We’ve seen that it’s possible to reduce human emissions of green house gases substantially. The technologies are within reach. We need energy efficiency. We need low carbon electricity. And we need electrification of parts of the economy, like automobiles, like home heating, and some industrial processes, to use that clean energy from clean electricity rather than the dirty energy coming from burning fossil fuels. How do we get there? What do we do? Now, one thing must be stressed from the start. Energy is so deeply embedded in our economy, in how we do everything, in industry and transport, in our living, the organization of our cities. We can’t make that transition to low carbon energy overnight. Even if we wanted to, the only way to dramatically reduce greenhouse gas emissions in the short term would be pretty catastrophic. We’d have to close down large parts of our economy. What we’re really looking for, therefore, is a transition over the course of 30 to 40 years. Not a sudden, abrupt end of emissions. But we need to move quickly, because what science tells us is that we have to cut by half or more our total emissions by the mid-century, even as the world economy is expanding dramatically. So, we’ve gotten the hints of what to do. What kinds of policies can be used to get there? Well, let’s consider, once again, the main pillars. Energy efficiency, for example. What kinds of policies can be applied to raise the efficiency of our energy use? One standard kind of policy, which has been quite successful around the world, is to put appliance standards into effect through regulation. And places that put basic standards on automobile, mileage, per gallon, for example, or the energy use in refrigerators and air conditioners, or a shift from a heavy energy using traditional light bulb, the incandescent light bulb, to LEDs and to compact fluorescent light bulbs, can be managed by appliance standards. And quite a lot of energy saving can be accomplished at very, very low cost, or even at net economic savings. Building codes can make a big difference. And building codes are part of the normal policy, framework of any normally run city. And we know that the quality which buildings are built, the insulation materials, the ventilation properties, the placement of the cities, the use of roofs, the internal energy systems whether it’s furnaces and boilers or, or whether it’s electric power sources make a huge difference in the energy efficiency of buildings. New York City, we already have noted it as experienced a major improvement of air quality, as well a major reduction of heavy oil use through regulation of and encouragement eh, through other means and other incentives. Of a shift to much more efficient energy use. Introducing smarter grids and new metering and smart ways that the utility company meters household and then applies pricing systems to encourage households to economize on electricity use, and helps customers to be aware of options on energy efficiency can make a very, very big difference. An even bigger part of the package for in many places will come by shifting from fossil fuels entirely to zero or very low carbon energy sources. The problem so far has been that using coal to produce electricity is often the lowest cost choice. If we don’t take into account the costs of coal to society in the form of air pollution and in the form of climate change. In other words, there’s a basic economic problem that coal has high costs, not reflected in the price of coal in the marketplace. If you buy coal and burn it as a utility, you don’t pay the cost of the carbon dioxide emissions that are going to wreck the planet for everybody else. You’re imposing a cost on others not reflected in the price that you, yourself, bear in using that coal. That’s called an externality, a utility that is using coal to produce electricity is imposing an externality on the rest of the planet. And, by the way, because that carbon dioxide sits in the atmosphere for centuries, it’s imposing an externality even on generations that are not yet born. And they can’t fight back. Can’t sue the, the, the power company. Can’t protest. Can’t call on legislators to tell that power company use a clean energy sources rather than the dirty CO2. And so, we need to correct the market signals if a utility is going to choose a clean energy source like solar power or wind power. Or if it’s going to use a technology that allows it to capture the carbon dioxide that it would otherwise emit, and store that carbon dioxide safely in some geologic reservoir, a technology called carbon capture and storage. No utility is going to chose the higher price variety unless it is forced to bear the true costs of using coal, the cost to health and the cost to climate change. So, economists rightly emphasize the need for corrective pricing. For market signals to tell the truth, to say to the utility, uh-uh, coal is too expensive if you take into account its true social costs. Well, how can market prices be corrected? They can be corrected in a variety of ways. One way is simple, you put a tax on the use of coal, reflecting the CO2 emissions and the health burdens that using that coal will cost. Only companies that capture the CO2 and safely store it wouldn’t have to pay the tax on the coal. And companies that use a non-carbon source of energy, like solar power or wind power, would avoid that tax as well. So, the market signal would say, you can not get away with it any longer, using a socially costly form of energy. Because of that tax, there will be a natural incentive of companies and households and builders everywhere to economize or substitute a way from coal, oil, and gas, and move towards the alternative energy sources that are now less expensive because they don’t bear that tax. There’s another system that can be used, which is that you’re required to have a permit to emit carbon dioxide, and only a few and shrinking number of permits are given out each year. Those permits can trade, a company that has no alternative might buy permits from others. But it’s expensive to buy that permit. It’s like paying a tax, but instead of paying the tax to the government, you may effectively pay that extra cost to whoever is selling you that permit. Could be the government, by the way. So, tradable permits for emissions or taxes on carbon are two ways to correct market prices. Another way to correct market prices is what’s called feed in tariffs. The government says to a utility company or a power generator, we’ll buy electricity from you, but we’ll pay an extra high price if the electricity that you’re bringing into the system is clean. So rather than taxing the dirty stuff, you give an added incentive for power generation coming from wind power or from solar power. These are all ways to tilt the market in the right direction. They’re not the end of the story, unfortunately, because we still need to improve the technologies for using the low carbon energy. The main problem with wind power is that the wind sometimes doesn’t blow. This is an intermittent power supply. The main problem with solar power is too, nighttime and clouds, and so the reliability and predictability of solar power, and the fact that it’s only available certain hours of the day. Mean that solar and wind power and many other kinds of renewable energy need to be stored somehow, stored in batteries, stored in other solutions that are being developed right now. If the problem of storage of intermittent energy sources, like wind and solar power, can be solved at low cost, because the existing solutions are fairly expensive. Then there would be a dramatic, dramatic breakthrough in reducing the overall costs of a low carbon electricity system. All of this means that another part of the policy of decarbonizing the primary energy system is research and development. Government should be investing heavily in new technologies, for instance, in the storage of energy from inter, intermittent power sources. Or in understanding the safety and feasibility of very large scale capture and geologic storage of carbon dioxide. Again, that idea that you continue to use fossil fuels, but you capture the CO2 before it goes into the air, and you put it safely underground. One of my very brilliant colleagues Professor Klaus Lackner, is trying yet another idea which needs a lot of research and development. And that is to capture the CO2 directly, already in the air, through chemical means, and through, then to take the captured CO2 and to store it geologically. It’s another possibility. Can that be done at a low enough cost to be economically feasible? In order to tap these low carbon energy sources, though, there’s one more point that is crucial. Very often we have massive potential for renewable energy, but it’s just not where people live. And then, we need a transmission system to bring that low carbon energy to population centers. And that means that government needs to be involved with long distance transmission of low carbon electricity. That raises many technological issues and many financial issues as well. Here is one very important, I think, a potential breakthrough system that would link the great sunshine of North Africa and the Sahara desert with the energy needs of Europe. This is called DESERTEC. It’s a proposal that engineers put on the table a number of years ago to connect solar power coming mainly from North Africa and the Middle East with the very high energy use in Europe. And the solar power would be taken by long distance electricity transmission lines to Europe. Also shown here in the blue are the wind turbines. And so, this is a system that would integrate wind turbines along the coast, in general, with solar power in the desert and very sunny regions, and enable Europe to shift from a fossil fuel based electricity system to a, nearly zero carbon energy system. It’s a great plan. It requires a lot of research and development. It requires a lot of investment. But it illustrates how to make a big move to decarbonization. Here’s a map of the United States and the main message of this map shows how much potential we have for offshore wind. The northeast coast of the United States from irginia to Maine, for example, is extraordinarily windy. And if wind turbines were put up and down the northeast sea coast, just a bit offshore, there would be enough energy, roughly speaking, to provide all the power needed in the northeast of the United States. How many wind turbines do we have right now off the northeast coast? That would be zero. The permitting hasn’t been given the transmission lines, the decision, which is a public decision that that’s the way we should go, has not been taken. And this is why corrective pricing plays a role, research and development plays a role, but also political leadership. To help say to the American people or to other countries, look, we can go this way, this way, this way, we just can’t stay business as usual. We could use the great wind power on our off-shore coasts. We could use what you’re looking at here, which is a wind field in, South Dakota, where there’s a lot of wind but not too many people. So, we would need long distance transmission lines to bring that wind power from the Dakotas to the big population centers of the United States. We could decide for a massive deployment of solar technologies in the Mojave Desert in the American southwest. Again, we’d have to have transmission lines to bring the power to the big population centers. But we have enough solar energy to provide a very significant fraction of the electricity needs of the United States. Political decision. Not only market forces, but how our land and our coasts are going to be used. What’s the least risk way? What is the safest direction? How are these costs going to be shared? What is the future of nuclear power? People are afraid of it, but they should be also afraid of cold fire power plants. Nuclear power offers one way to a very low carbon economy. Cold fire power plants don’t scare people but should. Because they, more silently, out of the headlines, kill a lot of people and threaten the planet through greenhouse gas buildup. So, what are we to make of these choices of nuclear energy? Of course, this divides scientists, it divides engineers, and it divides the public in a very strong way. My guess is that we will have nuclear power, because many countries, like China and India, and I believe the United States, will continue to deploy nuclear energy into the future. The question is how to make it safe and secure. So for all of these areas of decarbonization or electrification of the energy systems of automobiles, we require lots of public investment, R&D, political decisions, building of infrastructure. In other words, choices that by 2050, we must move to a low carbon energy system. Lest we continue as we’re going and face the calamities that would be implied by that. Now there’s one more problem. I’ve indicated that we have technologies within reach, and they are getting better and better in wind power and solar power, lower costs. But technology is also not standing still for fossil fuels as well. The ability to drill for fossil fuels has also improved markedly over the last 10 years. Some people say that’s great, I say that’s very dangerous. Because it continues to feed an addiction that threatens the planet. If we improve our capacity to tap into these hydrocarbon deposits, we’re also improving our capacity, in quotation marks, to wreck the planet. And there’s a lot of this kind of technological innovation taking place in the hydrocarbon sector. The mining of the Canadian oil sands, a massive deposit of fossil fuels that were really not very accessible technologically, but now are deployable through various advances in the ability to use this kind of heavy oil. And this, again, is being deployed because it’s financially profitable. In large part because the oil companies like the utilities, like the other coal-using industries don’t pay the true social cost of the fossil fuels. Or what is now one of the most contentious technological advances in recent years. The picture shown here of so called horizontal drilling, and hydrofracking or fracking or hydro fracturing of natural gas caught in shale rock. So with this way to put drills down and then turn them every which way, and to blast rock through a high pressured solution, that fractures the rock and releases carbon dioxide. I’m sorry, releases the methane, I should say, and releases, therefore, natural gas that, that can be burned for electricity generation. We’ve expanded, again, the capacity to tap the fossil fuel reserves on the planet. But we have to ask ourselves, are we doing ourselves a favor if we’re slowing down the transition that is increasingly, urgently needed to mitigate climate change. To head off the worst disasters that will be in store if we continue on a business as usual path. We have to make choices. The world has not yet made those choices. Let’s understand that process of decision making better. What will it take for the world to agree?