Monday, Jun 1, 2009 10:30 AM UTC

The seldom-seen devastation of climate change

A NASA climatologist explains why global warming is more than starving polar bears, and skeptics are simplistic.

In our visual culture, climate change remains oddly invisible. Few people can glimpse melting glaciers or perceive that seas levels are rising. We may feel hotter, but we cannot see carbon rising through the atmosphere as we drive our cars around. This is one reason for our lethargic response to the problem: out of sight, out of mind.

“Climate Change: Picturing the Science,” a new book by Gavin Schmidt and Joshua Wolfe, aims to alter that by providing a rich photographic record of a warming world. Some photos tell a self-evident record of geophysical change, like a shot of Lake Powell, on the Arizona-Utah border, where warming-induced drought has produced a dramatically lowered water line — a yellow “bathtub ring” of once-submerged rock.

In other cases, knowing a little about our climate can affect the way we interpret these photos — lending a more menacing air to seemingly benign images. An aerial shot of a massive Dutch sea barrier, with the city of Rotterdam lying just beyond, looks like an ode to Sisyphean futility. A gorgeous photo of sunlight striking a glacier in Peru’s Quelccaya ice cap symbolically sums up a larger question: How long will such formations resist the effects of the sun?

To provide some of that knowledge, Schmidt, a climatologist at NASA’s Goddard Institute for Space Studies in New York, wrote a few accompanying essays and solicited several others from colleagues. The book emphasizes the complexity of the climate change problem, noting the wide range of greenhouse gases that engender warming (not just carbon dioxide but also methane, aerosols and more), the many ways we release them, and the varied regional effects they produce. Climate change is not a one-dimensional problem with a simple solution, so we need to grasp the totality of the global climate system.

Salon spoke to Schmidt about our inability to grasp global warming, the nature of climate science, and our prospects for a cooler future.

Why is it important to depict climate change visually?

The imagery associated with climate change often veers toward the overly dramatic. That isn’t to say climate change is not dramatic. But people get the idea that climate change is all about polar bears and hurricanes. What we tried to do was to find images that showed the relationship between climate change and people and that brought out some of the long-term nature of changes and its complexity. Small things that happen because of climate change end up having big effects.

What’s a small change in nature that leads to a larger problem?

Pine-bark beetles. They are a pest for lodge-pole pine trees in Colorado up through British Columbia to Alaska. They are very sensitive to cold. If it doesn’t fall below minus 20 Celsius [minus 4 degrees Fahrenheit] for a week or two during the winter, they reproduce rapidly. As the winters have gotten warmer, the range of the beetles has expanded enormously, much faster than their predators. If you visit Colorado, behind the Front Range, you’ll see whole hillsides devastated by these pine-bark beetles. In British Columbia and Alaska, it’s huge thousand-mile tracts of forest. These changes have been leading to forest fires, because now you’ve got more fuel, which increases carbon emissions.

Beyond fixating on polar bears, what else are we missing about climate change?

There’s still a lot of confusion about the role of humans. If you look at opinion polls, people are much less aware of our role in pushing climate change forward than the scientific community or even policymakers. And we’re trying to make clear it’s a multifaceted problem. It’s not just carbon dioxide but methane emissions, black carbon and aerosols. It’s not just you driving your SUV that’s causing it.

People also see the conclusions of science, but they don’t see the process of science. When somebody tells them what scientists say, there’s a knee-jerk reaction: “Who the hell are scientists to be telling us these things?” So we try very hard to give a sense of how scientists really go about their detective work. How do you piece together a hugely complex situation like the earth’s climate?

I think a big problem is that we often view science as a source of fixed facts. For a lot of us, high school biology just involved memorizing the parts of a cell. Whereas climate science is more about analyzing cause and effect in a complex system, adding information in, understanding results we measure as probabilities.

This is reinforced all the time in popular culture. And the way we teach science is that Newton said “X” and it’s correct, so learn this formula. This promotes the idea that science knows all the answers. Whereas when you look at any actual working scientist, whether it’s in climate change or medicine or building a nuclear power plant, the stock in trade of science is uncertainty; it’s not certainty.

Niels Bohr said, “Prediction is difficult, particularly when it’s about the future.” People demand certainty from scientists they would never demand from any other field of life. In economic policy, with the stimulus package, are we saying, “This will fix everything”? No, there are all these variables like consumer confidence, and people understand it’s a complex problem. Yet when it comes to something slightly more scientific, you often hear that unless the science is 100 percent certain, it’s not worth listening to.

People clearly recognize the limits of scientific knowledge in medicine. One reason we use a medical analogy in the book — symptoms, diagnosis, cures — was to tap into this. We have symptoms, the doctor prods and pokes and says, “Let’s have a follow-up test,” and then comes back with, “Well, maybe you need to cut down on your cholesterol. Maybe you can take this drug. It might have side effects.” People don’t expect a doctor to predict exactly the day that they’re going to die, or even exactly what they have. Doctors have an enormous body of knowledge that allows them to treat people with beneficial effects, but there’s no guarantee. People understand that.

I’m not sure people don’t expect more from doctors. But doesn’t the analogy work if we simply talk about medical research? In the United States 15 or 20 years ago, people thought power lines caused cancer, or today it might be cellphones. And to find out, we have to study a complex interaction of the body with the environment. But then maybe we end up inferring the answer — and anyway, it’s a matter of probability, from one person to another.

The way you would test if cellphones really cause cancer is that you’d have one section of the population use cellphones all the time, and then you’d have a control group not allowed to use cellphones, and you’d measure the rate of cancer in each group. Partly due to ethical considerations, that’s never going to happen. So our conclusions are pieced together from epidemiological evidence, from models for how the brain reacts to electromagnetic radiation, animal analogs, all sorts of complex ways to tackle that problem, because you can’t really do the experiment that would prove it.

The situation with the climate is exactly the same. We can’t do controlled experiments where we change the carbon dioxide level, and we don’t change anything else, to see what effect it has. We can’t change the amount of forestation or levels of methane or aerosols, and not change anything else. But just as epidemiologists and diagnosticians get at a medical question from multiple angles and find a balance of evidence, we do the same for the planet. I think we’ve convincingly shown the planet is affected by our activities, whereas the link between various things and cancer is much more ambiguous. But it’s the same technique.

You’re a scientist, not a policymaker, but in the book you mention the “tragedy of the commons,” the way individuals benefit by using collective resources, to everyone’s long-term detriment. Can we solve climate change, or are we resigned to being unable to take action?

I oscillate between being optimistic and pessimistic. This administration has made very positive statements. But then you look at what people are proposing to do, and how many coalitions we have to get on board to get something changed, it’s easy to throw up your hands and say, “We’re all going to go the way of the Easter Islanders.” Some days I wake up and think that we will, and other days I wake up and think that we won’t.

Which one of those days is it when you hear comments from a scientist like physicist Freeman Dyson, who dismisses climate change as a non-problem?

It surprises me. The guy’s obviously smart, and he’s made a career of thinking against the grain and has come up with good solutions to problems in physics. But he’s had a strong preference for problems that could be solved just by thinking about them. If you look at the kind of things he didn’t go into as a physicist, they required the understanding of complex systems, where there are a bunch of different things going on and it’s not amenable to sitting there with a pencil and paper coming up with a new formula.

You see this a lot. Scientists have preferences for certain kinds of problems. Some people want something straightforward, and others are attracted to the complexity of the real world or the human body and enjoy wrestling out information from something that’s more complex than we can grasp. And he seems to be very much the former.

Dyson told the New York Times, “The climate studies people who work with models always tend to overestimate their models. They tend to believe models are real and forget they are only models.” Well, you’re a climate modeler, so how do you respond to that?

That’s the kind of thing somebody says when they’ve never met a climate modeler. We’re the people who know how the sausage is made. I’m a climate modeler in one of the 20 or so groups whose work goes into the IPCC [Intergovernmental Panel on Climate Change] report. We spend our all our time working out how we can make these things better. We can see the uncertainties and compromises one has to make in order to build a model. We’re traveling the world to find interesting pieces of data, we’re traveling back in time, as it were, back to the last ice age, to find samples to help us see if the models are any good. The idea that climate modelers go around saying, “Our ideas are perfect,” is just nonsense.

What’s a piece of knowledge we’ve gained from climate modeling?

Did you see “The English Patient”? The last scene is in a cave in the Sahara, which obviously used to be an oasis. And it’s true that about 5,000 years ago, the Sahara was much greener and wetter than it is now. Our best guess about why is that the orbit of the earth has changed since then. It used to be warmer in the summertime in the Northern Hemisphere because we were slightly closer to the sun, and now we’re closer to the sun in the wintertime. We can put that in the models. And when we do, the models produce more rain over the Sahara. So our understanding of why the Sahara was greener in the past is pretty good.

But there are still uncertainties among the models about the amount of rain or how far north the rain band goes. And we’re trying to see if there are improvements — if how you deal with clouds, convection, vegetation and land-atmosphere interactions affects the basic underlying results. So far it doesn’t. So that’s a pretty robust result. It’s not that we think the models are perfect. It’s that we have a balance of evidence, and it bolsters the case that we have the right idea of what’s going on.

You quote Thoreau in the book: “The wind that blows is all that anybody knows.” What does that mean to you?

People often interpret climate change in terms of local weather. If there’s a big storm, inevitably somebody will call me up and say, “Is this climate change?” And people will say that the difference in temperature between one summer and the next, in their locality, is larger than what we’re saying about global warming. And that’s true. Global warming comes out when you average these things together, and you look not at the local or regional scales, but the continental and global and hemispheric scales. Then you see the difference.

Weather can give people a look into climate change. New York used to have a lot more snow than it does now. Over a lifetime you can start to see those changes. But people’s memories are poor and the climate change story is best seen in the statistics and in long-terms trends.

It’s a big problem. People can see if the Hudson River or the Gowanus Canal is polluted. Those kinds of environmental problems have local sources and local witnesses. A big conceptual issue that makes climate change difficult to get across is that everything we do is all being mixed into the atmosphere, whether it’s driving in the United States, or a power station in China, or sheep in New Zealand.

What about our sense of geologic time? We have only been here a very short time and yet the planet has gone through billions of years of changes.

Yes, a lot of people look at geology and say, “Well, things have changed in the past, and the planet has survived.” True. But whether the planet survives isn’t only our concern. It’s whether our society survives. Climate change in and of itself is not intrinsically evil. The problem comes because of how we live.

There’s another picture in the book of a house that’s about to collapse in the village of Shishmaref in Alaska. OK, maybe they weren’t so smart, building their house on permafrost that’s going to melt. But it’s not their fault. That entire village has been wiped off the map because the sea ice has gone, leading to erosion on the coast, and it turns out they were building their homes on a pile of sand. And that’s a really good metaphor for what we’re doing here. It turns out we’ve constructed society on a pile of sand, and we’re only just realizing how fragile it is.

At what point did we have enough evidence to say humans are involved in climate change?

People knew in the early 1960s. President Johnson, I think in 1965, discussed in Congress the fact that increasing amounts of carbon dioxide were likely to warm the planet and the temperature might increase by half a degree by the end of the 20th century. So people knew, and everything subsequent has been a question of trying to quantify all the effects. As time has gone on, we’ve accounted for the things contributing to climate change other than carbon dioxide.

You mean like the potential release of trapped methane, which we might not have thought about back then.

It’s not that we wouldn’t have thought about them, but it was difficult to be quantitative. We didn’t have satellite measurements until 1979, so we weren’t able to see the extent of deforestation. We weren’t able to see the extent of changes in use of aerosols and other air pollutants. In the absence of data it’s very difficult to make scientific progress. What we’ve done in the last 30 years is quantify those things. People knew about black carbon a long time ago. But it’s only recently we’ve had the measurements and understanding of the microphysics to quantify the impact. People started thinking about methane as a problem back in 1974. We know a bit more about the chemistry and the sources, but the basic picture hasn’t changed.

How much time do we have to solve the problem, and what should we do?

This notion that we have a certain amount of years to act is a terrible framing. Whatever the situation is, whatever date, there will always be things we can do to make the situation less bad in the future. Our choice is not between a globally warm world or the world that we live in. It makes people think they can just do what they want now, then act in 10 years. The most fundamental thing is that somehow, somewhere, there has to be a price on putting carbon dioxide into the atmosphere.

But because of the multifaceted nature of the problem, because a lot of pollutants have direct impacts on health and the environment as well as the climate, there are a lot of win-win situations. We can help the Chinese reduce their pollutants — which would help them reduce carbon emission and help everyone — or use methane emissions from landfills to run power stations in small communities in the Philippines. People are dying from burning black carbon on their homes in India. We should fix that, as a moral imperative. And in doing so, we can help fix the climate.