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Well, in a week in which the pope has exhorted us not to be sourpusses, we're going to hear from a pessimist about global warming, and also an optimist. At issue is the broad scientific consensus that to keep global warming in check, we need to try to phase out 80 percent of all oil, coal and natural gas by mid-century. But is that possible? NPR's Richard Harris talked to an economist and a technologist who takes different sides.
RICHARD HARRIS, BYLINE: The University of California at Berkeley is home to hundreds of scientists, economists, engineers and students who live and breathe climate change. I talked to two of them, on opposite ends of the optimism spectrum, to see whether it's even possible to phase out most U.S. carbon emissions by the middle of this century.
CATHERINE WOLFRAM: It's going to be very tough.
HARRIS: That's Catherine Wolfram, an economics professor and co-director of the Energy Institute at Berkeley's Haas Business School. And she's skeptical in part because every roadmap to clean energy assumes that we will make huge improvements in how efficiently we use energy. Advocates have been arguing for decades that this is an enormous opportunity to save money and energy at the same time. It's as though there's cash lying on the sidewalk, just waiting to be picked up.
WOLFRAM: Those opportunities have been around for a while and people aren't doing it, so there's a real question about why they aren't. And one of the fundamental questions that raises is whether there really are $20 bills lying on the sidewalk.
HARRIS: She has academic research to back up that skepticism, but she also turns to her own life for an example.
WOLFRAM: We had a company come to our house and make a bunch of recommendations to make our house more energy efficient. And one of them involved blowing insulation into our walls and drilling holes every three feet on our walls.
HARRIS: Once Wolfram realized how much it would cost, not just for the insulation, but to patch and repaint all of her walls, she concluded that it wasn't worth it for the modest savings she'd see on her energy bills. No sale. Wolfram's also leery of the cost of switching to renewable sources of energy like wind and solar. Prices will have to rise substantially, if you make all the infrastructure changes that would be required to make these on-again-off-again energy sources the backbone of our energy system.
WOLFRAM: Given the technologies we have today and given the economics of the current technologies, it is a really hard problem. I hate to say it, but may be an impossible problem. I think it's a problem that needs a technological breakthrough.
HARRIS: Nobody can predict a breakthrough, so when an economist crunches the numbers, things look pretty grim.
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HARRIS: But the world doesn't look so gloomy to her colleague, Daniel Kammen. He's a professor of energy and nuclear engineering, ensconced in a program that's dreaming of a low-carbon world.
DANIEL KAMMEN: Well, I'm writing a book right now called "Energizing the Optimist." So, I'd better be in the optimist category, and I think I am. In fact, maybe I'm so much in the category that a couple of my students say their goal is to rein in my optimism.
HARRIS: Kammen thinks advances in technology on the horizon can push the United States rapidly away from fossil fuels. If we put a price on the environmental damage caused by carbon dioxide, he says clean energy like solar would become comparatively cheaper. And that would trigger a whole new relationship between people and energy. Homeowners become producers, not simply consumers, of power. People would have a powerful reason to install solar panels, store some of that energy in the batteries in their electric cars, and even send pulses of it back to the electric grid.
KAMMEN: There will be an opportunity to sell that power back to the utility, making money on the deal. And people will think of their cars and their homes as not devices that simply suck up money in the form of energy, but generate it and put it back in the system and make money.
HARRIS: The grid would have to be reconfigured to handle all those scattered energy sources, but Kammen says if there's money to be made, innovation will surely follow.
KAMMEN: So, I don't think the 80 percent reduction goal by 2050, which sounds like radical surgery - it sounds like a new industrial revolution - is going to be that hard. I would even say we could do it in a decade or two if we were properly motivated.
HARRIS: The real question in his mind is not whether we could achieve this in the United States but whether this could happen in the rest of the world, which is in fact where most of the future carbon emissions will originate.
KAMMEN: Things do look grim. The growth rate in population, affluence and energy use in many developing countries - China, India, Brazil, Indonesia - looks really daunting.
HARRIS: But if the United States can invent its way out of climate change, he's optimistic we can also invent ways to spread that solution around the world. Richard Harris, NPR News.