 I'd like to take a minute to explain the background in the lecture series and then I'll hand it off to UCAR President Tony Busilaki to introduce our lecturer. Dr. Walter Orr Roberts was a visionary and a trailblazer. In 1940, he set up the High Altitude Observatory on the Continental Divide at Climax, Colorado, which evolved over the years from a one-man operation to a research division of NCAR. In 1960, the National Science Foundation asked Dr. Roberts to be the director of the newly formed National Center for Atmospheric Research, which he headed until 1968. He simultaneously held the UCAR presidency from its inception in 1960 until 1973. Dr. Roberts was influential in establishing Boulder's space and rocket science communities that later spawned the University of Colorado's Joint Institute for Laboratory Astrophysics and Ball Brothers Research Corporation, which is now Ball Aerospace Systems Division. The Walter Orr Roberts Distinguished Lecture was established in 1998 and it's supported by private donations, including donations of members of Dr. Roberts's family. And it serves as part of NCAR's and UCAR's public outreach to the broader community. Since that time, we have hosted 12 distinguished lecturers, most recently, Katherine Hayhoe, Richard Alley, Kerry Emanuel, and Tracy Holloway. Now I'll pass the screen, if you will, onto UCAR President Tony Busilaki to introduce this year's Distinguished Lecturer. Thank you, Tiffany, and good morning, good afternoon, everyone. I'd like to welcome you to today's Walter Orr Roberts lecture and also like to add my thanks to the Roberts family for their support of this series. I mean, it really is a great personal and professional privilege to introduce today's Walter Orr Roberts Lecturer, Professor Ravi Shankara from Colorado State University. Ravi is a university distinguished professor in the departments of chemistry and atmospheric science at CSU. And prior to that, he had a long distinguished career at NOAA's Earth System Research Laboratories in Boulder within the Chemical Sciences Division and in his previous life known as the Eronomy Lab. Ravi is a member of the United States National Academies of Science, a foreign member of the Royal Society of London, a fellow of the American Geophysical Union, and a fellow of the Royal Society of Chemistry, as well as the American Association for the Advancement of Science. Presently, Ravi chairs the Board of Atmospheric Sciences and Climate for the National Academies and the Science Advisory Panel for Climate Clean Air Coalition for UNEP. Ravi's interest has a world-renowned recognition, recognized for his expertise in atmospheric chemistry as it pertains to ozone depletion, climate change, air quality. I had the privilege of working with Ravi within the World Climate Research Program and it really is a distinct pleasure to now introduce today's speaker, Professor Ravi Shankara. Ravi, over to you, please. For some reason, I cannot seem to turn on my video, okay, there it says, perfect. Thank you, Tony, for those very kind words. It's really greatly appreciated. It's really an honor to give this lecture. I didn't know Walter Roberts, but I did know his trail, which I could see from a house in Boulder and walked on it many times, but I knew his reputation. And also it's humbling to be given this lecture, knowing people like Warren Washington, Susan Solomon, Kerry Emanuel, Jim Hansen, just to name a few who are previous speakers. It's really humbling. Thank you. As Tony noted, I spent roughly 30 years in NOAA and I'm going to start sharing my screen if I could. We tried this all out before, but it just doesn't want to work for me. Can you all see the screen now? Yes, that's perfect. Okay, thank you. Technology, technology. So anyway, I spent 30 years at NOAA and I've been at Colorado State University and I should acknowledge the contributions of the funding from NOAA, Colorado State, and also NASA. If NASA is listening, you got the best bargain for your grants. Okay, before I go further, I just want to take a second to note the passing of Mario Molina, a dear friend and colleague and an absolutely amazing scientist who many of us have known for a long time. I've known him for more than 40 years. He passed away last week and he's a real shocker for all of us. Okay, now turning to the topic at hand, all of you know that climate change is an existential threat, at least many of you assume that you know it. The reason it is an existential threat is because climate is being changed by human activities primarily through the emission of greenhouse gases. What this picture on the left shows is the way the concentrations of carbon dioxide and nitrous oxide and methane, which is on this scale, were as a function of the last 2,000 years. And as you can see, it was pretty constant and then it started going up with human activities. And the one shown here is for CO2 over the last 50, 60 years, the famous Keeling curve with a shout out to NOAA, with this enormous amount of work in making this possible, clearly CO2 is going up and up and we have already passed 400 parts per million, we are approaching not too far from being about twice what it was in the coming decades. But less known but important is the human activities are also creating aerosol particles. Aerosols are little particles suspended in air and they are also responsible for various things in the earth's atmosphere. So just to get you familiarize yourself to aerosols, incidentally we call it particulate matter when it comes to health and aerosols when we come to climate change. It actually has a role in both human health and climate change. These are very small particles. If you were to pull out one of your hair, I can't afford to do it, I don't have much. But if you did, you could see the dimension of your hair compared to the size of those particles. These are very, very tiny particles. And these particles, depending on their size, when you breathe it, it goes into your lungs and the size determines how far, how deep it gets into your lungs and it has very bad health effects. I'll show you in a few minutes. In addition, these same particles also affect climate change and actually in a way these particles have lessened climate change over the last few decades from going back. Now the key difference between greenhouse gases and aerosols is something we really need to note. The greenhouse gases in general are long lived in the atmosphere. If you put them there, they stay there for a while. While aerosols live for a very short time, maybe a couple of weeks. Because they're long lived, they accumulate in the atmosphere, the greenhouse gases. But because the aerosols go away, they do not accumulate in the atmosphere. The greenhouse gases absorb outgoing infrared radiation that is like a blanket that prevent heat from escaping. While the aerosols actually affect the incoming solar radiation, sunlight, the absorbent scattered incoming light. Greenhouse gases generally do not directly influence health. But aerosols do. Of course, greenhouse gases have indirect effects. When you change climate, it can affect health. What I'm going to talk about here mostly is about direct health effects. And also you can kind of think of this as I'm going to use this term called premature deaths. It's a proxy for health effects. There are other things that happen in addition to death that are important. At this point, I should take a second to kind of explain the big difference of this lifetime. Think of it the following way. Because Peter and Paul both had the same salary, they have a bank account, and except Peter doesn't spend his money at all. He saves it a lot, and the Paul on the other hand keeps spending a lot of it. So you can imagine the bank balance of Peter is going to be much larger than that of Paul. And what matters is if you're thinking about the effect it has, Peter will have more in the bank than Paul, and that actually has an effect on climate and various things. So that's the big difference between greenhouse gases and aerosols. Greenhouse gases are like Peter, aerosols are like Paul. Before I go further, I just want to acknowledge that I've been blessed with working with amazing scientists throughout my career. The talks I'm giving today are really based on the work of Daniel Murphy, who is at NOAA in what is now called Chemical Sciences Laboratory. He's an amazing scientist, and also Liji David at Colorado State University, who did most of the work on the air quality. Along with my colleague at Atmospheric Sciences, Jeff Pierce, and Chandra Venkatraman from IIT Bombay in India, along with Jack Kudros and a few others who are very helpful. The kind of stuff I'm talking about are actually in four papers that are listed below. Just a request, one of the papers that Ravishankar et al. is in press, so please don't blog about it. There's an embargo on the paper for a couple more weeks. The reason I'm showing this is because these are the building blocks, but I don't want to spend time on the building blocks. I want to tell you a story. I want to paint you a picture. I want to show you the little duck there rather than the individual bricks. So let's get started. Just so that we're all on the same page, oh, also I meant to tell you, I know there are a lot of experts at Atmospheric Sciences listening to this. My apologies up front, because I'm going to simplify things, and I might not put all the caveats I need to. So please bear with me. You all know what greenhouse effect is, hopefully. Essentially, this is the greenhouse. In the Earth's atmosphere, the greenhouse effect is formed by the greenhouse gases. That's why they're called greenhouse gases represented by these blue dots on the left. So when the sunlight comes in and warms the Earth's surface, the heat would be escaping to space, but these blue dots, the greenhouse gases, prevent some of that escaping and then essentially leads to the warming. Of course, eventually the heat does escape, but leaves the Earth warmer. So that's the greenhouse effect. Now, that is something that we are known, so the first thing you should know is the greenhouse effect essentially warms the Earth, the planet. On the other hand, aerosols have a different effect, as I mentioned. They scatter and absorb incoming solar radiation. So they prevent light from getting down to the Earth, so that kind of cools in a way. But also they do one other amazing thing, and that is they change the properties of clouds in many ways. Therefore, the clouds are the things that you see are bright out there, and that eventually also scatter, reduce the amount of light that can get to the surface. So the overall effect of aerosols is to cool the Earth's planet. So it is this combination of warming and cooling that we're interested in. So anthropogenic aerosols have lessened the global warming, that's the key point. So to put it very simply, here is the greenhouse gases warming, aerosols cooling, and what the Earth feels is the net effect. I just wanted to point out all these quantities I'm talking about are under human control. And the greenhouse gas influence includes that caused by land use change, and also there are some other things. And the aerosols effect also, as I said, includes direct and indirect effects. The key message I want to get across is aerosols have actually masked the full impact of greenhouse gases. In other words, they kind of helped climate change or reduce the climate change. Okay. So let's ask a question. Who on this planet have contributed how much to climate change? I'm not going to do it by individual people, but we're going to do it by regions. Okay. So you can kind of think of it as to what this world is like. We're going to divide this world into nine regions. Those that are developed countries, those that are developing countries, those that are in transition, et cetera, and also the development patterns having similar patterns, development and economics, et cetera. So here's a picture of what I call the climate forcing, which really is for those who are fishing out, this is the radiative forcing in watts per meter square on the left axis. Please look at the bottom figure. What that shows is the contribution of the radiative forcing from nine regions of the world. North America, Western Europe, China, Russia and Eastern Europe, Pacific, Middle East and the Africa, Latin America, other Asia and Indian subcontinent. As you can see, North America, which is essentially US and Canada, are contributing more to greenhouse forcing than any others. So as Western Europe, they started long further back and this is what it looks like as a contribution. But along with the greenhouse gases, if you include the contribution of aerosol, the pattern looks different. Look at the top picture. Essentially until about 1960, the net contribution was not all that large and North America kind of broke out in the late 1960s to early 1970s, followed by Western Europe and China is barely breaking out and as you can see India still hasn't in the subcontinent. There are a couple of key reasons for this. The reason is that the aerosols kind of offset the forcing by the greenhouse gases such as CO2, but also just as important is that you cannot keep offsetting the effect of greenhouse gases. You have to add more and more and more aerosols if you have to do this and at some point you can't do it. So that's what those combination of reasons. So this accumulation in the atmosphere of the greenhouse gases and the effect of the aerosols is the cause of this pattern of behavior. I'm going to just do this a little bit. So this is same area to force in for the globe as a function of fear. What matters is not what's happening today but actually what has happened over time. So if you remember your high school calculus, the integration is the area under the curve. So essentially what we're doing is calculating the total amount of energy that has been retained or prevented from going out from the Earth's atmosphere. Actually a big chunk of it goes away in terms of radiating at a slightly higher temperature. So this is what we call a cumulative radiative forcing and that is the equation. I'm sorry for the equation. But think of it again as this bank account as I told you. What's in this bank depends on what's coming from various sources. In this particular case I'm noting greenhouse gases offsetting the effect of aerosols and also land use and land cover changes. And then there is radiation going out and essentially so this is what's retained. So this is a very important way of thinking about it, very simple way of thinking about it. How much energy is retained in the Earth's atmosphere. There are also a couple of other reasons for doing it. You can relate these things to some key things in the climate equations and you can calculate the delta T if you know the climate sensitivity factor but that's not the key point though. I just want to show this slide to tell you there's real physics behind it. But before I can tell you what this means, I want to just show you a few numbers of the magnitude of this thing. So just the total amount of energy, cumulative radiative forcing, that's the additional energy retained by the Earth. Between 1907 and 2020, that's the area under the curve is approximately three yotta jewels. This is a unit that you probably haven't heard of. One yotta jewel is like one times 10 to the 24 jewels. For chemists it is roughly like Avogadro's number and so you can actually see it's like a trillion trillion jewels of energy. It's a lot of energy. So the total energy from the Sun we receive at Earth's surface every year is roughly two and a half yotta jewels. So over the last 110 years because of the greenhouse gases, essentially what has happened is only about one percent of the energy. Just to compare that with something else we know, the total amount of energy consumed on Earth in one year, the electrical energy is 0.0006 yotta jewels, which is roughly 0.02 percent of what comes from the Sun. Okay, with this background, let's do the blame game if you want to call it or the credit game, what are the contributions of different regions and different countries? So what is plotted here is this cumulative radiative forcing and to nine regions, North America, Western Europe, Russia and Eastern Europe, China, Indian subcontinent, other Asia, Middle East Asia, Latin America and the Pacific, there are a whole bunch of different bars. Let's look at the dark areas here. What these are are the contributions to date from the emissions, assuming nothing else is added after today. We actually stopped it in 2017, but it's today for all practical purposes. But even if you stop it today, nothing else you don't emit it. By 2100, this is the contribution. This is the legacy of these emissions is that it goes so far up. This is something that Susan Solomon in a PNAS paper pointed out a few years ago. And if you include the land cover, land use land cover, the picture changes somewhat and those are shown here. So you can see it for all these different countries that you can see today Indian subcontinent and even China haven't contributed as much as North America or Europe. Europe actually did almost all the land cover land use land cover a long time ago. So they don't get much in here. So you can see the pattern here. So the current contributions include the past emissions, the legacy of it and the developing countries have contributed minimally to climate change to date. And a large fraction of the greenhouse gas offset for aerosols does the particulate matter pollution is what's causing part of this. You can actually do it even simpler. Let's divide the world into the haves and the have nots, the OECD countries which are essentially the developing countries, developed countries, which is North America and Western Europe for all practical purposes. And then there are economies in transition, the countries that were communist countries that are transitioning their economies. And then there are of course the rest of the world. If you look at the contribution, you'll see that the developed countries have contributed roughly the same amount as the rest of the world. Okay. And if you then do it per capita or per billion people, this is the contribution of OECD countries compared to the rest of the world. So the bottom line message is the developed countries have contributed more to climate change to date and up to 2100 than the rest of the world. Okay. Of course, they have in the process gained a lot of wealth and a lot of other things that go with it, but that's a different issue. Okay. Now I have to show this just for completeness. So looking ahead, what could happen? And this is a kind of couple of scenarios. Again, the same kind of numbers except the scale has changed. This is the additional contribution shown here in the hatched area. For two different scenarios, one is called RCP 8.5, which is essentially business as usual. The other one is RCP 2.6, which is roughly, please don't argue with me, is roughly Paris Accord. So even if you did all things you could do, it's still going to get worse by 2100. Again, even in this scenario, the thing you notice is the largest contributions are from Canada, Western Europe, and China gets to be a big player if you go through RCP 8.5. Subcontinent is still kind of small and you can see the contributions of others. I know that what I've showed you is this energy thing that is not necessarily directly translated into the consequences of climate change. Big things such as sea level rise are related to exactly what I've showed you. But there could be other things that are much more different, shifts in precipitation and things of that nature that are much more complex. So this does not capture the entire impact of climate change. It's a way of kind of measuring roughly what are the contributions to climate change, especially the globally average temperature change and also for things such as sea level rise, etc. So the bottom line, what I've told you is it's not just carbon dioxide. Climate change contribution of different countries depend on the combination of greenhouse gas emissions, aerosols emissions, and land use and land cover changes. Climate impact of aerosols and greenhouse gases are not exactly the same. There are issues, some things we could talk about later maybe. But please, please do not forget the legacy of emissions. What we have done in the past is going to affect us today. And what we are doing today is going to affect what's going to happen in the future. In the long run, with a continued CO2 emission, you just cannot make up, offset the CO2 emissions by keeping freezing the aerosol pollution, you just, you can't do it. That's an interesting point. Okay, now let me just turn to the other face of these aerosols. As I told you, they also affect human health. And now I'm going to pretty much focus on the human health as relate to the country. I know a little bit about India, where I was born and lived for almost 20 years. So let me go into that issue. Why is this PAM, this particulate matter bad for health? It does lots of bad things. This is not my expertise, I should just tell you up front. And if you inhale it, it affects all sorts of body functions. This is a picture I took from my colleagues, John Vokunsen, Jennifer Peale at CSU. Jennifer is an epidemiologist. And John Vokunsen is a health kind of environmental engineer. And this essentially summarizes, there are four major impacts of this. It affects, it does things like lung cancer, strokes, heart disease and COPD. So that's some of the four regions to think about. Now, of course, when you think of India, you think of this iconic picture. This is a picture of Taj Mahal. It is beautiful, isn't it? And look at how beautiful it looks in nice blue skies and sunlight. And this is not the way it looks like when most mortals like us go and take a picture. This is what it looks like. This is really a picture I took a few years ago. And the reason it looks like this is it's polluting. You can feel, smell, taste, breathe the pollution. And that's how the pollution levels are in many parts of India. So this has helped climate, but let's see what it does to the health. So if you want to think about it, let's look at a satellite's view of what it looks like for various countries. This is the United States on the left, China on the right. This is from Mizer. And this is India. This is what the satellite sees. Just for your reference, you can all take a deep breath. Most of you heard in Colorado, today you're breathing roughly about two and a half micrograms per cubic meter of aerosols, PM 2.5. At the same time, people in Delhi, people in Bangalore where I come from are breathing 10 times worse here, about 25. In Delhi, it's like 85 micrograms. In a city about 100 miles from Delhi called Featherabad, it is about 100 times worse than in Denver or Colorado. This is the kind of air people are breathing. Now let's see how it looks in other parts of the world. It was like bad in parts of America, too. This is a picture I took from this beautiful study from Meng et al. There is Landl, Martin, Michael Brower, Conclair, et cetera, which came out last year. It just shows you the amount of PM 2.5 over America, the United States, from 1985 to 2015. Indeed, North America has cleaned up its air, as you can see. It's really much cleaner. But over India, you can see it. This is the Indo-Gangetic Plain. What you see here is really pollution. This is clouds. These are the beautiful snow-covered mountains of Himalayas, but this is real. This is what's happening. So let's examine this a little bit more carefully. So what we have done is to take the satellite-derived information and convert this to what is at the surface where people actually breathe it. There are lots of little ways to do this. There are things you do when we use something called a GEOSCAM model that can relate measured satellite information to surface PM 2.5. That's what really matters. That's what people are breathing. What you can see, this color scale is very deceptive. It goes from about 0 to 200. And 100 looks greenish. It doesn't mean it's good. It's bad. It has to be deep blue for it to be okay. And India sees deep blue pretty much during the monsoon season. And of course, this interganetic plane is off-chart, so to speak. So as you can see, most of this part of India is based in pollution almost all year round. So if you could analyze this information, what you see is that there are various contributors to this. And this is, we divided India again into a few different regions and looked at where it looks. Clearly interganetic plane is the biggest and followed by central India and not too far behind the South India. And the cleanest part, of course, is the northern India with the mountains, etc. Okay. There are two key things I want you to note. The anthropogenic aerosols still dominate over India. It's not just dust. And dust is not just natural dust. It's really suspended dust. It's actually something under human control. Organic aerosols are important, but they are not the dominant part of the aerosols over India based on the emission inventory we have today. Okay. So what does this do for health? So we can actually calculate how many people, what is the premature mortality due to this level of pollution over India? And what we calculate for the few different causes, heart attacks, stroke, COPD and lung cancer in the total is shown for all the different parts of India. Also, these scales are not the same. So it's going to deceptive this. This is about 5,000. This is 3,000 up here. It's only 500. Okay. So when you add them all up, this is what it looks like. And if you just sum them all up, we calculated that roughly 1.4 million premature mortality risk due to PM 2.5 exposure in India. And this is roughly comparable to what Kone et al. got in 2017. And there's also global burden of disease report. This is roughly comparable. I also meant to tell you there's a lot of uncertainties in these calculations. So don't take these numbers like really hard numbers, but it gives you qualitatively what happens. I mean, compared to America, this is like factors of 5 to 10 higher. Okay. Now, if you just look again at the different regions of India, what it looks like. This is a picture of the PM 2.5 annual average. And also the population in these areas. The interesting thing you notice right away is not only is the pollution high in the inorganic plane, so is the population. That means a lot more people breathing a lot more bad air, which shows up right here in the bottom figure. Okay. But then you can look at all these things and then calculate what fraction is, et cetera. So there are a couple of key messages that comes out from this. If you just reduce PM 2.5 by a small amount, you really don't gain all that much because the dose response functions are not linear, they're non-linear. You have to reduce it by a lot before you start getting huge gains. The economic costs of these are not just in terms of premature mortality, there are a lot of other things that happen. And also, just like this mentioned, this latency in all these things, it's just the long-term effects are not kind of included, it's hard to imagine or calculate. If you can put a picture of all the people who die prematurely, it would really show you the threat. I know when you start looking that kind of cracks and figures, we forget there are people behind those things. And mortality is not the only impact as I told you. So this is a pretty big issue in India. So if you were to then very quickly ask yourself, where is it and what does it look like in India? Honestly, once you normalize it for the population, the mortality is not all that different across India. This is kind of North India being almost the lowest, about roughly 700 people per million compared to maybe about 920 or something for IGP. But they're all roughly the same. As I said, the US would be way down here somewhere. Now, this is too complicated. So I just want to tell you, it's not just that people in one region are being affected by what's happening in that region. It actually gets transported, and as you can see in the picture before, it really goes from place to place. So the simplest message I want to get across very quickly here is, if you want to look at the contribution of the endogenetic plane emissions on the premature mortality, it's roughly about 420,000 people per year, about 0.4 million. But the same emissions affect roughly another 100,000 people elsewhere, away from endogenetic plane. Similar things happen from emissions in central India and a few other parts of India. So it's an issue that is coming up more and more, that the locals cannot necessarily control their own air quality. It actually is determined by what happens around us, and transportation, transport of this pollution is not a negligible problem. So if India were to plan something, it really should be planning a pan-India regulatory issue. Now, I was actually raised in a village for 10 years, and it has always demanded me that India is mostly what we call a non-urban country, and we usually associate pollution with urban regions. In fact, we usually call it urban air pollution. And it's also incidentally all outdoor air pollution I talked about so far. But let's ask ourselves, how does it change if you go from urban to non-urban regions? The reason I'm calling it non-urban is there are some interesting differences in the way populations are distributed in developed countries versus India. And the way we did this is to look at the night light, satellite data, and classified areas according to urban and non-urban regions. And then we can compare that with the census data from India, and it roughly agrees. It actually agrees quite well our classification. So we are parsed India now, not just into different regions, but between urban and non-urban regions. Okay? Then when you look at that and ask yourself, what is the pollution level in these things, you see an interesting picture. This is the paper that's going to come out in PNAS shortly, and this is the one I don't want you to blog about or share. As I said, there is an embargo. The top picture, this picture here, incidentally, this is essentially a satellite derived PM concentration, and it's weighted by exposure. In other words, you want to make sure that you count aerosols where people are, not where people aren't. Okay? So you kind of count for that. And then let's look at this picture here. For all of India, if you look at it, the population, a large population in the non-urban region is seeing these very high levels. Incidentally, it goes from zero to 225 micrograms per cubic meter. This is the number of millions of people. Also, I should tell you, this line here is the WHO standard for allowed PM2.5 exposure, and India standard is up here. The thing you notice is, the majority of the people are not, are well about the India standards, almost everybody is about WHO standards. But this is not just urban people who are feeling it. Look at this, this is the non-urban people who are feeling this large amount. Yes, what you see in the newspaper is this green line that goes way up here in the urban regions. But there's a lot of people in this region with this kind of pollution level. Then you can separate them out into the nine regions I talked about, six regions. And indeed, Indo-Gangetic Plain is what is making this big bump here. The Indo-Gangetic Plain has two things. It has major pollution, and the population in the Indo-Gangetic Plain is roughly 400 million. That's a big chunk of India. But so is Central India and Eastern India. Only when you get to Western India and South India do you see a non-negligible part meeting India's own standards. But even here, there's a very big chunk that do not meet Indian standards. So the bottom line message is, this is not just an urban problem. This is just the outdoor air pollution. Then if you start factoring in indoor air pollution, which we haven't done, I would argue that it's going to be much different. In fact, it'll be the same thing that the non-urban people are breathing just as much bad air as the urban people. And to put this again in quantitative terms, I'm comparing the annual mortality per million for the different regions between urban and non-urban. As you can see, to first approximation, they're almost all the same in all the regions. And it doesn't matter where you are in India, and that's what's happened. So again, you can just summarize this by looking at the mortality in millions, fraction, or annual mortality. As you can see, this is, if you look at per million people, urban and non-urban people in India are both breathing bad air just about equally and have the same effect. And just thing I want to just point out, it's not that all this bad air is coming from non-urban areas into non-urban areas. Non-urban areas are also creating their own pollution also. This is from an emission inventory by various sectors. And this is something you just want to note. But before I end, I want to just point out this is a movie we have seen before. I don't know if any of you can guess what the picture on the left here is. This was actually the one here. And this you can guess because this is Tithal Tower. And those of you who know about India can guess, this is India. This is the India Gate in Delhi. This was Danora, Pennsylvania in 1948. This is London in 1952. This is New Delhi, can't remember a year or two ago. And this is Paris a few years ago. This is actually interesting. The countries like America and Europe had very bad air pollution, but they have actually cleaned it up. That is one of the reasons why the climate contribution started going up from these countries. Air pollution is not new. But we learned a lot of lessons in cleaning this up. And it'll be really wonderful to apply those lessons to the countries where things are going bad. But of course, you need to include the local knowledge to make it usable. And also, I want to note, air quality problem is not only in developed countries. There's air quality problems in developed countries also, even now. So the key message is, air quality is not something you solve, but you manage. You have to learn to evolve, learn, manage, and be accountable as we go forward. So let me just kind of finish up with this slide again. I told you about the climate effect of this. The rich people, rich countries have contributed more per capita to climate change, to date, and in the future than the poor countries the rest of the world combined. And that's the point I made earlier. The health burden, on the other hand, is much more, much worse in countries like India. And here I show you the same health burden from PM 2.5 took from OECD report from 2020. Its factors are three to five, depending on the countries, less than in this country. So that's my tongue-in-cheek title for my talk. Are the people in developing countries paying with their lives to make climate better for everybody? With that, let me just summarize the key points I want to make is that developed countries have contributed more to climate change, to date, than developing countries. PM 2.5 pollution in developing countries have reduced climate change, but those countries are paying a price for it in bad health. Continued bad health is not an option in the long run. Legacy is important. It's important for so many things, and it's important for climate change, and also for equality. Contribution to future is avoidable, or the contribution to the past, we don't know what to do with. We're stuck with it. There are implications to what I talked about for other things, going forward for developing countries with cleaner air without greenhouse gas emissions. And also about geoengineering and things of that nature, especially solar energy management. I didn't talk about it, but I just wanted to mention that up there. With that, I really thank you for your listening. I assume there's somebody listening. I have no idea. But also thank you to UCAR and NCAR for this opportunity to give the Roberts lecture. With that, I stop. Paul, should I stop sharing my screen at this point? Yeah, I think so, yeah, that's good. So thank you, Raleigh. Thanks so much. One of the phrases that Walt Roberts is famous for coining is science and support of society. And you really epitomize that in your lecture today, and thank you for that. And in that, you know, oftentimes climate change, greenhouse gases, atmospheric aerosols can be abstract. And you really brought it home to what the impact is on the individual and the populations in developing countries. And so I really appreciate you doing that. And then also you demonstrated for us today that, you know, air quality has been managed. Can be managed. And by extrapolation, that can also be applied to the greenhouse gas problem as well. And so, you know, I think you demonstrated as severe as a problem is that there is optimism to be found if we have the will around the world to manage it. We have a series of comments and questions of coming in for those that are watching the livestream. Please scroll down and submit your questions to Ravi. And I'm going to turn it over to Ravi to basically take them as they come in. Ravi, over to you if you can see them. One second, please, because I'm not able to get rid of my screen sharing. If not, I can read them for you. OK. Oh, I see. I can just look at my other screen and OK. Thank you. Thank you for the first question. I'm not sure what LMICs are, but yes, there are other things. Also, we have started accounting for things like that, including diabetes in more recent papers. Thank you. That's the first question. But Steven Schwander, I think that's the done. Yes, the air pollution does shift the monsoon. There is some things like that that are really important. And I mentioned what I showed you is kind of important for kind of global effects. And there are other intricate effects. Also, there are issues about black carbon heating versus cooling and the whole host of issues. The aerosol precipitation issues are very big one. And yes, the shift in monsoons, even by a few degrees, could have a huge impact on countries like India. Thank you for pointing that out. Yes, say North America cleaned the air pollution. Yes, it actually cleaned the air pollution in a couple of ways. The regulations really did help. The U.S. has greatly reduced SO2 emissions and to some extent some NOx emissions. So that 35, the sulfate emission reduction is a very important issue. Yes, America also shifted production to elsewhere. But you know, the manufacturing in the U.S. has now gone down. It has been automated, so more and more. So in terms of production, the cleaning up was very important. Again, as Tony emphasized again, we really can't clean up our air. So that is something to think about. Thank you. Thank you for the next comment. I don't think... Oh, Shukla, thank you for listening. Oh, great. Shukla just gave me a ground-based verification of, you know, he has a village in the Gangetic plain near Kanpur, and he is telling me the pollution there is pretty bad. And he got a better idea of why it is. Thank you, Shukla. Incidentally, he does a great amount of wonderful work there in supporting the college, if anybody is interested. Any other questions? So probably, you know, in the people that are watching, we have a wide range of people from, you know, early career, mid-career, late-career, just people within the community, you know, sincerely interested in our science. For the early-career scientists, you know, any advice to the early-career scientists in terms of, you know, career trajectories and what you see as the emerging, pressing problems from your perspective. Thank you, Tony. That's another way of, Tony, saying, I'm an old man. Yes, which I am. Me too. Yeah, my life, my trajectory was kind of partly accidental and partly good luck. I got into atmospheric chemistry because I heard Sherry Rowland's talk. That was the first time I saw a picture of Maurya Molina, actually. And then I had the fortunate chance to work in amazing places like George Tech and NOAA and now at CSU and having amazing scientists, colleagues. The thing that I found was what I would say is I kind of have followed what I would call the pastures quadrant in science. That is use-inspired research. It is not necessarily user-inspired, it's use-inspired research, which essentially runs the gambit of doing the very fundamental things like doing laboratory studies and various things like that to kind of trying to take that information to a usable form and make it usable by the society and policymakers, et cetera. There's an enormous amount of joy in doing that, the last part. And also one thing I'll tell you, if I were to do my career all over again, I would take some key social science classes. It's so important to have social sciences in our work because if you do socially relevant work, we really need to understand social sciences and they should be coming in at the beginning of research projects. Thank you. Thank you, thank you, Ravi. And the last point is, you know, my experiences like over the last 10 years, we've seen kind of a shift in the students being much more socially conscious and actually doing dual group degrees, taking courses in social science. And, you know, the work we're doing, it is a continuum. It's not basic research onto itself, it's not applied research onto itself. It's all the way and it's not either or. And we now have some more questions coming in, so I'll turn it back over to you. The residential contribution in non-urban areas are higher because the population there is higher. India is still mostly an urban region. I just showed you the raw total amount of emissions. Is India planning to shift renewable energy? I hope so. Yes, at the same time, they did build some coal burning power plants in the eastern part of India. And there's also a huge power plant being built on the border with Bangladesh. There's a whole issue of, you know, just because you move the power plant across a border doesn't mean the emissions stop there. Yeah, that's a big issue. Yes. Does the use of renewable energy. It is a big, in my opinion, humble opinion, I'm not an expert in this. Renewable energy has a huge role in cleaning up North America. Cleaning up North America for the invisible CO2 pollution. That is continuing to, yes, it's not going up as much, but it's still going up. And it's not, yes, it may be this year the emissions have gone down a little bit. But you know the thing that you may not realize, actually, I had a slide on it. Even if you were to just kind of stop emitting today, our climate change is not going to go away. In fact, it's going to get worse for the first decade or so before it even stabilizes. There's the forcing and the change itself is going to go on for a long time. So yes, yes, there are lots of interesting reports about COVID and clean air. In fact, I have two of those papers on my desk for some other general I'm dealing with. India has seen it and lots of other areas have seen it. Again, it just shows you that indeed if you turn off air pollution, the things that make air pollution, air pollution goes away. There's a quick return. It really does help and help now. Yeah, so yes, what I would call this COVID has created a perturbation experiment for us. It's an unexpected perturbation which has shown what can happen. Thank you. Thank you. I don't know what to say. Yes, I'm reading this question, the global per person contribution to warming. It resonates like a privilege issue, benefits for some are at the cost of many others. I don't know if I look at it quite that way. I think I would look at it maybe more like a responsibility issue of taking responsibility for things that we have done in the past. There are so many other social issues like that. So I don't know, maybe I'll think of it more as a responsibility issue. Thank you for pointing that out. Yes, I actually had a slide. I kind of skipped because of time. How much of the pollution in India is coming from other countries? It's not zero, but it's not huge. And it also depends on which part of India you are in. The northwestern part of India does get a significant amount of pollution from elsewhere. And similarly, India transports a lot of pollution to Bangladesh. If I'm not into policy, but I would like to point out that Bangladesh is surrounded on three sites by India. And even the eastern part of India gets most of its pollution from the rest of India. Thank you. Oh, thank you. I don't know what else. I think this whole thing with COVID is a great opportunity for us to increase our knowledge and transmit that knowledge about the aerosols and the role in at least air quality. The thing about climate change is a little harder to see. But yeah, I need to think about it. The aerosols and the transmission and etc. due to the issue of COVID has really heightened people's people are much more receptive to this information. And I think we should take advantage of that. Thank you. Can carbon capture and I haven't seen very practical ways of capturing CO2. But if somebody were to come up with capturing CO2 and storing it, you know, more power to them. But you know, the thing that we have to remember is if you once you already emit CO2 into the atmosphere for you to process all the air that is in the atmosphere back through some processing plant, it takes a lot of energy. I once calculated this for a totally different thing. How much air is processed through all the thermal power plants? Okay, that takes roughly 10,000 years. Okay, I think those are the questions so far. All right, all right, Robbie, we're at seven minutes past the bottom of the hour. Let me just thank you once again for a very stimulating talk. You really was thought provoking in a very positive sense, again, bringing it home to us as what individuals are and really appreciate your leadership on this particular topic. And as I said before, your talk really did epitomize science in support of society. And I'd like to once again in closing, thank everybody for watching this morning and afternoon, the Roberts family for their support, Tiffany Formant and UCAR Center for Scientific Education. And again, please join me in a virtual applause to Robbie. And Robbie, I do look forward to thanking you personally on the other side of COVID. So thank you once again. Thank you very much. Bye, y'all.