字幕表 動画を再生する 英語字幕をプリント Chris Anderson: We're having a debate. The debate is over the proposition What the world needs now is nuclear energy" -- true or false? And before we have the debate, I'd like to actually take a show of hands -- on balance, right now, are you for or against this? So those who are "yes," raise your hand. "For." Okay, hands down. Those who are "against," raise your hands. Okay, I'm reading that at about 75-25 in favor at the start. Which means we're going to take a vote at the end and see how that shifts, if at all. So here's the format: They're going to have six minutes each, and then after one little, quick exchange between them, I want two people on each side of this debate in the audience to have 30 seconds to make one short, crisp, pungent, powerful point. So, in favor of the proposition, possibly shockingly, is one of, truly, the founders of the environmental movement, a long-standing TEDster, the founder of the Whole Earth Catalog, someone we all know and love, Stewart Brand. Stewart Brand: Whoa. (Applause) The saying is that with climate, those who know the most are the most worried. With nuclear, those who know the most are the least worried. A classic example is James Hansen, a NASA climatologist pushing for 350 parts per million carbon dioxide in the atmosphere. He came out with a wonderful book recently （Storms of My Grandchildren） called "Storms of My Grandchildren." And Hansen is hard over for nuclear power, as are most climatologists who are engaging this issue seriously. This is the design situation: a planet that is facing climate change and is now half urban. Look at the client base for this. Five out of six of us live in the developing world. We are moving to cities. We are moving up in the world. And we are educating our kids, having fewer kids, basically good news all around. But we move to cities, toward the bright lights, and one of the things that is there that we want, besides jobs, is electricity. And if it isn't easily gotten, we'll go ahead and steal it. This is one of the most desired things by poor people all over the world, in the cities and in the countryside. Electricity for cities, at its best, is what's called baseload electricity. That's where it is on all the time. And so far there are only three major sources of that -- coal and gas, hydro-electric, which in most places is maxed-out -- and nuclear. I would love to have something in the fourth place here, but in terms of constant, clean, scalable energy, solar and wind and the other renewables aren't there yet because they're inconstant. Nuclear is and has been for 40 years. Now, from an environmental standpoint, the main thing you want to look at is what happens to the waste from nuclear and from coal, the two major sources of electricity. If all of your electricity in your lifetime came from nuclear, the waste from that lifetime of electricity would go in a Coke can -- a pretty heavy Coke can, about two pounds. But one day of coal adds up to one hell of a lot of carbon dioxide in a normal one-gigawatt coal-fired plant. Then what happens to the waste? The nuclear waste typically goes into a dry cask storage out back of the parking lot at the reactor site because most places don't have underground storage yet. It's just as well, because it can stay where it is. While the carbon dioxide, vast quantities of it, gigatons, goes into the atmosphere where we can't get it back, yet, and where it is causing the problems that we're most concerned about. So when you add up the greenhouse gases in the lifetime of these various energy sources, nuclear is down there with wind and hydro, below solar and way below, obviously, all the fossil fuels. Wind is wonderful; I love wind. I love being around these big wind generators. But one of the things we're discovering is that wind, like solar, is an actually relatively dilute source of energy. And so it takes a very large footprint on the land, a very large footprint in terms of materials, five to 10 times what you'd use for nuclear, and typically to get one gigawatt of electricity is on the order of 250 sq. mi. of wind farm. In places like Denmark and Germany, they've maxed out on wind already. They've run out of good sites. The power lines are getting overloaded. And you peak out. Likewise, with solar, especially here in California, we're discovering that the 80 solar farm schemes that are going forward want to basically bulldoze 1,000 sq. mi. of southern California desert. Well, as an environmentalist, we would rather that didn't happen. It's okay on frapped-out agricultural land. Solar's wonderful on rooftops. But out in the landscape, one gigawatt is on the order of 50 sq. mi. of bulldozed desert. When you add all these things up -- Saul Griffith did the numbers and figured out what it would take to get 13 clean terawatts of energy from wind, solar and biofuels, and that area would be roughly the size the United States, an area he refers to as "Renewistan." A guy who's added all this up very well is David Mackay, a physicist in England, and in his wonderful book, "Sustainable Energy," among other things, he says, "I'm not trying to be pro-nuclear. I'm just pro-arithmetic." (Laughter) In terms of weapons, the best disarmament tool so far is nuclear energy. We have been taking down the Russian warheads, turning it into electricity. 10 percent of American electricity comes from decommissioned warheads. We haven't even started the American stockpile. I think of most interest to a TED audience would be the new generation of reactors that are very small, down around 10 to 125 megawatts. This is one from Toshiba. Here's one that the Russians are already building that floats on a barge. And that would be very interesting in the developing world. Typically, these things are put in the ground. They're referred to as nuclear batteries. They're incredibly safe, weapons proliferation-proof and all the rest of it. Here is a commercial version from New Mexico called the Hyperion, and another one from Oregon called NuScale. Babcock & Wilcox that make nuclear reactors ... here's an integral fast reactor. Thorium reactor that Nathan Myhrvold's involved in. The governments of the world are going to have to decide that coal needs to be made expensive, and these will go ahead. And here's the future. (Applause) CA: Okay. Okay. (Applause) So arguing against, a man who's been at the nitty-gritty heart of the energy debate and the climate change debate for years. In 2000, he discovered that soot was probably the second leading cause of global warming, after CO2. His team have been making detailed calculations of the relative impacts of different energy sources. His first time at TED, possibly a disadvantage -- we shall see -- from Stanford, Professor Mark Jacobson. Good luck. Mark Jacobson: Thank you. (Applause) So my premise here is that nuclear energy puts out more carbon dioxide, puts out more air pollutants, enhances mortality more and takes longer to put up than real renewable energy systems, namely wind, solar, geothermal power, hydro-tidal wave power. And it also enhances nuclear weapons proliferation. So let's just start by looking at the CO2 emissions from the life cycle. CO2e emissions are equivalent emissions of all the greenhouse gases and particles that cause warming, and converted to CO2. And if you look, wind and concentrated solar have the lowest CO2 emissions, if you look at the graph. Nuclear -- there are two bars here. One is a low estimate, and one is a high estimate. The low estimate is the nuclear energy industry estimate of nuclear. The high is the average of 103 scientific, peer-reviewed studies. And this is just the CO2 from the life cycle. If we look at the delays, it takes between 10 and 19 years to put up a nuclear power plant from planning to operation. This includes about three and a half to six years for a site permit. and another two and a half to four years for a construction permit and issue, and then four to nine years for actual construction. And in China, right now, they're putting up five gigawatts of nuclear. And the average, just for the construction time of these, is 7.1 years on top of any planning times. While you're waiting around for your nuclear, you have to run the regular electric power grid, which is mostly coal in the United States and around the world. And the chart here shows the difference between the emissions from the regular grid, resulting if you use nuclear, or anything else, versus wind, CSP or photovoltaics. Wind takes about two to five years on average, same as concentrated solar and photovoltaics. So the difference is the opportunity cost of using nuclear versus wind, or something else. So if you add these two together, alone, you can see a separation that nuclear puts out at least nine to 17 times more CO2 equivalent emissions than wind energy. And this doesn't even account for the footprint on the ground. If you look at the air pollution health effects, this is the number of deaths per year in 2020 just from vehicle exhaust. Let's say we converted all the vehicles in the United States to battery electric vehicles, hydrogen fuel cell vehicles or flex fuel vehicles run on E85. Well, right now in the United States, 50 to 100,000 people die per year from air pollution, and vehicles are about 25,000 of those. In 2020, the number will go down to 15,000 due to improvements. And so, on the right, you see gasoline emissions, the death rates of 2020.