George Backus is a nuclear engineer, economist and systems researcher. He has served as an advisor to the U.S. Secretary of Energy, the U.S. Congress, the Canadian Prime Minister and many multinational corporations.
Backus currently leads a team at Sandia National Laboratories, in Albuquerque, New Mexico, that uses state-of-the-art climate and economic modeling to translate the likely range of climate change into the kinds of local, regional and national economic risks that lay people and policy makers can understand and work with.
In a recent interview, Bacchus explained how he and his colleagues think about risk, use data and models to estimate it, and provide people - from homeowners and farmers to movers and shakers - with facts and realistic projections that they can use to guide their decisions and actions.
Not surprisingly for researchers whose first mandate is making sure that mistakes involving nuclear weapons never happen, the Sandia Labs researchers take risks, including those posed by climate change, seriously. They start out by asking, "What are the implications of making the wrong assumption, of not knowing?"
What can we know about what we don't know?
Climate change critics often argue that because climate models are uncertain, taking action to slow climate change or head off predicted problems is a waste of resources and a misuse of governmental and economic tools.
As George Will writes, “Skeptics doubt that the scientists’ models, which cannot explain the present, infallibly map the distant future," . . . On such models we are supposed to wager trillions of dollars -- and substantially diminished freedom." (“The Climate-change travesty,” The Washington Post, December 6, 2009).
Bacchus and his colleague frankly recognize the limitations of climate models. They know that Earth’s climate is an enormously complex system, and so intrinsically difficult to predict.
Nonetheless, scientists have devoted years of intensive effort to gather the most accurate possible data about ancient climates as well as Earth’s current climate. They have created and refined intricate supercomputer models of the climate system, models that are capable of recreating many of the features of both ancient climates and current conditions, and of predicting likely futures.
But the best these models can do is to predict the range of climate conditions that are likely under different scenarios, for example if atmospheric greenhouse gases continue to rise at their current rates, or more slowly, or more rapidly.
George Will is right. None of the models can (or ever will) “infallibly map the distant future.” The question then becomes, what should we do in the face of that uncertainty?
The Greater the Uncertainty the Greater the Risk
Bacchus flatly rejects the idea that the uncertainty of climate change models means that we can ignore the risks they are alerting us to. Exactly the opposite is true, he says. “Instead of saying we don’t know, so why worry about it, we’re saying that yes, we’re not sure, but that’s why we should worry about it.”
He points out that climate models provide a range of possible outcomes. For example, most models predict that rising greenhouse gas levels will make already arid areas such as the American West or much of Australia hotter and drier. The models cannot predict that, for example, the Southwest will receive exactly 10 percent less annual precipitation between now and 2050, but it can provide probabilities of 5, 10, 15, 20, 25 percent, or deeper deficits.
The key point Backus makes is that the greater the uncertainty, the greater the risk of an extreme event, for example of a severe drought lasting a decade or more. Much like Hurricane Katrina, the economic and social impacts of an extreme event would be far more serious than just a series of smaller hot, dry spells.
“When we look at complex systems,” Backus says, “we find that it’s always the high end of what might happen – the tails of the distributions of events – that pose the greatest risk. In other words, what turns out to hurt us is not what we do know, but the range of what we don’t know.”
Backus sees it as the responsibility of climate scientists to gather the best data they can, create and utilize the best models they can devise, and provide policy makers and the public not with the illusion of certainty, but with the best estimates of the range of what climatic conditions people may face and their economic and social impacts.
Mapping Climate Change to Economics and Jobs
In a recent study, Backus and his colleagues took the range of rain and snowfall predictions from the best available climate models and translated them into state-by-state economic impacts. As described in more detail in “National Lab Calculates State-by-state Climate Risks,” (Suite101, July 24, 2010), they found that most states stand to lose economic activity and jobs as global warming continues, with at least $1 trillion of the U.S. gross domestic product and hundreds of thousands of jobs at risk, just from reduced precipitation. Agriculture and manufacturing, they point out, are particularly dependent on adequate water supplies.
The study provides realistic and detailed economic information to anyone who is concerned about the likely impact of climate change. More importantly, it provides that information in a form planners and even lay people are used to. A state legislature, for example, can debate whether it’s worth investing, say, $10 million researching drought resistant crops to insure against a $100 million crop failure.
The Sandia researchers will brief U.S. Congressional and Administration offices about these risks.
“Hopefully this allows people to have a common basis to think about the problem,” says Backus. “Our job is helping people to be risk-informed. How a state or nation sets its priorities is up to the policy makers, not to us.”
Source: George Backus et al., Assessing the Near-Term Risk of Climate Uncertainty: Interdependencies among the U.S. States. Sandia Report SAND2010-2052, May 2010..
Robert Adler - Robert Adler is a science and technology reporter and book author. He divides his time between Santa Rosa, California and Oaxaca, ...
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