Erin: Hello, welcome to Earth Science and You. I'm your cohost Erin McKinley, talking to you live from Goddard Space Flight Center in Maryland. I'd like to welcome my host/co-host for the day sharing the duties of hosting today. We have the Assistant Director of Science, Dr. Michelle Thaller. Welcome, Michelle!

Michelle: Well, thanks, Erin. It's great to be here. Yes, this is Earth Science Week 2011 and all week long we're learning from NASA's scientists about how Earth Science, as you might expect, is literally all around us, and in order to find out what NASA's doing to celebrate this really important week, we really encourage you to go to the website that has more information about all the different events and the webcast, lots of different things and that's climate.nasa.gov/esw for Earth Science Week 2011. So once again it's: climate.nasa.gov/esw2011

Erin: Throughout today's program you'll be able to submit questions live to us that we'll be able to ask our guest in studio and you'll be able to submit those via email. We'll be showing the email address throughout today's program, here it is for the first time, it is: DLinfochannel@gmail.com. Once again:

DLinfochannel@gmail.com. I'm looking forward to hearing all of your fantastic questions, I'm sure Michelle is as well. And we have a terrific guest with us today, who is joining us today?

Michelle: Today actually, we have Dr. Waleed Abdalati, and Waleed is NASA's Chief Scientist and amazingly he is an also an Earth Scientist. Earth Science is his specialty, his passion and so we have exactly the right person to talk to us today about everything going on in Earth Science Week. So welcome, Waleed!

Waleed: Thank you. It's good to be here.

Michelle: So I guess, we'll start off with some questions. Now, Waleed, as we mentioned, you are an Earth Scientist, that's your career. What was the path that took you on that? How did you get involved in Earth Science?

Waleed: Boy, the path was really an interesting one. I started out as an engineer, I liked building things, designing things and as I was working in the engineering profession, I got... I was in the satellite business. I designed and analyzed space satellites that orbited the Earth. I got more interested in what these things were seeing than actually building them, so I decided to go back to graduate school, focus my studies more in the Earth Sciences and that science focus in graduate school coupled with engineering focus in the undergraduate curriculum led me to the use of space satellites to understand how and why the Earth is changing.

Michelle: And what does the NASA chief scientist do? What is that job description? [laughter]

Waleed: It's a great job because I get to be at the forefront of NASA science discoveries, it's not that I make them but I observe them, I interact with the community that does make them. But my main functions are: 1) to serve as an advisor to the NASA administrator: he has a lot of things to think about: with human spaceflight, with technology, with science in all different areas among other things, so he wanted a person who could handle the science for him and give him a perspective to help him formulate and make his own decisions. And another thing I do is I serve as a voice of science both within NASA, representing the science community to the highest levels of NASA saying, "These are the things that are important scientifically, these are the things we ought to be going after," but also outside NASA to Congress to the White House, to go forward and say, "This is important to the nation. This is important to society for these reasons..." and it's great being an Earth Scientist in that position, because as I told you earlier, Earth as my favorite planet and to be able to speak to how Earth Science fits into the broader NASA science portfolio is really a privilege and actually a heavy responsibility, so I try and do my best to do it well.

Michelle: Well, just like you said, I think, often times if you ask a child, what's their favorite planet, they'll say, “Jupiter" or they'll say "Saturn," but a lot of people don't seem to really internalize that Earth is a planet, it's part of this larger Solar System we find ourselves in, and a lot of people as well I think are surprised that NASA does so much Earth Science. So, tell us about some of the unique capabilities that NASA has to study our own planet.

Waleed: Sure, and I'd like to start by saying: to really understand the Earth: how it works, how it's changing, why it's changing, requires that you look at the Earth as a whole, as a system and that you look at the interacting components of that. You can't just look at the atmosphere; you can't just look at the ocean. You have to look at it all, how they interplay with each other and that requires stepping outside, observations from high above, watching the Earth unfold beneath us, watching the interaction of all of these elements. So, we have a fleet of satellites and we're trying to add to them as time goes on, that look at ocean salinity, that look at the temperatures of the waters, of the land, that look at the kinds of land cover, that look at how and why ice is changing: look at all these things and put them together to tell the story of the Earth.

Michelle: To me that am amazing, it is one of the most... things I am most proud about at NASA: is just the breadth of Earth Science we do and all the different things that we study. Now, your specialty is ice. A lot of times they call it the cryosphere: the icy sphere of our planet, and you're going to talk to us today, a little bit, about the observations we're making of changes in the ice as well.

Waleed: Yeah, absolutely, and ice is, a lot of people do not realize this because it's so far away, they may wonder, how can what's up there affect what happens here -- but ice is a fundamental element of the Earth's system, it helps to keep the planet cold. I think you'll see some video in a minute - but it helps keep the planet cold by reflecting the sunlight that comes on, if you look at this video you see the ice is white, that reflects sunlight, keeps the planet cool. The other thing it does, is it provides a barrier between the heat of the ocean and the atmosphere above which affects atmospheric movement of air and weather patterns, affects the movement of ocean water and climate patterns and then the last piece of this, which is what I study, is the Greenland ice sheet, the Canadian ice caps: land ice, which as it starts to melt, has the potential to raise sea level quite substantially and affect coastal areas. So we use instruments to determine how much the ice is growing or shrinking. We use instruments to detect how much salt the sea ice is putting into the ocean or taking up from the ocean as it forms. We use instruments that look at the temperature of the ice, you know: Is it cold ice? Is it warm ice? How thick is that sea ice? How well does insulate the ocean from the atmosphere above? All of these things affect climate and all of these things affect the environment in which we live.

Michelle: Now, I remember a NASA press release from a just a few weeks ago that we just passed the minimum of the northern sea ice just a couple weeks ago and while it wasn't actually the record for the smallest extent, it was close. What was this year's ice like?

Waleed: Yeah, this year's ice was the second lowest in the satellite record, which goes back to 1979 and I stress with people: we shouldn't look at individual events; you can't look at extreme events and make a conclusion about that. But because of the extent of the satellite record we've had the opportunity to look at the trend, the way the ice is changing, and it's shrinking quite substantially, this thin veneer, this blanket of ice that covers the Arctic Ocean, it's shrinking substantially to the point where it may actually disappear in the next couple of decades, which is something human civilization hasn't experienced. Now, that doesn't mean awful things are going to happen, it means the environment will be different and this is where the other satellites come into play, to understand, as that ice shrinks what's happening to sea level? What's happening to coastal areas? What's happening to the weather patterns, the climate patterns? We have a mission that's going to be launched later this month that's going to look at just those kinds of things: weather and climate. So by putting all these pieces together we get a story of how the Earth is changing.

Michelle: One of the more unique spacecraft, actually two spacecraft that NASA has, is GRACE: the Gravity Recovery And Climate Experiment.

Waleed: Love GRACE.

Michelle: Now, these are two satellites that are orbiting the Earth and measuring, just through gravity, how much different...like, for example, ice levels are changing in Greenland and I believe for the last, almost a decade now, Greenland has been losing hundred 150 billion tons a year, or thereabouts.

Waleed: Huge amounts, the equivalent of Lake Mead in the Western United States. GRACE is a phenomenal satellite, or pair of satellites, actually and it really shows... this is why my background is so well suited to this kind of thing because I do science, I do engineering and it really shows the combination of the two. So, the two satellites fly one behind the other and as they come over a mass, like Greenland, Antarctica, or something, the first satellite will speed up a little bit, because the gravity's stronger there, and the second one will stay where it is until it passes Greenland, this one will slow down, this one will speed up and the separation here will be the same as the separation there, but the distance between the two -- the increase in separation tells us how massive the ice is below. It's kind of like two unattached cars on a roller coaster, if one follows the other and you get into a well: the first one will sort of separate from the second one, but the second one will eventually catch up and the deeper that well, the steeper that well, the more they'll separate, it's the same thing but with gravity. So by doing this year after year after year we can watch the ice grow or shrink and figure out how much it's dumping into the oceans and what that means for coastal sea level.

Erin: That's all fascinating information. We're already getting questions from students viewing our webcast today, all about ice. Are you ready for the first one?

Waleed: I'm ready, I love ice.

Erin: All right. Eric from Maryland asks, "If the sea ice melts wouldn't this be good for ships?"

Waleed: Yeah, this is actually a great point because there is opportunity in changes if you're prepared for them and you can capitalize on them. If the sea ice melts it does open up the Arctic Ocean to exploration, to navigation, you can cut down transit times quite substantially by not having to go down through the Panama Canal or whatever to get from one high latitude place to another across the Arctic. So, absolutely, there are benefits. There are also downsides: the United States, for example, would have a more vulnerable border, because it's accessible, more readily accessible by ships. The bigger concern, I can't call it a downside because we don't know the outcome yet, but the bigger concern is: what does that do to climate around the world? Humans have never known an environment without ice in the Arctic. If it goes away, it's quite conceivable that the kinds of crops that grow in Kansas won't grow anymore. Areas that have a certain climate ripe for farming may not be anymore; areas that are dry may become wet. Some areas will see benefits; some will see challenges associated with that kind of change. So for us at NASA, the real challenge is trying to figure out what's coming, whatever it is and why ever it is, so that we're in a position to capitalize where we can: make the most of the change, but also minimize the negative impacts that may follow.

Erin: Excellent. We have another question leading into the effects, causes and effects of various weather changes. We have Lisa from Maryland ask, "We noticed we are in the midst of a La Niña, what are some of the recent theories to the triggers behind El Niño and La Niña events?"

Waleed: Boy, that is a very complicated question. It has a lot...and Oceanography is not my particular area of expertise, but it's really driven by the wind patterns and the circulation patterns off of South America. This is why they're given Spanish names. So there are triggers or switches, the way sort of the normal state is: wind blows up the coast of South America, up the west coast of South America and then veers westerly -- you know, it’s because the Earth is spinning, there's a lot of physics behind that, but it wants to turn to the left as it's coming up the coast of South America. That's the normal state of affairs, but sometimes we get sort of stuck in another mode where that is suppressed, where the wind does not go up the coast of South America and I should say the wind and the ocean circulation, where it goes a little slower or it starts to flow eastward rather than westward and the ocean, which is used to a certain state set up by those circulation patterns, is in a different state: is in a new state. So the climate that begins with that original circulation pattern, and the energy that moves with it is changed, and this is what El Niño is. We switch into this new state and then we switch back, and it tends to oscillate, you know, it varies over 4 years, 6 years, 8 years. There's nothing regular about it, but there tends to be two states that dominate.

Erin: Very Interesting. We have one final question; it's actually about hurricanes. Are you ready for hurricanes?

Waleed: Ready for hurricanes!

Erin: All right. This comes from Gabriel in the Dominican Republic. He asks, "How can the Saharan dust storms coming off of Africa affect hurricanes in our hemisphere?"

Waleed: That's a great question and shows a lot of insight and it starts with what it takes to make rain. It takes water vapor in the atmosphere, that's is pretty obvious, pretty intuitive, I should say, but also takes particles around which the water vapor can condense. Water doesn't just turn to liquid -- well it does if the temperature gets low enough, it will turn to liquid by itself, but it happens much more efficiently in the atmosphere when there are particles that the water vapor molecules can latch onto and once they make that contact they turn to a liquid, they condense much more readily. So, the stronger the dust storms, the more particles that are blowing across the Atlantic Ocean, the easier it is for that water vapor to become rain, to become liquid, and that is the connection. What I like about that question is it really highlights that there are connections that you would not think, you would not think that storms in the Gulf of Mexico are intimately linked to how dry it is and how strong the winds are over the Saharan Desert, but they are and that's the way the Earth works. I think that's actually good lead-in into the next animation, which is hurricane formation. We watch these from space and we sort of stack information, what you're looking at now is just visible imagery and we can watch the flow of a hurricane. I'm not sure if this is Wilma, I think this is Wilma, it might be - it actually looks like Katrina.

Michelle: Looks like Katrina, yeah.

Waleed: The flow of the hurricane...Just visually by watching the clouds, we see where it goes. Now, when we couple that with sea surface temperature, which is what you see here, reds and blues and such, you see that as the hurricane moves across a warm area, which is red, which will come back in a second, it leaves behind it a blue area, this is precipitation. So I'll...we'll wait till we loop through. This is the visible again. You can go back and run that. The hurricane enters a warm area that looks red but leaves behind it a blue area, which means that energy has transferred from the ocean, because the blue is cold, into the hurricane and that's how hurricanes strengthen. So we add to that the precipitation information: so now we watch the trajectory of the hurricane, we watch its uptake of energy, as you're seeing here, and then we watch how much rain falls. We have instruments to can look at the rainfall which you're seeing here. The darker colors as it moves over Florida is increased precipitation. You can see that starting to fall and then what ultimately hits New Orleans. Take all that, and we start to really understand the physics of the hurricane: how they form, what controls the path they take, how they take up energy, how they deposit precipitation, and this really equips us to better understand what the next hurricanes may bring. If we understand the ocean conditions, the conditions the Sahara, we can start to predict when the hurricanes will form, how strong a season it will be, and ultimately where it will go and that makes a huge difference. Being off by 50 miles - from a very populated area to an unpopulated area makes a tremendous difference on how you respond to that, what do you evacuate, what don't you evacuate. Because this all of these cost money, all of these affect lives in significant ways. So these data really help us understand how to respond and prepare.

Michelle: Now, once a hurricane has actually formed, NASA observes them in a really interesting combination of ways, we've got have satellites, we have aircraft. Want to talk a little about how we sort of pick apart how hurricane works?

Waleed: Sure. You just saw a sequence of satellite images that together tell a story about the hurricanes but we also as well as NOAA, fly right into these things. [laughter] I've never been on one of those flights, but I'm told they're pretty dramatic...

Michelle: I'm pretty sure I don't, want to actually!

Waleed: ...and then you relax when you're in the eye, you know it's very calm in the eye of a hurricane. So, we take that, we take ground-based radar: we're sending out signals, out into the ocean and measures the energy that comes back. You've all seen these Doppler radar maps on the Weather Channel or on your local forecast. So we have ground-based instruments that look across the water to see how hard it's raining and where it's raining and we have satellites that look at the banding and cloud structure, we have satellites that look at the temperatures, we have satellites that look at the rainfall, we have instrumented aircraft that fly right into these things and figure out how fast wind is blowing. We also have satellites that can look at wind speeds. Put that all together and you really get a sense of the structure of a hurricane and every hurricane is a new bit of information that helps us understand the next ones better.

Michelle: I don't know if we have any questions on hurricanes?

Erin: Not yet, but remember, you can submit questions live to us via email and that email address is DLinfochannel@gmail.com. You can see it right below us: DLinfochannel@gmail.com.

Michelle: So obviously, with something like a hurricane, one of the things that we're most concerned about is the human impact, like you said, it costs money to evacuate, there's a safety issue. There's also the idea of what humans are doing to the Earth's climate: how the climate affects us, how we affect it, and then how life is sort of tied up in this equation of how the Earth works.

Waleed: Well, life is a fundamental element of the Earth system, the Earth functions in large part the way it does because of the life that's on Earth, and I don't just mean people, and I don't just mean urban areas, or human civilization: I mean all aspects of life and if you look at something like vegetation, it is closely coupled with the amount of carbon dioxide that's in the atmosphere which affects global temperatures -- you know: the more the CO2, the more carbon dioxide, the more heat is trapped in the atmosphere, the warmer things get -- we have a strong interest for example, in how, in what the interaction between the atmosphere and vegetation on the Earth's surface is and if you watch the vegetation over time and you at the same, time track the carbon dioxide levels in one place, there's-- Mauna Loa, a mountain in Hawai'i, a volcano in Hawai'i, where we've got an extensive carbon dioxide record. If you just watch the seasonal change in that carbon dioxide record: what you see is that during northern hemisphere spring, it's up here now - you see the - in the northern hemisphere spring the carbon dioxide levels go down and in the northern hemisphere winter they go up and this is what you're looking at. The white line is carbon dioxide at Mauna Loa and if you just sort of look through the line and let your eye kind of keep track of what the white line is doing and look at the vegetation in the background, and it's not just the vegetation on land, but it's biomass, what we call it: life in the ocean. Plant life in the ocean, you can see that the greener that picture gets - as the picture gets greener, the carbon dioxide in that line goes down; as the picture gets less green, like now, the carbon dioxide is going up and this is showing you how plant life, how flora, are taking up carbon dioxide at the very present, and this is a relationship that shapes the environment we live in, just as humans have an impact, both positive and negative on the environment we live in, vegetation has an impact, animals have an impact, all life on Earth has some kind of relationship with the environment in which we live and part of what we're trying to do at NASA is understand that relationship because we affect our environment and our environment affects and shapes us. So the better we can understand those relationships, the better position we will be as a nation, as a society, for success in the future, whatever lies ahead.

Erin: Excellent. I'm so glad you touched on that point, because we've been having a lot of questions come in on, "How can humans affect that relationship?” I'm glad you said that it is a relationship between animals, plants: everyone on our planet Earth. Thank you so much. We do have another question in, from Arty in Virginia, and this is a loaded question. He asks, "Various countries are investigating the makeup of Antarctic lakes buried by extremely thick ice. Can the space-based assets actually determine where these lakes are located? And whether there is indeed liquid water? And how does it do so?" I think we have a gifted student watching us today.

Waleed: [laughter] Yeah, that's great. It makes me glad that my expertise is ice; I don't think I'd be able to answer it if it weren't. We use space-based and air-based assets to detect the presence of these lakes, and whether there's water in them or not, and the way we do that is: Antarctica, it may have a couple of miles of ice of thickness but the surface is in some sense an indication of -- the geometry of the surface is an indication of the geometry that lies below. So when you have a depression that's filled with water at the bottom of Antarctica under a couple of miles of ice, you have a flat surface at the top of that lake, just like lakes you see on the surface of the Earth. That then makes the surface of the ice look flatter than the rest of the stuff around it. So, we look at low sun angles so we can see the really detailed topographic features of the ice and we find areas that are flat, just really, really flat compared to the surroundings. So that's the first indication that there might be a lake there. We also go over with measurement - with instruments that measure precisely the elevation, so we see roughness in the surface using - what we do is we fly a satellite that shoot lasers at the surface that measures the travel time of the laser pulse. We know the speed of light, so by measuring the time of the pulse we figure out how far the surface is from the satellite, we have GPS on the satellite to tell us where it is and from that we can tell the height of surface below. We take that information and when one of those satellites lies over a lake all of a sudden the graph of the roughness of the surface gets really smooth and then it gets rough again. We know there's something there, a very flat surface that really can only be water. With gravity instruments usually mounted on airplanes, we fly over these things and we measure the gravity. Now, ice is less dense than water, so what we see when we fly over a lake, even though it's below all that ice, is we see a gravity anomaly -- that little piece below the aircraft is denser than what's around it, so we know there's water there and the greater that density difference, the deeper that water must be. There's just more mass there, so we use these to find the lakes. Now, to understand what's...The last thing is radar. We have radar that looks through the ice, it penetrates the ice but it reflects off the water. So we can go over with radar and just see. We just look right through the ice and see these lakes. But to study what's in them, we have to drill and take samples and that's very complicated, because we don't want to introduce things to this pristine environment that could be millions of years old, for all we know. So there's a challenge there. But detecting them, understanding the characteristics is something that we can do from space, and the air and the ground.

Michelle: What are some of the larger issues? If you were to answer the question, "Why is NASA interested whether there is a lake underneath Antarctic ice?"

Waleed: We're interested in whether there's a lake under Antarctic ice because it tells us something about the history of our climate. It tells us something about how ice works. It tells us something about how geology works. What can make a lake form in this location? Well, some of it has to do with the pressure of the ice above, changes the melting point: you can form water at colder temperatures than you can at the surface. But it really comes down to fundamental exploration: how does our planet work? And what does that ultimately mean? You know, and it turns out these lakes are very active; they flow through channels, or rivers. Underneath all this ice there's a very active network where one lake can drain and flow into another lake somewhere else and we see this in the altimetry, in the elevation data. Where for years this place will be this high, this place will be this high and then all of a sudden they do that and we know the water has gone from one to another. Why is there a network underneath there? Well what does that tell us about the evolution of our planet? What does it tell us about what might be coming if this is an increasing phenomenon? If the energy from inside the Earth is making it to the bottom of the ice and causing more melting, what does that mean for how stable the ice sheets are? You know, all of these are just questions about our environment and some of it is sort of practical with an outcome: What are the implications for sea level rise? And some of it is just simple scientific discovery and what I love about Earth Science at NASA is we're just immersed in both. You know, I say science to inspire, and science to serve and we do it in spades in both of those areas.

Michelle: There's also this sort of this added wonderful part about studying icy moons around other planets. You know, there's the moon Europa around Jupiter which may have water underneath ice. I know there's a lot of planetary scientists that are very interested about how you might study under ice water to begin with.

Waleed: Yeah, and I think the main... the main tool is radar, I mentioned we have radar that can look through ice and do reflections off of water so we can sort of see what's beneath. But these places are far away, they're very cold, they're farther from the Sun, so the energy you need, you can't just, like Earth, rely entirely on solar panels, so exploring these far-off places really presents very difficult challenges, but that again, that appeals to the engineer in me you know? And human ingenuity to get there, to do that because it's hard and it's fascinating and it's something - you know, it's the stuff dreams are made of. When you're a child, what do you do? You look at planets, you look at stars and you wonder and I think, and I would encourage anyone who's watching, hang onto that. Let that guide you as you pursue whatever it is that you pursue as you go to college and take on jobs, because it's that wonder, it's that sense of motivation, it's that, "This is really cool!" element that will make you good at what you do. You know, if you're just laboring, "Oh, I did this because I thought I could make some money, you know..." you won't be exceptional at what you do. But if you're energized by it, if you're stimulated by the thought of an ice ocean on Europa, I think the possibilities for you and your careers and what you choose to do with yourselves are limitless. They're limited only by your energy so fuel that energy and you can go far.

Michelle: I would definitely have to agree with that.

Erin: Absolutely! [laughter] We have one more question...

Waleed: Sure!

Erin: And before we get that question I'm going to remind you all again of that e-mail address, it is DLinfochannel@gmail.com. Keep those questions coming, I know we've had some fantastic questions so far. We have a question about the earthquake that we all experienced here in the area not too long ago and we have a question: "Can we expect that to happen again?” This is from JoAnn in Maryland.

Waleed: Um...Well, I believe in never saying never. [laughter] So... when an earthquake happens once, what that's telling you is that there's what's called -- well, there are stresses, there are pressures in the earth of crust pressing against itself or two elements rubbing against each other and eventually -- you know, if put your hands together, press and try to pull one toward you and the other one away, eventually you can make them slip, right? Or sometimes they can slip one over the other and so what that earthquake has told us is there is a stress field. There is that pressure in the vicinity that relieved itself, that when there is an earthquake, that's a release of that stress. What we don't know is, is it done? You know? Will in 10 years, 30 years, 100 years, those pressures build up again? They will build up again, but have another slip, another displacement like that? And we approach that actually, on the ground in populated areas: we put GPSs all over the place and you can measure the movement of the Earth and by measuring how one GPS moves away or toward another, we can infer the pressures that are building up. From space -- that’s great and populated areas -- in harder to get to areas from space we actually can use a sophisticated kind of radar that tells us in very, very precise detail what that strain field, it's called, but basically gives us clues to what those pressures are-- how hard things are pressing against each other, or how they're pulling apart, and we can map, sort of -- it's not that we can predict earthquakes, but we can map, kind of, high compression areas, we can map areas that are undergoing change and look at that. So I can't directly answer "Can we expect another one and if so, when?" We don't have the knowledge to do that: earthquakes are not that predictable. But what I can say is, we've got the tools to understand the processes, that someday may lead to that ability to protect, er, predict, excuse me, and it kind of comes back down to sometimes it is just about learning, just learning the physics and trying to understand it.

Erin: Terrific. I know you already touched on this before a few moments, but Earth Science can affect all of us in our everyday lives and you've talked about how we put GPS in populated areas to at least get a heads up on when earthquakes can affect our area. How else can Earth Science affect humans?

Waleed: Well, Earth Science, in the broadest sense, includes things like figuring out the weather. It's understanding the atmospheric processes that cause or create wind and rain and things like greenhouse warming, how much heat gets trapped in the atmosphere, so in that sense it's helpful. From a climate perspective...you know, there's value to knowing what next season will bring, what next year will bring, what next decade will bring. Maybe not knowing it exactly, but if you know an area's going to get drier or wetter, we can plan for that, we can prepare for that. If we know that sea levels are rising at a certain rate: it's very, very slow, but over 50 years, it's a lot. You know, it could be this much in 50 years, which in one year may not be a whole lot, but we can start to adapt our infrastructure: as roads and bridges need repair we can migrate them inward. You know: it's all about helping us plan and figure out the world in which we're going to be living in. The question - the first one about ice: Do we invest in more icebreakers? You know, whether you're an oil company looking to explore, or the military looking to patrol these areas, or do we save our money and invest in other things: you know, shoring up our northern borders? Because humans have a relationship with the planet on which we live, the very study of that planet inevitably leads to improving that relationship and I think, you know, that might be a good lead-in to the video, from Bill.

Michelle: That's right, and something that we talked about today in a number of different ways is the idea of connections, about how different processes in the Earth and the atmosphere, the ocean, the land, they may be related in ways that we haven't even considered yet, that we're still learning about how connected everything is and one of the scientists here at Goddard, Dr. Bill Lau, is actually studying how weather in one part of the world can influence the entire cycle of weather for the next few months in other parts of the planet and so I believe we have a short video about Bill's work actually linking, in this case, fires in Russia to later floods in Pakistan.

Bill: What my research has been focusing is on the Russian fire and also the Pakistan flood. What we find is something really interesting is that in fact that even though these two events are separated by spatially, thousands of kilometers away, we find that they're actually connected. Actually there's a causal factor linking the two of them. We found out that they were connected by a large-scale atmospheric phenomenon, which is waves in the atmosphere, so-called Rossby waves, and so the Russian fire is initiated by an atmospheric weather pattern called blocking. What happened is that this case, the Russian fire started with actually already a dry land condition over the land area in the Russian area. So when the atmospheric blocking pattern happened, then it actually allowed this dryness to be continued and intensify: as a result, this produces what we call in atmosphere and in climate something called a feedback process, positive feedback. Something will lead to something else and it's continued to magnify on its own. It magnifies itself to the point that it has what you call in the climate community a teleconnection. Connection, tele- means long-distance, so a teleconnection from the Russian blocking situation down to the Pakistan region.

Waleed: So I think one thing that's important is that we are finding time and again what happens in one place can affect what happens elsewhere or perhaps the underlying causes may be the same even though they're far apart and I run into with this with ice all the time. I get this a lot, "It's so far away, you know? Why do I care? I'm trying to, you know, grow corn in Kansas." or " I'm trying to do something in the United States, and why do I care about that?" Well, because even in Antarctica, you know, most of the oceans' bottom water originates in Antarctica and spreads all over the globe, so even what happens in Antarctica has a direct link to what's happening here and just as Bill had shown in his video, we have fires and floods: two very extreme occurrences that have direct impacts on human life, that are closely coupled even though they're 1,000 miles away.

Michelle: There are so many of these relationships that we've just never even discovered. I mean, it was a surprise that fires in Russia could affect floods in Pakistan. How many of these other links are yet to be found?

Waleed: We'll wait and see, [laughter] you never know how many, because there will always be more.

Erin: Fantastic. Well, we have some more questions. From a 5th grade class at Cesar Chavez Elementary School: they are wondering, they really have hung up on the interconnectivity of every - of all the systems on planet Earth. They're asking, "What can we do as humans to help?"

Waleed: To help - if the question is to help make a better place, in light of these interconnections, you're focusing on something very important, and that is that things we do can actually make a difference. Now, I hear from some people, "I just don't...The Earth's a big place, you know, and I just don't see how people can have that much of an impact on it." But you know, maybe one person won't, maybe 1,000 people won't, but 8 billion people can, and it has to do with the way we live, the way the pollution that we put in the atmosphere or the emissions we put in the atmosphere will make the environment -- can make it warmer, can make it less friendly to our lungs. One discovery that was made years ago was the chemicals we're putting in aerosol cans were affecting ozone levels in Antarctica, which interestingly enough could increase cancer rates in a southern nation like New Zealand, so there are all these connections and we certainly can make a difference and my fear is there's a little too much focus on the negative difference people can make and I think people can make a positive difference and the way you do that is you start with yourself: you be aware. You learn about how these things work so that when there's discussion going on and some say, "It's this way," and others say, "No, it's that way," and "You're wrong," and "You're wrong," you have enough of a basic knowledge to hear those discussions, those arguments and come to an informed conclusion about how you feel. Once you come to a conclusion about how you feel, and you can make choices about your own personal action, you then set an example. You can put something in motion. Your friends may say, "Why are you doing that? Why are you doing it that way?” Look at all the Priuses out on the road: you know, it started with a few - a car company saying, "Hey! There's a market here." I'm sure it was a business-driven decision that had benefits for the environment. A few people bought them, said, "This is cool. I'm making a statement." And then, you know, now there are millions of these things out... well, hundreds of thousands maybe [laughter] out on the road. So you start with yourself: figure out how you feel, what you want to do as an individual. Share that. Make it important to your friends, make it important to your family, try and have them make it important to other people and what you end up getting is a ripple effect, and you can - I don't want to use the term carelessly - but you can start a movement, you know, you can do your part to elevate the national and international consciousness and when that's done in society, when that's done at a peer-to-peer level, friend-to-friend and so on, the political forces, the policy forces will respond to that sort of thing and once elected officials realize, "This is important to my constituency," whatever it is, they will figure out how to serve their constituency by addressing these issues. So, it starts with educating yourself, it's followed up by making your own choices in what you perceive to be a responsible manner. Sharing with others why you do it that way, hopefully in a way that's contagious, if it's that important to you, or infectious, so that they do the same thing and, you know, it's... What's the saying? A 1,000-mile journey begins with a single step. It's - you can be that step.

Michelle: Absolutely, that was a terrific question.

Erin: We have another one from the fifth graders at Cesar Chavez. They are wondering, "How long do we have before the ice is finished melting?” So if you could use your crystal ball and predict... [laughter]

Waleed: Well, it depends on the kind of ice. So there are three kinds of ices I'll talk about. One is the sea ice, what we showed in the animation, which I think the question is about. We don't know when that will be all melted, or even if - it could come back. But the longer it continues to shrink, the harder it is for it to come back. So every year that we get less and less, it becomes more and more likely that it will totally go. Some have estimated as little as five more years, I don't think so. I think if you sort of took an overall -- if you asked all the ice scientists in the world to bet, it'd sort of settle in on couple of decades. It could be sooner, it could be longer, and I want to stress - it could be not at all: that is not necessarily the outcome. But I think we're looking at a decade or two. And the other ice, Greenland, Antarctica: that's... I mean, that's millions, well, thousands of years to hundreds of thousands of years. But I don't worry...

Erin: This will not be happening tomorrow.

Waleed: Yeah, I don't worry about it all going away. What I pay attention to is how much is going to go away in the next 50 years or 30 years or whatever, because together they hold the equivalent of about 65 m of sea level rise, so what is that? 220 feet of sea level were it all to melt. That 's not going to happen. But if one meter's worth melts, that has huge implications for coastal regions. So we're trying to figure out what...what it's going to be, so that we can plan accordingly.

Michelle: This actually is getting down to a very fundamental issue and that is: how can we predict what's going to happen? And like you said we're not sure, how much ice will melt, how much the sea level rise will be, so one of the things at NASA that we do, is we create models. We actually don't have crystal balls, we don't know exactly what's going to happen and exactly the extent of climate change is going to be, but we have scientists that are trying to have... The best information they have right now uses supercomputers to crunch the numbers and figure out if the trends continue, what might be happening in the future and actually one of the people we have doing that is a scientist named Gavin Schmidt, who works at the Goddard Institute for Space Sciences in New York City, and we have a video where Gavin actually talks about what a model is. How is it that NASA scientists can say "We're expecting to see ocean level to rise, we don't know how much it's going to be, what are our different predictions what are the ranges...” So, if we could go to the video, actually, Gavin can tell you a little bit about some of the models that he's working with.

Gavin: NASA obviously is very focused on what we can see from space, what we can learn from space about our own planet and so we have a lot of satellites in orbit that are producing huge amounts of data that are telling us about how the clouds are changing, how the sea surface temperatures are changing, what's going on with ozone, what's going on with aerosols and all of these things are giving a unique view of the planet as it is right now. The role of models is to integrate that information, to synthesize that information with what we know about physics, what we know about sources of aerosols, what we know about atmospheric chemistry, what we know about ocean dynamics and then build a picture that allows us to go from the information that we're seeing from the satellite to infer things about what we think about the whole planet, how it's changing. Modelers don't actually have a crystal ball. There are many, many things that are going to happen in the future that we can't predict and it's going to depend on economic development, technological development, societal development: all of those things are completely outside of the ken of a climate modeler like myself. So what we can do instead, is we can do scenarios, we can ask 'what if' questions. What if we continue to increase the amount of carbon dioxide in the atmosphere? What if we continue to increase the amount of tropical deforestation? What if we continue to increase the amount of air pollution from Asia and from the rest of the world? And we can say, "Okay, well, if those things happen then these are likely to be the climatic effects, these are likely to be the changes in temperatures, the changes in statistics of heat waves, in rainfall patterns and in rainfall intensity and we try and put those together and test them with observations that we've had over the past and we've got good information from the satellite record, and you know, even going further back where we have information from proxy records that allow us to test our whole model system and that we understand what the major drivers and the effects are.

Waleed: This is a great point because the models really are what bring it all together. They're what turn our observations and our understanding of the physics into statements about what the future may hold, and modeling really, it's math and physics informed by data. And you know, you can do... The simplest version of a model I can think of is: if you throw a ball and you throw with a certain force, at a certain angle, you can try and predict where it will land. You do this intuitively in your head, you know: you're aiming for something, you throw it and if you're good, you hit it, right? If you miss it, you adjust it the next time you throw it, and so on: that's physics. We know about gravity we know about the force with which you throw it, we know about some air resistance on the ball that you're throwing, and we can turn that into a prediction. If I throw at this force, at this angle, in this direction, it will land there. Now, climate modeling is -- I just talked about three variables right there, the force and angle and the, yes, [laughter] and the gravity. Climate modeling pulls in so much more and it's so much complex, but the basic idea is the same. There are physics at work and we can describe the physics with mathematical equations. We build these equations and we put in what we know. How much carbon dioxide's in the atmosphere? What the reflectance... How much ice there is? How much energy ice reflects? How much forests there are? How much energy the forests reflect... these are just a few variables and we build them and build them and build them and when we get a description of how the world is working today or perhaps how it worked in the past, we can run them backwards effectively, we start to believe the models, or at least know how, where their weaknesses are, where their strengths are. We run them forward for scenarios as Gavin had pointed out and we introduce or we make our best estimate of a range of futures, much like figuring out where that ball might land and so it comes down to physics and information, described with math, run through computers, to tell us what tomorrow has a good chance of looking like, not exactly, but sort of, the best we can come with.

Michelle: It's a wonderful point that there's so much we don't understand, that, you know, all of the students that are writing in to us today from their classrooms: there's so much work for you to do in the future and try to find out exactly what's going to happen to the Earth's climate. What will be changing in your lifetime and hundreds of years from now and these are things we're really just starting to get a handle on. Huge amount of work to be done.

Waleed: We'll not solve it before you're ready to enter the workforce.

Michelle: We need you. [laughter]

Waleed: Charge ahead!

Michelle: That's right. [laughter]

Waleed: You may solve it, we won't.

Erin: Terrific! Well, we have one final group of questions from our webcast viewers. This is from Mrs. Weaver's fifth graders at Cecil County Public School. They first ask, "How are the levels of carbon dioxide's measured in the atmosphere?

Waleed: Oh, wow! Carbon dioxide is measured... we have instruments: we launch balloons; they carry instruments that can measure the carbon dioxide, the vertical structure of the carbon dioxide. We also measure them on the surface at different locations and we use models to figure out -- to take that surface measurement at that location to figure out what it must look like higher up and in the vicinity and if you take carbon dioxide measurements at places, a dozen places in hundred mile radius, you can create sort of a picture or image of that distribution of energy. On the animation you're seeing here: that graph came from on location in Hawai'i, Mauna Loa. We have a -- which we couple with other locations, try and figure out what it's doing worldwide. We have a satellite mission in development, Orbiting Carbon Observatory 2, that is intended for this very purpose: to do a global map from space of carbon dioxide and other carbon in the atmosphere and without getting too much into details: if we sent energy at a certain wavelength -- well, energy travels in waves, in short wavelength the waves are small; long wavelengths the waves are long, and there are certain wavelengths, certain lengths of that wave where carbon dioxide actually is very absorbent: it resonates with that wave, it absorbs energy at that wavelength. So by measuring the absorption of energy from space, or you can do this from the ground, at a certain wavelength, the more of that energy that's absorbed, the more carbon dioxide must be there, so you put that together, and you've heard me say "story" a lot but really, to tell us the story of the carbon dioxide and where it is and how much there is.

Erin: Excellent.

Michelle: And once again, we have an example of NASA doing things from space, but also the extensive ground-based observations that we do, as well.

Waleed: Yeah, absolutely.

Michelle: So there's...being a NASA scientist could mean traveling the Earth and setting up these different detectors and studying the carbon dioxide content, or you mentioned that you had been in Greenland, actually. What were you studying when you were in Greenland?

Waleed: Oh, I was... I was trying to figure our how we can watch ice melt from space, that's what I tell my kids. Because when ice melts, it looks different to a satellite than when it's frozen. It looks different to your eye. Melting ice is darker: it just looks wet. Well, at certain wavelengths, again, melting ice has a very strong signal. So I went to Greenland to measure melt as the satellites flew overhead I was carefully keeping track of the ice melt. For a couple of months I lived in a tent, waited for melt to come and when it did, I measured how much it was and then went back home and compared it to the satellite data. So we do what's called ground truthing: where we go somewhere, make a measurement up-close in more detail than we can from space, compare it to the space-based observation: when we're confident that we are doing it right from space, we can then apply it elsewhere so we don't have to go to every point on the globe. The satellites can do it, but a critical step is making sure we understand what the satellites are seeing.

Erin: I'm glad you brought up the word satellite because we actually have a question from Mrs. Weaver's fifth graders on satellites, getting to do the technology portion of this.

Waleed: Sure, sure.

Erin: "How are images transmitted via satellite?"

Waleed: Oh, they're transmitted in much the same way as your wireless telephone works. We have a -- it's using microwaves, or electromagnetic radiation. So the satellite makes a measurement and stores it on devices in the satellite and then as it passes over certain parts of the Earth, the Polar Regions are good because satellite orbits sort of converge at the poles. There are more...You can imagine a satellite going around my hand like this as the Earth spins under it. I'm always going over the top and bottom of the Earth, right? So we have more concentrated observations at the poles. So we put ground stations in -- Svalbard, which is way north and McMurdo Station in Antarctica, in Sweden, in Alaska and elsewhere, so that when a satellite passes over it, it basically makes a quick phone call and it just sends the information down in the couple of minutes that it's within sight of the station and says, "Here's everything I collected since we last talked or since I last dumped data at another station elsewhere" and then they all flow into some central, sort of, collection facility and it's turned into, you know, it's processed, it's examined and turned into information that is then made available to the public.

Erin: Excellent, we've had some fantastic questions from our webcast viewers.

Waleed: Yes we have, they're great.

Erin: Thank you so much for sending in these terrific questions. We only have a few minutes left, so Waleed, do you have any final thoughts for our students today?

Waleed: Boy...I have a couple. One is: I talked about elements of the Earth and it being a system and the way I look at it is that it's kind of like a mosaic. The Earth is a mosaic of stories: it's the story of the ice, it's the story of the rain, it's the story of the plants, it's the story of the land, and when you put the tiles of that mosaic together as we're trying to do, you get the story of the Earth and doing it from space coupled with ground observations is really a powerful way of getting the perspective and context to really tell and understand that story. The second thing I would say is that we need smart people working at this and trying to figure it out. This is important for our lives, it's important for society, it's important for humanity, and it's just plain interesting. It's discovery but it's also a service to society and the question about making a difference, well, the biggest step we can take in making a difference is educating, not just ourselves but those around us. So I and my colleagues work to understand, but also work to tell that story and I would encourage all of you wherever your careers, or your college or your ambitions take you, to think about this story and think about how important it is and just be thoughtful in your actions and considerations and your assessment of the information you hear and what you choose to do with it.

Erin: Thank you so much, Waleed, for joining us today, I know I certainly learned something about how Earth Science is all around us. How about you Michelle?

Michelle: I think that one of the things I just loved about the discussion today, is I think it gives all the students in the audience a chance to see the different things you can do that involve a career at NASA. I mean, not only do we have scientists in Greenland or in Antarctica; we have people that are designing the satellites, building the satellites. A lot of the animations you've seen today, those beautiful pictures of different data sets of ice or the ocean, those are from our Scientific Visualization Studio. We need computer people, we need artists: there so many different ways to work for NASA and for something as complex as Earth Science: where we're trying to study basic questions about: How’s precipitation work? How much will the ice melt? How's our climate changing? What's going to be going on with hurricanes? There are so many different possible ways to study the planet and so I always end up being inspired by just the sheer amount of work that we have that we need good people to come and help us with.

Erin: Absolutely. Michelle, thank you for joining me today, it was so much fun sharing the cohosting duties. [laughter]

Michelle: A lot of fun. Thank you very much.

Erin: Absolutely. On behalf of everyone here, thank you so much for joining us today. I hope you learned something about how Earth Science is all around you and I hope we inspired you to pursue the Sciences, Technology, Engineering and Mathematics. Until next time, goodbye from NASA everyone. Take care.

Waleed: Bye-bye.