I’m going to start right into the talk. Very briefly the outline of the talk is to first show that technical innovations based on science have truly changed the world. That if necessity is the mother of all inventions, then we have the "mother of all necessities", namely how to deal with climate change. And finally, science and innovation again is needed to transform the world as it has in the past. So let me remind you very quickly: the invention of the steam engine, the improvement of the steam engine really issued in a new era. And here you see an iconic warship Temeraire being towed by a steam belching tug boat to its final berth where it’s going to be chopped up for scrap. It’s really the setting of an era and the opening of a new age. There are other transformative technologies. For example in an institution I worked at for 9 years, AT&T Bell Laboratories, they were developing vacuum tubes in the ‘20s and ‘30s and ‘40s because they needed vacuum tubes for long distance communication. For those of you in the audience who are under the age of 60: That’s what a vacuum tube looks like. But these things burned out. They were heated up to red hot and eventually they burned out after 1, 2, 3, 4 years. And this is not good for transcontinental undersea cables. So they wanted to develop a solid state vacuum tube. And they set out on a programme that lasted 9, 10 years; a concerted programme to say let’s use our understanding of quantum mechanics and see if we can develop a solid state vacuum tube. The inventors Shockley, Brattain, Bardeen were awarded the Nobel Prize for this work. That was the first transistor. It looks pretty ugly, something only a mother could love. (laughter) However, they knew it would lead to other things. This is the first integrated circuit - even uglier - with only 4 components. And yet over a period of several decades, constant improvements, constant innovation went from a 4-device circuit like this to devices that have 10 billion or more transistors in a single chip, perhaps a centimetre square. In addition to that innovations in optical fibres, lasers, innovations in wireless technology really transformed the world. So out of this I want to emphasise, as you’ve heard before, that fundamental research is the foundation for the development of this technology. However, mission-driven R&D was also necessary, and it occurred over several decades. So let me now explain innovations in agriculture. In 1898 Sir William Crookes, who invented the Crookes tube, a precursor to actually an electron tube, delivers an inaugural address as president of the BritishAassociation for the Advancement of Science. But he doesn’t deliver a normal ordinary address, thank you for being here, I’m so glad to be part of this, blah; he gets up there and opens the lecture by saying, 'England and all civilised countries are in deadly peril.' And he explains that the artificial fertilisers that were being imported from Chile, Chilean saltpetre, based on the rate of mining that saltpetre and shipping it to Europe, would be depleted within a few decades. That would no longer sustain the soils of Europe, and he predicted mass starvation. However, he said, 'It is the chemist who must come to the rescue ... before we’re in the actual grip of actual death, the chemist will step in and postpone the day of famine.' - I thought that would go well with the Lindau conference and chemists. This set off an incredible race, believe it or not. Starting with Wilhelm Ostwald, the chemist in those days, who thought he developed a way of taking nitrogen and making it into ammonia. And that was the first step in making nitrogen-based fertiliser. And indeed he convinced the German company BASF to hire a chemist to prove that what he saw glimmers of in the laboratory was indeed true. And it turned out not to be true. And it was this man, Fritz Haber, who succeeded and got the Nobel Prize in 1918, collaborating with this man, Carl Bosch, who was hired by Ostwald to see if his original idea worked. In fact, I should say Haber was driven also by a competition. He wasn’t really going to do this but he was driven by a very deep conversation with another chemist, Nernst. Now this development, the synthesis of ammonia, was deemed so important they gave a Nobel Prize to Haber in 1918. They gave a second one to Bosch in 1931. And indeed when Gerhard Ertl got his Nobel Prize for understanding catalysis it was mentioned in the Nobel Prize announcement, I should also say that Ostwald and Nernst also got Nobel Prizes in chemistry. So sometimes you can get a Nobel Prize and lose a scientific race. Anyway, the Haber-Bosch process enabled the world to feed itself, even though the population doubled. But the population more than doubled, it soon tripled. And in the late 1960s a Stanford professor, Paul Ehrlich said that, in a popular book, The Population Bomb. And he wrote, ‘The battle to feed all of humanity is over. In the 1970s and 1980s despite crash programmes hundreds of millions of people will starve to death – in spite of these crash programmes.' And so the question is, what actually happened? What happened actually was quite not what he expected. that had very, very thick kernels and very short stems, because the kernels were so thick and heavy that with normal wheat they would collapse under its own weight. And these strains of wheat could actually withstand artificial fertilisers and a sudden growth spurt. And so this had a profound impact on agriculture. And to show you how profound an impact: When we go from 1960 to 2005, the population more than doubled, 3 billion to 6.5 billion people. This was the grain production in the world. This was the land put under agricultural cultivation for grains, for human feed. And so the population doubled and yet we'd use the same amount of land. But we now know even despite this incredible advance that we really need a second green revolution in order to go further. We might have to go to perennial crops, much less tillage or no tillage, drought resistance for sure, and perhaps nitrogen fixation. Now, you’re probably thinking, well there’s technological fixes. We’re now 7 billion people. By 2025 we estimate to grow to 8 billion people, by 2050 9 billion people. And so what’s the point? We get a technological fix. Our population grows. We get into another mess. Where do we go from here? Ah, there’s light at the end of the tunnel. This is the projection of the population growth depending on 3 estimated fertility rates around the world. And what it really is saying is the following: By the end of this century it may be probable or possible that the population will actually peak and decline. Why is this? It’s because we’ve been noticing over the last 2 decades across all cultures, all religions, everything: The richer you get, the more you go into middle class life, you have fewer children. There may be many reasons for this: Education of women, infant mortality goes away or is greatly reduced, late night TV - choose your favourite.(laughter) But in any case for the first time we see that if you get past this century, there is light at the end of the tunnel. But you could possibly get to a sustainable world, because the population will stabilise, and indeed it may even shrink. Which puts us into another paradigm because in a growing population it’s a sort of a mild Ponzi scheme: more young people taking care of fewer old people - good. You can be somewhat inefficient. Fewer younger people taking care of older people, harder. So we have to think about that again with sustainability. So let’s talk about this necessity. The reason why I chose to leave Stanford to become a bureaucrat, shudder (laugh), and even to go to Washington, is the following. These are direct temperature measurements of the land surface of the Earth. These are several groups. The latest group went in with the eye that all the groups did the wrong thing. There was data selection; they didn’t analyse the data right. But in the end they found that indeed they may have analysed the data right. So this is 1800 to 2010, the mean average surface temperature. And you notice over this time period a few things. First, we don’t understand this plateau, or possibly even dipping. There’s another recent plateau that many people made a lot of noise about. And so we cannot predict why there are these plateaus and perhaps dips. We certainly can predict the little bumps. But we can see over a 200 year period that the temperature seems to have been rising. And in that period over the last 30 or so years, maybe ¾ of the temperature increase has occurred. And so what are the consequences of this? Well, the sea level is rising. It has gone in past millennia with hardly any change in average sea level height, it's now going above 3 millimetres per year. And there’s been a lot of toing and froing about what’s this due to? Are the glaciers really melting? And the most compelling evidence is now coming from satellite measurements. This is a GRACE satellite measurement. This is an artist’s conception of 2 satellites co-orbiting the earth, where the distance between the 2 satellites is very precisely measured. And little changes in gravity perturb these orbits and hence the distance between them. And by monitoring the distance between these 2 satellites you can actually measure the local changes in gravitational traction of the earth. And what they do when they fly over Greenland is they find: yes indeed, the ice sheet in Greenland is declining. And this is the period 2002 to 2012. The sensitivity is so good you can see summer, winter, summer, winter. But it’s not only declining, it's accelerating. It's real. They can monitor parts of Antarctica. They can monitor the Himalayan plateau. But they found the Himalayan plateau is not yet declining, right. And in parts of Antarctica it is and other parts it’s increasing. But the point here is that improved sensitivity, improved measurements, will really tell you what’s going on. Now there have been heat waves. There was a heat wave in Europe in 2003; over 50,000 people died in that single heat wave. There was a heat wave in Russia in 2010; 10 to 15,000 people died in that heat wave. But you say, well you can’t really tell a single event, whether this is a real change. It just could be an extreme single event. And so that is a valid point. So this is data from a reinsurance company - a reinsurance company is a company that insures insurance companies. Now what does that mean? If you’re an insurance company and there’s a massive flood, a massive earthquake, a massive hurricane, you don’t have the assets to pay the premiums. So you take out insurance to ensure that you can actually pay out the premiums. And so re-insurance companies are concerned about major weather events and other catastrophes. So this is Munich Re, a reinsurance company. The brown is earthquakes over a 30 year period: 1980 to 2010 and beginning of 2011. The green are meteorological events, storms. The blue are floods. The yellow are extreme heat waves, cold waves, droughts, forest fires. And this is just the number in the United States, not losses, just the number. And the United States is a well-reported country - we have lots of monitors. But what you see is the number of events seems to be climbing. In that same period, that 30 year period, with a temperature climb. In terms of insurance losses, well there were a lot. This dark blue is insured losses, the light blue is uninsured losses. If you look at this dotted line, the trend line: in the United States we went from $40 billion a year to over $170 billion a year. So this is beginning to be real money - even by Washington standards. So anyway, this is happening. And what I feel very strongly about this is... I feel we don’t understand a lot of the climate miles. We will be able to understand the climate miles in the current years and decades. But I prefer to take a very epidemiological point of view towards climate change. The way we took that view when there was a suspicion that cancer was caused by smoking – not all cancers but if you smoked you had a higher probability of cancer. And after 10 or 20 years it became very clear smoking increased the probability of getting cancer. Even though we did not have a biological molecular view of how it happened. We may not have a detailed climate model view of what’s happening, but we know something is happening if it’s correlated with the increasing temperature. So now you can say and you might have heard that the temperature has increased in previous eras, epochs. This is a long time, this right here is the present time and you’re going backward in time, this is 600,000 years ago. This is a proxy for a measurement of temperature. It is actually the amount of deuterium you’ll find in ice core samples in Greenland and in Antarctica. Why are you measuring deuterium, the ratio of deuterium to hydrogen? Deuterium weighs more than hydrogen, therefore it evaporates less quickly. And so if it evaporates and is transported over Antarctica and it comes down in snow, you’ll have depleted deuterium. And so by using this proxy, it’s a rough measure of temperature. So here we are in a very warm period relative to the last 600,000 years. You go back, this is in the ice ages. And you go back to here where you’re in another warm period with slightly higher temperatures. It’s estimated it's about 2 degrees centigrade average higher. And it's estimated, based on other evidence that I don’t have time go to into, that the sea level was at least 6.6 metres higher in this little warm period. You also can measure the amount of carbon dioxide in the Earth. You can measure, that’s been trapped in these glaciers, the amount of nitrogen oxide, methane. And you notice at this very tail endpiece, you see these very sharp vertical lines – that’s the change in greenhouse gases in the last 200 years. And I want you to notice that we are off the scale of what has happened in the last 600,000 years. Indeed, we’re off the scale of what happened in the last 2 million years. And so that’s why there’s nervousness. Because when you have greenhouse gases, you’re trapping more heat - you don’t really know what’s going to happen. The technique is very much like geology. In this stratified rock that you look at in the geological record you have stratified layers of ice. And you go deeper and deeper into the ice cores. And then you have a time record of what’s been deposited in terms of these isotopic elements. And that’s how we get the data. There’s a lot of cross correlation with other methods to validate that this indeed is giving you the right answer. The carbon dioxide has increased, but it might have been due to natural causes. And what’s the signature that it has to do with humans? Well, the first suspicion is that this is the amount of CO2, going back a few thousand years, 5,000 years, and this is the start of the industrial revolution. So you say, um that’s a little suspicious. Also this is the population increase of the world, streaming up, starting about at the industrial revolution. But it’s just more than that. Because we have a rough idea of how much fossil fuel we put up since the start of the industrial revolution. And the numbers roughly match. So this CO2 by counting seems to be consistent with the industrial revolution. But it’s even better than that. You can look at isotopes of carbon. Carbon 14 is produced in the upper atmosphere due to cosmic rays. And then this carbon 14, which is radioactive, diffuses down into the lower biosphere, it gets mixed with all things living or inorganic. You and I have carbon 14 in our bodies. When we die - imagine you were put in a very exclusively good mausoleum, good for 10 million years. What will happen? Well, carbon 14 has a half-life of 5,700 years. When you exhume the body a million years later, it has no more carbon 14; you just got carbon 12. Now you take us and put us in a power plant. And up goes our carbon, recycled into the atmosphere. And what happens is, if there’s a significant amount of fossil fuel release, you’re adding carbon 12, not carbon 14 – remember that carbon 14 is made in the upper atmosphere. And at a steady state you would just have a steady ratio of carbon 14. So here’s the ratio of carbon 14 in the green, going down, down, down as the amount of carbon dioxide goes up, up, up. Wait a minute: data runs out in 1950. What happened in 1950? Well, what happened in the 1950s is, the first thing I’d say, it’s followed soon by Russia, the Soviet Union, were doing atmospheric testing of hydrogen bombs. Those things made a lot of carbon 14. And so the carbon 14 went sky rocketing up. And this is in the northern hemisphere, in the light green. And this is fascinating: those oscillations are the mixing of the upper stratosphere with the lower atmosphere, the yearly mixing. This time delay is the time it takes the northern hemisphere to mix with the southern hemisphere and so you have a measure of that. You see the ocean mixing, picking up of the radioactive carbon made by hydrogen bombs, first in the northern hemisphere, then in the southern hemisphere. And things seem to be going back to an equilibrium. However, it’s going down too fast. And if you look at the numbers it turns out, within 25% uncertainty - that’s the carbon 14 – that dilution of carbon 14 is consistent with the fossil fuel we burned. So it has got finger prints on it, that indeed seem to be due to humans. It’s been at least fossilised carbon that has been exhumed. Alright let’s talk briefly about science and innovation. This is why I became a director of a national lab and became Secretary of Energy, because I believe that science and technology can give us better solutions. So I’m going to very briefly talk about energy efficiency and clean energy sources. Refrigerators are wonderful, they keep your food cold. But as features got incorporated into refrigerators, for example frost free where you blow hot air into a refrigerator so you don’t have frozen ice in your freezer section, that means you had to re-cool it and your efficiency was plunging. So in 1975, starting with the State of California, we introduced refrigerator standards that insisted that the refrigerators that could be sold had to be above a certain efficiency. And of course the efficiency went up. Compared to 1975 today’s refrigerators are about 22% bigger - the average American refrigerator is enormous, it's 22 cubic feet - but it costs 3 times less to own and operate than in 1975. By the way, the size of American refrigerators is beginning to plateau. Not because of the size of the American appetite - it has to do with the size of the kitchen door. But when you’re improving the efficiency of refrigerators it was always assumed that refrigerators would then cost more. And first cost in the United States matter. Maybe you couldn’t afford the extra couple of hundred dollars to buy an efficient refrigerator. So I and a team of people said, well let’s look at the data, is that really true? And so here are refrigerators: before standards, the first Californian standards, second Californian standards, third Californian standards, federal standards - there are 6 of them in here. This is when standards start. This is the purchase price and the cost of operation. This is on a log graph. So that if you didn’t have standards you might assume that perhaps the cost of operation would be here, about $4,000 or $4,500; instead it's $1,500. A big deal. This is the purchase price of the refrigerator. It didn’t have an influence on the purchase price. We looked at other appliances. Clothes washers - ooops, standards made the purchase price go down. What’s happening? And indeed it’s not only clothes washers; in room air conditioners, in central air conditioners, the same thing happened. The introduction of standards made the first price go down. Maybe because it forced manufacturers to retool and they got more efficient. We don’t know the real reason, we’re data collectors, we’re physicists. But in any case, let me go to something else. Electric vehicles. Our goal is to produce an electric vehicle by 2022 that would cost... a 4 or 5 passenger car that would cost about $20,000/$25,000. And we call this 'EV Everywhere'. We got the president to announce this. So this was a good coup for us. You could say, well, you know electric cars, who wants to buy electric car, not a very exciting tiny thing. But let me tell you, I have a friend who owns one of these babies. This is a Tesla S - a very, very exciting car. You know - I don’t know why, who wants to go to 0-60 in 4½ seconds, but that’s what it does. And it goes 300 miles on a single charge. And if you look on the inside, that big thing in there is an LED display touch screen that is like a humongous iPhone. And you can touch it and it’s as intuitive as an iPhone. My friend, I’ve ridden in this a couple of times, and he just raves about it. He loves this car. But this car costs nearly $80,000. And so you’ve got to get the price of the car down. The performance is there, it has more luggage space than a normal car; it has a front and a back trunk, because the battery is underneath. So in 2008 the cost of manufacturing batteries was about $1,000 a kilowatt hour. And 2012 it was cut in half. Tesla claims its cost of its batteries is about $300 a kilowatt hour. Our target in the Department of Energy was: by 2022, can you get this down to maybe $150 a kilowatt hour? But it’s not only the cost. You also have to have durability; it’s got to last 8,000, 10,000, moderately deep discharges. It has to be temperature tolerant so that it can work at high temperatures, it can work at low temperatures. But if you have these qualities, at this cost or even somewhere between this cost and that cost, you have your $25,000 car that can go 300 miles, maybe 0 to 60 in 7 seconds. But that’s what we’re trying to push. Let me talk about clean energy sources. The first thing, I’m going to focus on renewables. You might ask, is there enough energy heating the Earth to even come close? And the answer is 'maybe'. There is 174 PW - peta is 10^12 - of energy heating the earth. A lot of it gets reflected back by clouds, by the atmosphere, reflected by land, but 89 petawatts are absorbed. How does that compare to what we use? Well, this is how much in kilowatt hours we use a year. This is how much is absorbed a year. And this is how much we use. So we have... it's 2 times 10^-4 of what is absorbed. So there is a little room to improve what we can do. And so it’s not clear whether - of course we can’t capture anything close to even 1/10th of this energy – but can we capture 1/10th of 1% of the energy is the issue. Now let me talk about transportation fuel. Batteries - 300 miles. Well, you can’t go 500 miles, there’s limitations in charging, but that’s actually improving dramatically. But let me tell you how good liquid transportation fuel is. And I don’t see in the foreseeable future a battery-powered plane, a commercially battery-powered plane. If you look over energy density - the amount of energy per volume, amount of energy per weight – what you find up near the top are these chemical fuels: diesel fuel, gasoline, body fat. Kerosene, ethanol - much lower energy density. Methanol, still much lower energy density. Where are lithium ion batteries? They’re so close to zero it’s hard to see. So the lithium ion batteries of today are 1½ orders of magnitude worse. But they don’t need to get an order of magnitude better. They can get a factor of 4 better. And now you’re in 300/400 miles, because the motor is so much smaller, the motor is so much more efficient. Ok so it doesn’t have this big a gap. But again for airplanes you need this stuff. I just want to take a little aside and, since I’m a professor and you’re students, I’m going to give you a quiz. What does a Boeing 777 have in common with a Bar-tailed Godwit? What’s a Bar-tailed Godwit? It’s a bird; it’s a bird about this big. This is a strange bird: it spends, 'summers' in Alaska and then it decides to fly to New Zealand, you know, in the seasonal change. Most of the time it does a fuelling stop in China but some of them actually fly nonstop from Alaska to New Zealand. Once they start flying they’re on more or less autopilot. No food, no nothing. And so when this bird takes off and when a 777 takes off, they can both fly non-stop for 11,000 kilometres. They both take off with half of their weight in fuel. And when you land: one skinny bird. But it is that high energy density of body fat, as long as the airplane... which is comparable to airplane fuel, which makes a body fat so good - unless you don’t want body fat. I’m going to skip this on terpene, because I’m running out. It has to do with unusual biofuels. It turns out that pine trees create a compound that is very, very close in oxidation states of carbon to gasoline – much better than methane, much better than carbohydrates. And so what you have here is an idea that we’re funding through an innovative funding agency RPE, which actually taps these pine trees the way you tap it for maple sugar, and you genetically modify it to get up the production of this terpene up by an order of magnitude, and we’re going to pilot this. And perhaps by just having trees already grown for lumber, you can tap them and continuously extract a compound that is very, very close to a fuel that you would want to use in an airplane or a car. And so just as a way of using land in a novel way that perhaps would work. We also are working very hard on transmission systems and energy storage. These transmission systems especially need new electronics that can up the voltage very much more efficiently, so you can get the voltage up to a million volts DC. You can send that DC power over lines: 1,000 miles with 5% loss in energy already has happened in China. So that means you can port renewable energy over 1,000’s of miles without that much loss in energy. But it costs a lot of money to get DC line voltages up and down. And so we want to develop electronics, higher frequency electronics. So instead of working at 50 hertz or 60 hertz, you work at 50 or 60 kilohertz. And you think this is a dream, but in actual fact in the RPE’s last conference a small company brought in a prototype of this converter that replaced a 70,000 pound transformer. He could pick it up by himself, in the trunk of a car, put it down in a suitcase, and it does the same thing. And so if this becomes commercially available this will be a very big deal. Also batteries. Solar energy. Solar energy has dramatically come down from $8 for a fully installed utility scale in 2004 to less than $4 in 2010. The Department of Energy goal was to get it to $1 a watt - a watt is a certain illumination power – where you think the solar module, instead of being $1.70 in 2004 could it be 40 cents? Now that is not completely a pipe dream; right now the spot price is 70 cents. And so it turns out that all the other things in the solar thing are becoming the real issue. The solar module itself, and now soon the electronics, will be less than half the cost of solar farms. But there’s still a lot of technological headroom. Normally what you do is you take very purified silicon, you cast it in ingot, you saw it up into bricks and then take a very fine diamond string saw and chop it into wafers maybe .15 millimetres thick. And you dope it and make it into a solar cell. RPE and the Department of Energy are funding an innovative approach to a new start-up company. And their approach is the following: you take a strawberry, you dip it into white chocolate, you pull it out and you can control the amount of white chocolate on the strawberry. Similarly you take a carbon substrate, you dip it in molten silicon, you hold it up, it dribbles off. And maybe instead of 150 microns you can make a 30 micron piece of silicon. Why do you want to do that? Half the cost of the solar module is the cost of silicon, and this stuff is non-recoverable. And so then you drop... at first glance you could drop the cost by ¼. And they’re getting solar conversion efficiencies now comparable with this method. So the quality of these cells is actually comparable. So that would be exciting. Here is another thing: if you live in Germany the cost of installing on your roof top solar panels is about $2.50 a watt. In the United States it costs $6 a watt. What’s going on here? Is it the cost of labour? I think not, it’s the cost of other things, especially other, what we call soft costs: licencing costs, inspection costs, things like that. And so, 'Unlike physics, where we can fundamentally figure out the upper limit for efficiency of solar cells, there’s no such upper limit to bureaucracy.' And so we have now been focusing more on actually getting the soft costs of bureaucracy down in various towns and cities across the United States. I’m going to skip this, but there’s a thing coming along which says: With very inexpensive energy storage in solar, you can put this stuff on your roof top, you can put a battery in your home, and all of a sudden you can be 80% off the grid. And this could be very disruptive. In fact, it could be so disruptive that utility companies will lose their customers. And so they are beginning to get nervous and are beginning to fight solar installations, at least in the United States. And so here’s a solution. Let the utility companies own the equipment. They maintain the equipment, they install the equipment, the module and the battery. And this is not new, that’s the way the old telephone system worked: they owned the phone; they took care of the phone, you just got phone service. So you just get electricity service for less than the cost of normal electricity. Why can it be less? It’s because... well, what do you get? You get a battery in your home that makes you immune to blackouts, for at least a few days. What does the company get? The company gets a battery in your home, which is away from the elements. So it’s a much more benign environment. And they would love to distribute batteries at the end of their distribution systems. And they get standardised equipment. And they own it. So they’re a piece of the investment, which is a growth industry. So in these things we started in the Department of Energy - they are very, very ambitious. And I tell you, as I told my students and postdocs over the last 25 years: but in setting our aim too low and achieving our mark.’ That was said by Michelangelo. So, you students, remember that. Fail, fail fast, move on - but set your aim high. Now you know as I was in politics and there were some parts of politics I really didn’t like. There was very unfair press coverage, and sometimes you get slammed. And then 7 days, 6 days after I announced I was stepping down from Secretary of Energy, I see this newspaper article, where... (laughter, applause) Let me read you some of the lines. Energy Secretary Steven Chu awoke Thursday morning to find himself sleeping next to a giant solar panel he met the previous evening - didn’t even remember the manufacturer’s name. According to sources, Chu’s encounter with the crystalline-silicon solar receptor was his most regrettable dalliance since 2009, when an extended fling with a 90-foot wind turbine nearly ended his marriage.’ I walked into work that morning. My public affairs person says, we’ve got to respond to this. So I said ok. Rolled up my sleeves, licking my chops, and out we came with a press release about noon. with the allegations made in this week’s edition of the Onion. While I’m not going to confirm or deny the charges specifically, I will say that clean renewable solar power is a growing source of U.S. jobs and is becoming more and more affordable; so it’s no surprise that lots of Americans are falling in love with solar.’ And they would not let me put in ‘despite your sexual preferences’. So you’re looking very nervous. Rather than ask for permission I’m going to ask for forgiveness. I think we have a moral responsibility to deal with this climate change issue, because it’s going to affect the most innocent victims of society: it’s the poorest people of the world, which contributed nothing to this, and those yet to be born. And there is an ancient Native American saying that says And I really need his forgiveness, but I’m not going to look at him, because I’m going to show a little movie. This is a movie of Voyager 1 that’s now finally leaving the outer reaches of the solar wind. But it was designed to look at the planets and fly by the planets; and it was launched in the 1970s. So when it was leaving the orbit of Pluto, Carl Sagan asked the NASA people, Turn the cameras backward and see if you can find Earth. And what does Earth look like at a distance, the distance of Pluto?' And this is what he found. From this distance the earth might not seem of any particular interest. But for us it’s different. Consider again that dot. That’s here. That’s home. That’s us. On it is everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilisation, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species lived there The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors, so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner – how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely spec in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves. The Earth is the only world known so far to harbour life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot - the only home we’ve ever known. Thank you.