covered under the federal flood insurance program account for about 30% of the losses. In many cases, structures are rebuilt again and again after weather events. “Some sort of program that buys them out or moves the homes would be an important public policy goal,” he said.
All of the speakers agreed that the extreme weather events of 2011 should prompt more determined efforts to assess and manage risks in an uncertain future. As Oppenheimer put it: “We are under pressure because the climate is changing. We have to use our brains.”
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