 Today we're going to talk a little bit about making measurements of carbon dioxide, the gas that you exhale from space. But before we get into that, we're going to step back a little bit and I'm going to try to give you a brief overview of why we might care about this invisible odorless gas and what it's doing not so much in our climate system, but basically just how it passes through the system. We'll then learn some things about carbon dioxide that might surprise you. You might know about human emissions of carbon dioxide, and you might know some other things and we'll start with some of those. But as we go through this presentation, what I want you to do is to maybe start to rethink what you thought you knew about carbon dioxide, what we might learn about carbon dioxide, and how that might change maybe even the way that we proceed through the climate negotiations that are going on in Paris. We have here a picture of a spacecraft flying across the northern hemisphere. This is actually like Michigan, it's flying near, and this is basically where we are today making good measurements above the Earth. So we're going to be talking about the orbiting carbon observatory too, a NASA spacecraft we launched about a year ago, but once again, before we get there, we're going to start with something very much simpler, something called the natural carbon cycle. Believe it or not, you guys actually already know about this. You learned about it in grade school. What you learned about in grade school is that every year, as trees put on leaves, they absorb sunlight and carbon dioxide from the air. They inhale the gas that we exhale. What you may not remember is that every molecule in carbon, which makes up most of that tree, comes from carbon dioxide from the air. And every year, as trees in the northern hemisphere start blooming, they actually pull so much carbon dioxide out of the air that we can measure it with our instruments displayed around the surface of the Earth. And the amount of carbon dioxide they pull out of the air every year is one to two percent of the carbon dioxide in our atmosphere. And they've been doing that year in and year out. So spring and summer they pull carbon dioxide out, fall and winter they put most of that carbon dioxide right back into the air. You're going to see a little bit more of that in a minute. So you remember all of that? You learned that in grade school, right? But now, notice that the slope is going up a little bit here and to the right. The amount of carbon dioxide in our system is increasing over time from values that actually we've actually seen about a 40 percent increase in the carbon dioxide abundance of our atmosphere since the beginning of the industrial age. And now, as human beings, we're actually a major contributor to this global carbon cycle that we're talking about. Primarily by burning fossil fuels to heat our homes for transportation and for other activities, we're putting a lot of carbon dioxide into our atmosphere. How much you might ask? Well, it turns out it's about 40 billion tons of carbon dioxide that human activities are adding to the atmosphere every year. How much is that? About five and a half tons of carbon dioxide for every man, woman, and child on the planet. It's a lot. How much carbon dioxide is that in reference to how much we have in the atmosphere? It's enough to increase the carbon dioxide abundance of our atmosphere by 1 percent per year. In a century, at this rate, we would double the carbon dioxide abundance in our atmosphere. We've been making, and we actually know that because we've been making very detailed measurements of carbon dioxide over the entire earth since about 1958. And here we see a record that starts in 1979 when the carbon dioxide abundance of the atmosphere was about 333 parts per million. We measure carbon dioxide in parts per million, and so that's what you see. You also see what's going on here. These are stations, an increasing number of stations that we're putting from pole to pole, south pole to north pole. This is the northern hemisphere. Notice it's going up and down. That's the earth breathing. Spring, summer, fall, winter. Spring, summer, fall, winter. Isn't that neat? We can actually measure that signature with our instruments on the ground. Now, these are where our instruments on the ground are. We have more and more of them every year, between 100 and 150 of them reporting every week. But what they're showing us is that the carbon dioxide, as we've seen here, has just been moving up and up and up and up, hitting about 400 parts per million now, very, very regularly every year. That's a 20 percent increase in the carbon dioxide since we've been making this measurement. We've changed the atmospheric concentration of carbon dioxide by 20 percent since 1979. And we know that because we make very accurate measurements of this gas from a whole host of sites around the world. But that's just half the story. And that's not even the interesting part. The interesting part kind of starts here. I told you we know how much carbon dioxide is building up in the atmosphere. And also, we know how much carbon dioxide we're putting into the atmosphere pretty accurately. That's what's shown with this gray curve that's going from the lower left to the upper right. This is the amount of carbon dioxide produced by fossil fuel combustion. As we burned more and more fossil fuels faster and faster since the 1960s shown here, we've actually increased the amount of carbon dioxide emissions from that. How do we know that? Well, we know that because people tax fossil fuels. They keep pretty good records of how much is mine, how much is transported, how much is actually burned every year. The uncertainties are shown by the gray up there. You see how much uncertainty there is on this? So we know how much carbon dioxide we're putting into our atmosphere from that. Another thing that's much more uncertain is by land use change. So let's look at that. So carbon dioxide from fossil fuels, yeah, we know what that is. But land use changes, flash and burn, agriculture, deforestation, things like that. It's also producing an increase in the carbon dioxide abundance of the atmosphere. But how much is it increasing the carbon dioxide in the atmosphere? How much do these two terms contribute to the increase in carbon dioxide that I showed you on the previous presentation? How much? Shouldn't it just be just add these two numbers together and if it all stayed there, that's what you would see, right? That's not what we see. Because I told you we're making very detailed measurements of carbon dioxide in the atmosphere every year. All you have to do is integrate them and say, how much gets added every year? And the answer is weird. This curve shows the atmospheric buildup. It is not the sum of these two curves. It's half of those two curves. Only half of the carbon dioxide we add to our atmosphere every year by burning fossil fuels stays there, on average. The other half is being absorbed by the oceans and by the land plants somewhere on the planet. We know how much is going into the ocean because as it goes into the ocean, it makes the ocean more acidic. We're acidifying our oceans. Why do we carbonate soft drinks? Our beer keeps things from growing in it. We are carbonating our oceans. 10 billion tons a year of carbon dioxide generated by burning of fossil fuels is ending up in the ocean. But that's really weird. And we can measure that pretty accurately, too. But the really weird thing is that somewhere, 10 billion tons of carbon dioxide is going into the land, into trees. That's more carbon dioxide difference every year absorbed by every forest known across Eurasia. It's a big thing. Have you seen a new rainforest spring out of someplace every year for the last maybe 50 years? That's how much carbon dioxide we're talking about, disappearing somewhere into the system and we don't know where. So what natural processes are absorbing half of the carbon dioxide we're emitting? We don't know. Another weird thing, notice how smooth the inputs of carbon dioxide are into our system, but also notice that some years, almost 100% of the carbon dioxide we put into the atmosphere stays there. Other years, very soon afterwards, almost none. What's going on there? Could it be that the processes that are absorbing carbon dioxide in our system are being affected by small scale climate changes, by drought, by El Nino? Could it be that some of those processes are determining whether all or none of the carbon dioxide we put in the atmosphere is staying there? Actually, from the existing measurements, I'm afraid the answer is still is, we don't know. That's where we are today. But you might be wondering, why is it so hard to find 10 billion tons of carbon dioxide? Don't we know how to do this? Well, the answer is kind of weird, but it looks like this. This is a model of carbon dioxide as it's put into our atmosphere by every process we know about, by biomass burning in the Amazon and in Africa, this is just biomass burning, by industrial emissions in China and North America and Europe, the very best model we have ever run to show us how this works. But what is it showing us? It's showing us that when carbon dioxide is added to the air, it's picked up and transported by the winds. This stuff, every molecule of carbon dioxide we emit, hangs around on average, if it survives a year, for 300 to 1,000 years. And it's transported and mixed by the winds. And there's a lot of carbon dioxide in the atmosphere already. So even the largest human activities only change the carbon dioxide abundance by one to 2%, most of them by a fraction of 1%. The largest changes you're seeing here from the reddest reds to the bluest blues is 2%. That's all you get. It's an incredibly hard measurement to make. Now, notice when we first started talking how red it was up there, that's because we started this movie in January when the Northern Hemisphere land plants were all dormant. As we've been talking, we've gone through March, April, May, June. Those plants are in their wonderbred years. They're actually pulling very strongly, drawing carbon dioxide out of the air. And look at what it's doing. It's absorbing all of that carbon dioxide up there. This is that spring drawdown. This is what we know happens every year. So this is what's been going on. It's a very complicated system, but if we could crack this system and actually make measurements as good as this model, this model, by the way, is wrong. We ran it for two years, guess what? It'd get the wrong answer. First year, it'd run fine, but it doesn't have that sink in it that's absorbing that extra 10 billion tons over land. And so it'd get it wrong the next year. The CO2 amount would increase too fast. So that's where we are. We don't know it today because it's a very complicated system. One way to improve our chances of studying this system is do just what we did for weather. I told you before that we understand what we're carbon dioxide is going in our system because we have about 150 stations around the globe making these measurements right now. How well could you predict the weather if you had only 150 weather stations? About as well as we could do in 1930? Not so good. The way we've revolutionized weather prediction is to fly a bunch of satellites in space and make a lot of observations from those satellites and then actually start to study things like surface temperatures, precipitation, where the plants are growing, how the ice is evolving over time, and other factors, other things that we've learned to study. So we've gone to space to study these things and finally, even though this turns out being a very hard problem, it took until about 2000 before a couple of groups finally started to understand how we might measure an invisible gas from space to an accuracy of a couple parts per thousand. It's just hard. I led a group back in 2000 that came up with a measurement concept and measuring the absorption of reflected sunlight as the light goes from the sun to the surface up to the satellite. Carbon dioxide, like other gases, absorbs only certain colors of light. We monitor those colors very, very accurately with a very, very sensitive instrument with parts and pieces derived from things like the Hubble Space Telescope and we were able to actually make a measurement. So we put all of this stuff together, we put it into a proposal and we proposed it to NASA as a competition with 30 other possible Earth science measurements like some of those you just saw. We won. So we started building the Orbiting Carbon Observatory in 2001. A couple of years later, our colleagues in Japan started putting together the greenhouse gases observing satellite and this actually was a much more ambitious mission than ours, it cost about three times as much, it's about three times as big and it measures methane, the second most important greenhouse gas as well as carbon dioxide. Very, very important. So almost immediately after they got started they actually sent me a message saying let's get together and work together on these two satellites. We're trying to make the hardest measurement that has ever been made from space. Let's get together and work together and see if we can cross calibrate these two instruments and maybe get measurements we could eventually combine to learn even more about carbon dioxide in our system. We of course said yes, we started working together instantly and we basically have been working together very, very closely ever since. We also had a little race to the launch pad. They won. They got to the launch pad on January 23rd and had a beautiful January 23rd 2009 and had an absolutely beautiful launch on an H2A booster, got them into space. They've been operating since that time very, very well. About a month later my team finally got to the launch pad and we had it at three o'clock in the morning but also looked like an absolutely beautiful launch right up to that point where you see the line kind of disappear there. At that point the nose cone of the rocket was supposed to split open and be ejected and it didn't happen. We made it to 635 kilometers, our target altitude, at one kilometer per second too slow to go into orbit. We fell back to Earth and burned up just off the coast of Antarctica. The whole mission which took a thousand man years over a nine year period to build lasted less than 10 minutes. Not my best day. But it wasn't over then, even for us because it turns out the thing that survived was the collaboration that we had started the Japanese. They had a spacecraft in space that was operating beautifully. So before the sun came up on that bad morning for me their team came to me and said come work with us. Come help us analyze the data from the greenhouse gases observing satellite. Working together we can work twice as fast. We can learn twice as much and that's what we've been doing. We've been calibrating the system by running around the desert of Nevada every summer with a whole bunch of equipment including some high altitude airplanes. They carry our instruments, we measure carbon dioxide above the site. We also started taking the data collected by GOSAT and estimating carbon dioxide from it. Our team did this independently from the Japanese team. We combined the results, compared them and started learning what we were getting right and what we were getting wrong. This was an incredibly useful capability. We also validated these results that we were calculating against some standards that we have distributed around the world. We put very, very sophisticated uplooking spectrometers into shipping containers. As you can see we have about 21 of those around the world right now. I have a telescope dome on top and some other meteorological instruments. It makes a measurement the same as the satellite makes but at about 20 times the precision and accuracy. So we were able to actually start learning how much we really could learn from these measurements while we were doing this. But that wasn't where it ended either because the next step of course was while we were doing that, NASA came to the right decision and decided to rebuild the orbiting carbon observatory too. And that's what we've been doing. We finally, a year ago in July, on July 2nd, just before 3 a.m., we had another opportunity on a much more reliable launch vehicle. NASA's most reliable launch vehicle, the Delta II. So we had an absolutely beautiful launch. If you went to it, by the way, you saw it on a television monitor just like that just because it was rainy and foggy and we couldn't see the launch. In any case, about an hour later, a camera on the launch vehicle started sending back images showing us the separation of the satellite from the launch vehicle. We were in space. We were on our way to having an absolutely beautiful mission. So we've been flying over the earth making measurements. As the satellite flies along, it orbits the earth 14 and a half times each day and it makes measurements of carbon dioxide along a narrow track, but it makes a lot of measurements. It collects 24 measurements every second as it's flying along and so it gathers about a million measurements a day. Only about 130,000 of those measurements are sufficiently cloud-free to measure carbon dioxide all the way down to the surface. But that's 130,000 measurements. We were getting about 150 measurements from the ground each day. We were getting about 1,000 measurements from GOSAT each day. 130,000 measurements. These are real measurements. Notice how it's red up in the north. That's higher CO2. Green down in the south, lower CO2. Two reasons for that. This starts at the beginning of the growing season in mid-May and we're now running into June and now notice how Asia's getting some green through it. Isn't that interesting? That's lower CO2. North America as well is beginning to see a few green points as the plants start waking up and pulling that carbon dioxide out of the air. Something we've always expected, but this is the first time we've ever seen it at this resolution with real measurements that were accurate enough to really tell that story and look at how it's actually working just like we expected it to. Somewhere in there are the processes that are pulling the carbon dioxide out of the air. We don't know exactly where yet, but we're still looking. One of the other things we're continuing to do as we move through time is to make measurements of carbon dioxide over isolated spots. Here I'm looking at the measurements. We're making over Los Angeles, California. That's my home. That's Caltech right there with the star. And we have one of those uplooking spectrometers there acting as a validation station. So as we fly over, we don't take tens or hundreds, but thousands of measurements over that site and we can determine just how accurate our measurements are and they're doing just fine. They're giving us the accuracies we need. We started making measurements of carbon dioxide from space back in about 2002 with a satellite called Skiamaki which was launched by the European Space Agency. It made great measurements, but they didn't have quite the precision or the accuracy needed to really start answering these questions because the largest changes you saw there were about 2%. That was about the accuracy of the measurements made by that satellite. In other words, I could walk out and guess the CO2 about as well as the satellite could tell us. But then GOSAT launched in 2009 and we started collecting about 1,000 good measurements a day over the earth and that started to really answer some questions, but it really wasn't enough data. Then we launched OCO2 and now we're working very closely with GOSAT gathering another 130,000 measurements a day to add to the 1,000 that we're getting from GOSAT and we're now in poise to make some really great breakthroughs with this data as we finish our first year in space and we see the earth inhale and exhale once. But that's just the beginning of a very long story because next year in June, the Chinese launch their first satellite called Tansat. This is like measurements of carbon dioxide all over the earth. They're planning to apply it right behind OCO2 so they can validate their measurements against ours. A couple of years later, the GOSAT team in Japan is gonna launch the next generation of their satellite with more capabilities and more sensitivity measuring gases in addition to carbon dioxide, methane and carbon dioxide, both, and carbon monoxide so we can see where the carbon dioxide's coming from. Right after that, well, when we made the OCO2 instrument, we actually made a spare and NASA wants to fly the spare on the International Space Station. We're installing that in 2018 that everything goes as planned. So we'll get even more measurements. The French and the Germans got together and they're gonna make measurements of methane using a new technology that uses LiDAR. They carry their own light source. We use daylight and you might have noticed the coverage is not great because in some parts of the world, there's no daylight in some parts of the air. They carry their own light source for methane. And then finally, this mission will be the first mission that will make a lot more measurements than OCO2. So while we make a little line of measurements, they'll take images of carbon dioxide over the entire planet, covering the whole earth every couple of weeks. So now we're trying to tie all these guys together so we can start talking about greenhouse gases with the same precision. So, where are we today? You all know we can only manage what we can measure. Up until now, we really haven't been able to monitor greenhouse gases with the kind of accuracy needed. To answer the fundamental questions we needed to answer about carbon dioxide, it's emission sources, the processes controlling it in our atmosphere. We have that capability today. We have verified the technology to do this. Those satellites are not cheap, but they're not that expensive either. And when we were selling OCO2 back to NASA, somebody asked me how much it cost and I told them it cost four hours in Iraq. Four hours between breakfast and lunch on Sunday. They spend more fighting a war than it cost to launch one of these satellites. We're hoping that as time goes on, we'll have a fleet of satellites making high resolution measurements of carbon dioxide and other greenhouse gases over the entire planet. How will that change the equation? How will that change the way that we think about managing greenhouse gases? How will that change our ability to assess the veracity, the capabilities of greenhouse gas mitigation strategies? How will that help us in the future? Thank you very much for your attention. Thank you.