NANOTECHNOLOGY AND THE NEXT 50 YEARS

R. E. Smalley Presentation
University of Dallas - Board of Councilors
December 7, 1995

When most people first hear the term 'nanotechnology', they most readily think of the term 'microtechnology': the technology of microelectronics that has so transformed society in the past two decades. And that is really the appropriate analogy. Microtechnology is the technology that allows you to fabricate objects on the micron scale. (Fig. 1)

A micron is a millionth of a meter. You know what a meter is - it's about the distance from the tip of your nose to the end of your hand when you stretch your arm out. You take a little one thousandth of that and you can still see it - it's a millimeter. Image now that you take one side of this little millimeter and touch it to your nose and stretch out the other side to the end of your arm. Now take one thousandth of that. So that's a thousandth of a thousandth (which is a millionth) of a meter, also called a "micron". That is the length scale that is relevant to building devices such as computers, memories, and logic devices -- the wonderful electronics that to a remarkable degree has its true roots here near Dallas, Texas.

Back in 1985 the computer and memory devices that were sold had sizes for the structures being made that were about one micron across, as shown in this slide.

Now in 1995, the current state of the art in the most recent Pentium computer chip, for example, is about a third of that, 350 nanometers, or a third of a micron. It's expected with pretty solid lines of reasoning that a decade from now the size of these microelectronic objects is going to shrink to less than one-tenth of what it was in 1985: a tenth of a micron, which is 100 nanometers. (Fig. 2)

A nanometer is what you get if you take a micron and stick one end of it to your nose and stretch the other end to the length of your arm and take a thousandth of that. That is now a thousandth of a millionth of a meter (a billionth of a meter). It's called a "nanometer".

This nanometer is about as far down in size as it is sensible to go, because from one side of the nanometer to the other there are only about three to five atoms. Although there are smaller things in the universe than atoms, these are not the sort of things you can put in a bottle or play with out in the open. For us, and the things around us in ordinary life, atoms are the ultimate building blocks.

Now when we think in terms of atoms and look at the picture in this slide, we realize that even though this structure is only a millionth of a meter across, it still very big. It must have thousands of atoms across the top of it, and millions -- actually billions -- of atoms on the inside. It is still a piece of the bulk world. But inside that bulk, that one micron object, there is a possibility of a thousand-fold higher level of detail. If you could get down to that nanometer level, and craft the object with atomic precision, the power of your ability to control the behavior of this object would become immense.

The greatest example of that power at present is in every living thing. It requires water to be around - the elixir of life - and I like to call it the "wet side of nanotechnology". All life forms are built up of water-filled cells, little bags of life that are typically several microns across - like the human white blood cell shown in this next slide.

Every one of these cells (Fig. 3) is chock full of thousands of little machines that move around in the wet, water world of the cell doing the business of life -- enzymes, hormones, RNA, and DNA -- all these things you hear about in news stories covering medicine, biotechnology and genetic engineering. These little machines are molecules. They range in size from about one to several tens of nanometers across - they are nanomachines! They are built of thousands to hundred of thousands of atoms. But each and every one of these thousands of atoms is in a precisely engineered place, arranged "just so" in order to make the overall molecular nanomachine function perfectly.

To me the most stunning examples are provided by the enzymes, each of which is a whole chemical factory on a nanometer scale. These enzymes have been evolved over billions of years to make their chemical product about as well as could possibly be done. In most cases the enzymes have reached the limit of perfection. They are the ultimate catalyst for the specific chemical reaction that is their little "job in life". Such molecular nanomachines are what enable life to work, not only in ourselves, but in every plant and bird, in everything you ever thought about that ever crawled on the surface of the earth.

This wet nanotechnology is incredibly powerful. In fact, the more you get to know about it, the more you are drawn in absolute awe. You think of how beautiful your daughter is, or a flower, or how incredible a human eye is that it can see, or a brain that can think. And then you think, this wet side of nanotechnology (what most people call biotechnology) can do anything.

But in spite of this awesome power, there are many things that cannot be done and will never be done on the wet side. One of the most important is conducting electricity, like a metal wire, or like the connections in a computer or even the semiconductors when they are doing their semiconducting. You will never get that (for reasons I cannot go into tonight) out of this biotechnology. In fact, most of the industrial revolution that led to our modern society is not a tribute to biotechnology. It's a tribute to the development of steam engines, and gasoline-powered motors, and all manner of electrical devices, including radios, telephones, TV's and computers -- all of which are technologies from the other side, the dry side. And increasingly I believe this is going to be an area of great development.

Imagine what our world would be like if we really could construct on the dry side, without water and living cells, objects with the degree of atomic perfection that life achieves routinely on the wet side. Imagine for a moment the power of what I like to call the "dry side" of nanotechnology. The list of things you could do with such a technology reads like much of the Christmas Wish List of our civilization.

I've listed a few of them here.

The answer to many of our most pressing problems, to the extent these answers are possible in this universe, will some way or another be found in the dry world on this nanometer length scale. (Fig. 4) This is the driving force behind the development of this area.

In many ways this is the logical extension of chemistry, because chemistry is about putting atoms in particular places and then making a molecular object that is stable so that it can go out in the real world and do good things. Now chemistry has always dealt with objects on an almost nanometer scale. But the technologies on this list are in a sense, CHEMISTRY in big, bold type: an atomically precise technology that lets you build elaborate structures on a scale of 1 to 100 nanometers. Structures that can go out do things that are really important - like storing information, switching electrical signals, converting sunlight to electricity, transporting electricity in super-strong cables for thousands of miles without loss, and converting this electricity into stored chemical energy and back again in the batteries and fuel cells of the 21st century, and on and on and on.

I am not going to get into the details of these new nanotechnologies tonight. Instead, I thought I would talk a bit about the driving force behind their development: the growing problems that will inevitably confront human civilization on this planet over the next 50 years. Problems for which the development of nanotechnology - particularly on the dry side - seems likely to provide the only realistic solutions.

To put it simply, I believe it is clear that we have a little job for nanotechnology. (Fig 5) Except that this job isn't little. It's so big that it will occupy us for many coming decades. he job begins to be evident when we look at the following chart - the world population growth over the past 2000 years. (Fig. 6)

This chart is a plot -- not a artist conception -- but an actual plot of data to the extent it is known, of human population on the surface of this planet for the last 2000 years. At the left we start at year 0 with the birth of Jesus Christ, but of course there was a time before then. In fact, the plot wouldn't look dramatically different if we started even five thousand years before Christ. We are all used to hearing that the world population is going up dramatically, but one of the most remarkable facts evident from this plot is that the world population was stable for so long.

At the time of Christ it is estimated that the population of the planet was about a third of a billion people, three hundred million. It had been about that level since well before the time of Moses. It was that up through the times when Eastern part of the Roman empire was founded in Constantinople, and when Mohammed started the Islamic faith, and the population held about that same level through the time of the battle of Hastings in 1066 -- still about three hundred million people on the planet.

The reason that the world population maintained this stable level was that we were living with an agrarian economy. We didn't have high technology. With an agrarian economy based on muscle power, there is only a certain amount of arable land on the planet, and just a certain number of people that you could feed, and without modern medicines there was a certain level of disease and a resulting rather low average life expectancy. The result was a balance between births and deaths that leveled out at a population of 300 million - a balance that was stable for thousands of years.

But, sometime, about four to five hundred years ago, modern civilization started really taking off with the invention of the printing press beginning the wide dissemination of knowledge throughout Europe, as well as the invention of physical science and the scientific method starting around the time of Galileo. Things started really taking off, as you know, during the industrial revolution primarily in England, with James Watt and the perfection of the steam engine. As a direct result of these new technologies the population rose rapidly. By the time the of the second world war, we were at about two and half billion people on the planet.

Amazingly, the population has now more than doubled just since the second world war. So, more than half this problem has happened during the living memories of either ourselves or of people in our families that are still alive.

You look at this chart and say, "Well, where is the evidence of the Four Horsemen of the Apocalypse? Wasn't that suppose to control the population?" In a sense that and the agrarian economy were what was controlling the population for so many thousands of years. But you notice that, in spite of the Four Horsemen, this world population curve basically only goes up. You might even call it remorseless.

For example, look in this population data for the effects of the worst epidemic that you can ever remember in history. How about the Black Death in Europe? As a population control, that was a good one. It was worth about a third of all Europeans over a fifty year time period. The actual data during that time was not very well kept, but you can see from the data before and afterward, which is pretty firm, that it didn't really matter. If there was a net dip in the population of the planet, it was healed almost immediately. The Black Death wasn't enough to affect this problem long term.

How about war? That's suppose to be pretty good, isn't it? The second world war was a pretty good one if you care about limiting population. That was worth about fifty million people. There isn't a dip there on the population plot either. In fact, if you really look at the data, there's actually a slight acceleration afterward: the baby boom. Its being going up, and up, and up remorselessly.

The biggest driver, actually, has been the development of modern medicine. Something you would think -- and certainly is -- a wonderful advance. People were dying of terrible debilitating diseases, many who never got a chance to live out their first year. And we fixed a lot of that awful problem. A lot of this happened because of the armies that the allies put around the world during the second world war: huge armies in Africa and Asia. When we pulled those armies out, we left behind the medical technology of keeping millions of people healthy. And that, more than anything, had caused this population boom: the medicine of our current high level of civilization.

Now we are at nearly six billion people on this planet. I don't know if this is true but I've been told that two billion of these people don't have access to electricity right now. Somewhere between three and four billion live so far below anything we in this audience would consider to be the poverty line, that we would be appalled. Their chance of living what we would consider a fulfilling life is extraordinary small.

If all the population in North American, Europe, Eastern Europe, and Japan somehow disappeared, still we would have a tremendous population problem on the planet. Something is going to have to happen to change what has never happened before in the history of all civilization. This curve, this remorseless rise in population is going to have to stop.

There are therefore two crucial questions: "How is it going to stop?", and "How are we going to take care of the people who are going to be around when it does stop?"

So what's the future going to hold? Amazingly, I find many people believe the black curve in the next slide, the Armageddon Scenario, (Fig. 7) is the most likely future for the world.

This Malthusian scenario is a projection that says that sometime (and, in fact, if you look at the chart, its seems pretty likely that it will be within the next 50 years) a nuclear weapon exchange, or a new virus, or something else will cause this population problem to solve itself. I encourage you to talk with your friends and find out what they believe. My experience is that over half the people I talk to actually think this will happen.

I don't think it will. I think that the scenario I've marked on this slide in green is more likely. As shown in more detail on this next slide, this green scenario is the best estimate of the United Nations of what population trends will be for next couple hundred years. This is a hopeful scenario, but I believe it is realistic.

Here we see that in 1995 we are already about at the inflection point, and we are going to stabilize. This is about as optimistic as you can get for the next fifty years because we know what the demographics is of women currently in the population pool. They are going to have a certain number of children. We are not going to stop at six billion, virtually inevitable we will go to at least ten. (Fig. 8)

And the question now is: "Can we sustain this? Can we have this planet with ten billion plus people on it, and have a stable world civilization, and give everybody -- every one of these ten billion people -- a reasonable lifestyle? "

It's not obvious that we can. In fact, it is becoming fairly clear that we cannot - not with the current technology base.

If you kept with the current technology, you might say: "Well look, we have a lot of coal, oil, and gas, and we can burn that. We've got a lot of ground we can irrigate. We can probably handle ten billion people and things won't change. Is there any evidence that the planet is being challenged by the population that we have already?"

Well, it turns out that the scientific evidence concluding that the planet is already being challenged is really getting to be quite solid. I will give you a quick synopsis.

The first lesson to be learned from the scientific evidence is that life actually has long had control over this planet.

The atmosphere that we have around us was built by life and is controlled by life. (Fig. 9) When the planet was first born, we did not have any oxygen in the environment. It was mostly nitrogen and carbon dioxide. Life, at least elementary life, was formed very rapidly in the beginning within about a half a billion years of the formation of the planet. And early on, about one billion years, photosynthesis was developed and started generating oxygen. It took about one and half billion years to precipitate out all the iron out of the ocean until the oxygen the atmosphere started going up. Then it finally leveled out, not because photosynthesis got tired, but because animals started to be developed and they breathed oxygen. And for roughly a billion years the atmosphere has been controlled by life, by the balance between plants and animals.

It is a striking thing to realize. You wouldn't think life could be that important. But it has long since controlled the planet's atmosphere. And it's been doing a fine job of it.

Just recently, though, we have a life form that has started to tip the balance. You might have already heard reports about this, but one thing that is very striking is to see what the real scientific data looks like, and where it comes from. We actually have a great record of what the atmosphere has been on this planet for the past 150,000 years. It comes from boring into the ice caps in Greenland and Antarctica. Because the farther down into the ice caps one drills, the older the ice is.

It turns out when you go down to get a little ice cube, from say five hundred feet down in these ancient ice caps, and you take it out and you put it in a place where you pump the air out and melt the ice, bubbles come out. This air was trapped between the snowflakes that fell and was compacted to form the ice thousands of years ago. (Fig. 10) Very careful analysis has been done to make sure that this air hasn't changed its composition in the intervening time, and we are quite sure this is safe data. So we can look now at what the atmosphere actually was like on the planet as deep as these ice caps will let us go - a little over 150,000 years (which incidentally is about to the age of the human genome). So we have knowledge of what the atmosphere has been during basically the entire human experience of this planet.

Here's all the data. (Fig. 11) And plotted on the top is carbon dioxide and, lower down the chart in green is methane gas (natural gas) over these time periods. The concentration of these gases have gone up and down because we have had two ice ages over this period. We're just coming out of the last ice age, about 10,000 years ago. In fact, human civilization started with the end of this last ice age.

Therefore we know what the carbon dioxide level has been for this time period. During the hottest period for the previous interglacial, which is about 110,000 years ago, the peak on the right-hand side, the highest level that CO2 ever had been during the last 110,000 years was 300 parts per million, about 0.03%. Well, you may be able to see it as I have drawn in a nearly vertical yellow line on the left-hand side, corresponding to the last 200 years. The current CO2 level concentration is about 370 parts per million, and almost all of that rise has happened since the industrial revolution.

Methane, which turns out to be an important greenhouse gas as well, comes primarily from the decay of organic matter under water. For example, when you make rice in flooded fields, you produce a tremendous amount of methane from those fields. Making food makes methane, which gets into the atmosphere and actually warms the planet, sort of like a blanket around the earth. The highest methane has ever been in the last 150,000 years was 700 parts per million, but now it is 1,700, almost 2½ times what it was, and all of that increase is a result of modern civilization.

This rapid change in the composition of the atmosphere has happened over the last 200 years-it is more rapid a change than at any time during the last 150,000 years of the planet. Here is the carbon dioxide data since about 800 up unto the present time. (Fig. 12) Basically, it's a level line and had been level for a thousand years, and then it starts turning up about 1800 and then it's been going up ever since. There is no question why that line is going up. It's because of the technology of the industrial revolution where we started burning coal and wood in vast amounts, and people started multiplying and producing more and more.

This is more of the data showing you that methane started coming up at the same time. (Fig. 13) There is no question from where the methane is coming. It's not just human beings, it's civilization, modern civilization that is causing the change in the planet.

Many people argue that maybe the planet can adjust and absorb this. Well, evidently it can't keep the CO2 level where it was, because we're actually pouring even more into the environment than we were back in the early 1800's and it was already starting up then. The planet is unable to control at the levels of the pollutants that we are putting into the atmosphere right now. Of course, ultimately if you give it enough time, it will adjust to a new steady state, but for carbon dioxide in particular, it's expected it would take over 200 years for the planet to finally reach some equilibrium.

In this next slide (Fig. 14) you can see in the data collected more recently from the top of Mauna Loa in Hawaii, looking at carbon dioxide in the atmosphere, and also from Barrow in Alaska, Samoa, and the South Pole, and now you see yearly oscillations of carbon dioxide going up and down because of the growth and die-back of vegetation in the Northern Hemisphere, where most of the land mass is on this planet. The magnitude of oscillation obviously depends on where you are on the planet, but there's no question that the overall level of CO2 is going up.

Now up to a few years ago some scientists were peering at the last part of the curve, where it looks that maybe it started to level off and slow down. But just recently there had been a very careful measurement and analysis in an article in Nature magazine, (Fig. 15) the bottom line of which is no, the dip was just a little fluctuation and now the slope is back up. Nothing is stopping this. It's going up and up and we have hardly begun to burn the carbon that we are going to burn, as China, for example, continues to develop.

So there's no mystery, no argument that carbon dioxide and methane are going up. There's no argument that it's coming from civilization. We don't know how to stop it. The question is "is it starting to do anything yet to the climate?"

There is also an important molecule called N20, nitrous oxide, which actually is a colorless molecule, it's very innocuous, except it's a greenhouse gas that floats up into the stratosphere, breaks apart and starts destroying the ozone. This is the N20 production over the past 100 years or so. (Fig. 16) There's no question where that is coming from. It mimics the production of fertilizer in the world.

Fertilizer, you ask, "What could be bad about fertilizer?" Well, nothing is particularly bad about it except that it helps to grow plants that when they decay anaerobically put more of this gas into the atmosphere that the planet is not readily able to control. (Fig. 17) Ultimately, of course, .there will be some new leveling off. One wonders what the planet will be like then.

Are these new gases warming the planet now? Well, there is also no question amongst anyone who looks at this that there has been a warming of the planet in the past 100 years or so since data has been collected-both in the Northern and Southern hemisphere the average surface temperature of the planet has gone up about 0.6 of a degree centigrade over this time period. (Fig. 18)

Recently, it has been getting warmer faster and the issue is why.

This is the temperature deviation from an baseline around the 1950's of the yearly average surface temperature of the earth. This is now very carefully collected data from all over the planet. And you can see that the last decade has been abnormally warm. (Fig. 19) Those of you that are close enough to see it, will notice that back in 1990 we had at that time what was an unprecedentedly warm year. That was about the time that global warming became an issue in the worldwide press. It was quite heavily hyped: there were pictures of New York City being halfway under water. Then there was enough discussion going on with sensible people that showed that, well, this extra greenhouse gas warming isn't really so clear, these hot years may be just a fluctuation. And just about that time, Mount Pinatubo went off in the Philippines and threw a lot of dust up in the stratosphere, changed the average albedo of the earth and we actually started cooling down a little bit. And those two reasons are why we haven't heard very much about this in the press since then.

But by the beginning of 1994, last year, the dust from Mount Pinatubo had settled out of the atmosphere and the warming resumed. And 1994 was the third hottest year in history. We're currently almost done with 1995. If we took the numbers we have at this moment, 1995 would be the hottest year in history. So whether this is a fluctuation, or this is the beginning of the signature of global warming caused by civilization's increase in CO2 and other green house gases in the atmosphere, that's the issue.

Now there is an international organization that looks at this, the Intergovernmental Panel on Climate Change, a very substantial organization of thousands of scientists around the world, involving the science and technology agencies of essentially every government in the United Nations. Their report is coming out now in about two weeks. It will say for the first time that the signature of global warming is now evident in the record and we are beginning to see the effects. The effects are still small, but they are there.

The next question is what happens in the future-what can we predict. The trouble is we probably cannot predict very well in advance because the earth is, as we say in technical circles, not a linear system. It's not just that our average temperature is going to go up by a degree or so (centigrade) every two decades. It's a nonlinear, complex system. I don't want take the time to tell you what these mathematical terms mean, except to say that the earth's climate a sort of system that if you perturb it past a certain point, it will say "Okay, now I'm going to do something completely different."

Remember the "butterfly effect" so memorably discussed in the movie Jurasic Park? Instead of a butterfly in China changing the weather in Texas, we're concerned here about passing a threshold in the amount of greenhouse gases in the atmosphere changing the climate of the world.

If you want to talk to me later, I can tell you about a few of the things that we're specially worried about that can change the climates of particular regions of the planet because, for example, ocean currents suddenly stop going where they used to go. We're also worried about changes that happen so rapidly that local ecologies cannot adapt to it. Forests, for example, will gradually move forward to accommodate to climate change, but what happens if the temperature changes so quickly that the forests don't have 1,000 years they need to start marching off in the right direction?

So the indication is that human-induced climate change has already begun. This conclusion still may be wrong. The effects are small. Maybe it hasn't begun yet. But the "street talk" is that probably it has already.

Well, what are we going to do about it? We have 6 billion people on this planet. Over two-thirds of these, roughly 4 billion people, live in undeveloped countries. And they are not going to go away unless there is some completely unprecedented holocaust, and we certainly don't want that. As the information age spreads within this undeveloped world, perceptions of vast imbalances in well-being will become vastly destabilizing.

These billions of people are all going to have to be brought up to a reasonable lifestyle- in fact they're going to insist on it. We in the highly developed part of the world can talk to each other about riding our bicycles to work and using solar power. But you're not going to tell the billions of people living in undeveloped countries to keep riding bicycles, avoid the cheap, dirty power of our current oil and coal technology and still live in misery. They're going to burn all the oil and coal they can. It's predicted within the next 10 years that the CO2 production in China alone will become larger than all we're currently putting out over the planet right now.

We're going to have to have at least the increase in the energy production depicted in this slide (Fig. 20) by going from the little black dot on the left to the big black dot on the right for the estimated energy usage by the middle of the next century. And actually that's very pessimistic. That still assumes that a huge imbalance persists between the developed and underdeveloped world. It really ought to be about 5 to 10 times that amount to bring what will become about 10 billion people up to a reasonable lifestyle.

Currently 95% of all energy produced in the world is made one way or another by burning carbon, carbon dioxide in the atmosphere. If it is true that we're starting to see this signature of climate change already, we've got to stop this. We cannot go to the big black dot with carbon burning. If it's not true, we'll be very lucky. If you wonder or hope that it's not true, just remember we're playing a giant experiment with this planet and its a very complex, nonlinear system for which we cannot predict it's outcome. Once it becomes clear that it's starting to have an effect, we aren't going to be able to suddenly fix it, because the length of time it takes for carbon dioxide to equilibrate with the oceans is estimated to be 100-200 years.

It is as though you're asleep and it's very hot in your dream, you're sweating. It's just insufferable. But then you wake up, and it is insufferable, and you are sweating, you're not in a dream, it really is hot. So you take your arm and try to throw the blanket off. Except there isn't a blanket, or in a sense there is-the atmosphere of the planet is the blanket- and it will take about 100 years to change that blanket. So there is a reason to worry about this now, even before the warming becomes insufferable.

And the question is, "What do we do about it?"

One answer is okay we'll all tax ourselves every time we burn a pound of carbon we'll pay some number of dollars into a giant fund and then start trying to help this problem go away in the third world. It's never going to work, the amount of money involved is too great, and the incentives are too diffuse. In fact I think there is only one answer. We have to find a way of making that big black dot on the right hand side of this picture out of clean energy that is so cheap that there is no longer any incentive to burn coal, gas, or oil.

There's really only two ways to do that right now. One is nuclear fission. We can hope for nuclear fusion, but this data actually comes off the WWW from Princeton Plasma Physics Laboratory, which is dedicated to doing energy production by nuclear fusion, and their most optimistic scenario does not have them taking a very big hunk of that big dot with nuclear fusion by 50 years from now. It may be that in a 100 years they can do it, but not 50.

No, if the answer over these next 20-50 years is nuclear, it highly unlikely to be fusion. It will have to be fission. Now maybe in the U.S., Europe and Japan, we can assure ourselves that we can produce most of our power by nuclear fission safely, with no Chernobyl's, no Three Mile Islands. I think that's quite possible. And maybe we can find ways of sequestering the waste which will be radioactive for ten's of thousand's of years, and we'll promise you -- even though our civilization is only 200 years old -- we promise you: "okay trust us - we're going to take care of it for 20,000 years". But, that will take care of no more than about a quarter of the big black dot. The other three quarters of the world is going to have stop producing carbon dioxide as well. How about all of the 185 countries in the United Nations being nuclear?

In fact there is a question as to whether you could do it: do the whole black dot with nuclear fission of uranium. Is there enough uranium 235 to do it? Probably not. Most likely the big black dot would have to come from breeder reactors. Imagine the world in 2050, with a 100 nations running breeder reactors. It doesn't sound like a very stable world.

What is the alternative? Wind power? There isn't enough wind on the earth to take care of very much of that big black dot.

There's really only one other alternative: solar. But right now the fraction in the world for energy production that is solar is laughably small-less than 1%. And although we have solar technologies we could roll out right now that could take maybe 10% of the black dot, we haven't got a clue how to do the whole black dot. That's got to come from somewhere new - a brand new technology.

Could it happen? Could we provide for all the world's energy needs with solar power? The answer is clearly, Yes! It turns out on a square of West Texas, 100 miles on a side, there is enough light coming down that if you can collect that and turn it into transportable energy at 10% efficiency, you could take care of our current little black dot, just 100 x 100 = 10,000 square miles of Texas ( or maybe only 90,000 square miles of Arizona). So there's plenty of light coming down. Striking the earth every year there is over 10,000 times more solar energy than required to provide for the worlds expected energy needs in 2050, the big black dot.

So, in principal, you could do it with solar energy, but we don't know how to do it yet. We don't have any technology now that if we just apply it within a ten year time horizon it can begin to be affect the problems we have been talking about. But on the other hand, we can really imagine that there could be technologies that would do it. And when you think about what those would be, it turns out you could take nearly each and every photon, every little corpuscle of light that hits the earth even on a cloudy day wherever you put these solar collectors, and change it efficiently into some form of stored energy.

In this super-efficient, low light level, solar energy converter of the future, down 'where the rubber meets the road', where that photon turns into stored energy, that's going to occur on a length scale less than the wavelength of the sunlight (about 400 to 1000 nanometers), and it's going to have to store the energy somehow: chemically, or as an electron going up into some sort of capacitor, or something like that. All this, intrinsically, is going to have to occur on the nanometer scale. It will be a nanotechnology. And we need it desperately.

So it turns out that with such a solar nanotechnology you could create a solar power industry which could actually start solving some of these global environmental problems-it does have the muscles to address this energy issue worldwide.

I use to think that we have 100's of years to solve this problem. But for the reasons I've discussed - this explosive growth in the world population, and the vast poverty of billions of people --I'm not so sure we have 100's of years. Maybe this problem becomes critical within only a couple of decades. World energy production is such a huge enterprise: tens to hundreds of trillions of dollars of installed plants around the world. You aren't going to change that just by saying I've got some great new technology, shut your plants down, we'll just build this wonderful new nanotech solar industry to replace them. It's going to take at least 20 years to roll that out and we don't have the technology to do it yet. So I think we've got to get busy.

Incidentally, I'm going to put this in since this is a Texas audience. A special thing has happened in Texas just recently. This is a plot from the strategic plan for energy for the state of Texas. (Fig. 21) There are a number of curves. One is this red line, the consumption of energy in the state of Texas has been going up linearly for some time. Actually Texas is the biggest consumer of energy in the country-40% more energy consumed in Texas than in the state of California for example And the green line is the production of energy in the state of Texas. And just recently the green line went under the red line, so Texas is now a net energy importing state. Very few people in the state of Texas believe the green line is going to start heading back up. And almost no one in the state of Texas wants the red line to come around and head down.

The projection is that by the year 2005, ten years from now, every year \$10 billion will leave the state of Texas and will go somewhere else to buy energy to cover the state. This strategic plan is rather interesting because it shows that, if you believe what's in it -- and I'm not sure that I do, that Texas turns out to be very rich in renewable resources, solar and wind, and we could actually pretty well track this dotted green line with renewable resources. Of course that would make a tremendous impact on the finances in the state of Texas.

To me the issue is not so much that we need to find a way to make Texas rich, and economically powerful while beggaring our neighbors, or to make the USA economically better off than the rest of the world. It seems to me, the real issue is the rest of the world, the four billion people who live in the undeveloped nations. We can't afford to beggar them because in the end it will be a tremendously unstable planet both politically and environmentally. We're going to have to solve the problem with high technology. I think we can.

If you get into discussions like this with people, depending upon their political persuasion, they'll say "You darn technologists! You got us into this problem. Why don't you just stop, and leave us alone?" In fact back in the 60's it was popular among some in my age group to think the answer was for everyone to go back to the farm, live a nice simple life and everything would be okay again. But remember that curve, the population of the planet prior to the industrial revolution. Somewhere between 0.3 and 1 billion is the number you can support on this planet with an agrarian economy. Now for those people, maybe it was a good life, though I'm not at all convinced it was all that good. But to sustain this level with a low-tech, agrarian way of life, you will have to go to the other 5+ billion people on the planet and say something like: "Excuse me, I hate to tell you this, but you're just awfully inconvenient; wouldn't you please go away? The rest of us want to live happily on the farm, and there just isn't room for you." (Fig. 22)

On the other hand, I agree with many who point out that the full answer cannot be just technology. In the long run, the world population problem can only be solved by a change in world culture, and probably the most important single factor will be the improved status and self-image of women. Not so much in this case in the developed countries where the fertility rates are generally already acceptable, but in the third world where the majority of the population growth has occurred since the second world war. I understand that there are still areas in rural China, for example, where women don't even have given names. A woman is only known by her husband's name. It is still true for most of the 3 billion women on this planet that they live in a culture where their lives have worth only through their ability to raise children. So the women's liberation movement in general, and in the third world in particular, will be of vital importance in solving the population problem.

Even given that, even if we stop population growth somewhere between 6 and 10 billion people, we can't sustain even the current population with the current technology. So for the 50 years, there's really only one good alternative: we need more technology, not less. It has to be green, it has to be clean, and it has to be closed loop. And I am confident that in almost every area the keys to these technologies are going to come when we start learning how to put things together one atom at a time on the nanometer scale.

We've got to learn how to build machines, materials, and devices with the ultimate finesse that life has always used: atom by atom, on the same nanometer scale as the machinery in living cells. But now we've got to learn how to extend this now to the dry world. We need to develop nanotechnology both on the wet and dry sides. We need it urgently to get through these next 50 years. It will be a challenge. But, I am confident we will succeed.