Transcripts of NASM-Dr

[Applause] Good evening, thank you Lola and before I start I just wanted to say that Lola couple of years ago won the Presidential Early Career Award in Science and Engineering, super honor, congratulations. I think it's really cool [Applause] So anyhow yeah we so anyhow we have good people Goddard, incase you haven’t noticed. So now, let's get to the cool part of this evening. The ice or we scientists call it lovingly the cryosphere or we use fancy words to make it sound better. Now the bad news for the ice, the earth is getting warmer and that's just a fact and no matter what you think about, global change, global warming etcetera, it is getting warmer and it's most pronounced at polar latitudes. It's especially true for the Arctic. We at Goddard, we have NASA I should say, we like to include JPL sometimes, we at Goddard and PL a study of the Arctic from the satellite. It's a very hostile environment; it's only with satellites that we have. Now a data record of what's going on in the Arctic and the graph behind me, you see the temp of evolution of Arctic sea ice during the summer. In the early years of microsatellite imagery it was relatively stable and scientist detected a slight decrease and sea ice extent. But over the last year this trend has increased, the negative trend has increased tremendously and there is absolutely no doubt anymore from many scientist that the Arctic sea ice is shrinking tremendously. These trends are statistically significant. To understand better what's going on we need to understand that the ice, the Arctic sea ice, it's completely different from the frozen lake in your neighborhood. It's a highly, very highly dynamic system. It moves around like a pulsating living being and you can see for example west of Greenland and especially east of Greenland, these big streams, current of thick ice, it is leaving the Arctic system and it's way more than as I said a frozen lake. There are constant openings and closing and these openings where the heat from the ocean is getting into the atmosphere. It's a very complex system, it's very beautiful too I have to say and this is why it is so completed to predictions and if actually I could do prediction I would become a stock broker. So if the ice is shrinking and thinning, it's more subjective to changes in the atmosphere and oceanic conditions. he record minimum we observed in 2012 is largely driven by the storm that developed over the arctic that moved a lot of ice out of the Arctic ocean and so we are seeing these interactions between ocean atmosphere and ice more dramatically than we have seen in the past when we had a more consolidated pack of ice pack. So we see these drastic changes in the Arctic, on the other side you see the Antarctic and people notice hey, what's going on, the Arctic is changing, the Antarctic is not changing as much. As a matter of fact we see a slight increase in the Antarctic. The reason is these are completely different... completely different climate systems. For example, just to say one example, in the Arctic, at the North Pole we have ocean which is surrounded by land. So the opposite is true, in the southern hemisphere we have land mass which is surrounded by ocean and talking about land masses similar to the sea ice, the ice sheets are dynamic as well. Again it's not just a stable ice sheet. The way ice sheets work is it's snows, it's a center of the Arctic of the ice sheet Antarctica or Greenland and this ice is slowly moving towards the edges of the continent and breaks off as icebergs and if the system is imbalanced, the mass of snow equals the mass of the ice bergs that are breaking off. In addition to this though, we have seen increased melt, we had a record melt in Greenland a year or two ago, and in addition to melt itself we know that some of the melt waters accumulate as ponds on top of the ice, can drain to the bottom of the ocean... to the bottom of the ice sheet and lubricate the interface between the ice sheet and the bedrock, causing an extreme acceleration of glacier flow. Some of the glaciers especially around Greenland accelerated for more than 100%. We have satellites that can actually directly measure the mass of the ice sheets. One of the coolest concept, I mean as a physicist I think it's a really cool concept, it's Grace, and GRACE does not look upwards or downwards, it actually just measures the distance between itself, between the two satellites and that with a precision with less of the width of a hair. The first satellite goes over a field of high gravity its accelerated ever so slightly and the distance between the satellites increases until the second satellite is over the same gravity hill and the distance becomes equal again. So using results from Grace, we can actually determine directly the mass of the ice sheets and if you look at the time series derived from Grace over Greenland, we can see we have tremendous, tremendous losses. We are losing right now about 200 gigatonnes of ice every year, every year, so I can, to provide an analogy, it is a kilometer, by kilometer, by a kilometer of ice is one gigatonne, or 200 gigatonnes, I did some math on my way out here, 200 gigatonnes of ice would cover the State of California roughly, with half a meter. So, we can add, half a meter every year for California. If Senator Nelson would still be hereit is almost equal equal to area in, I think its equal close to the area of Florida. So and then we launched ICESat-1 in 2003, this was a first laser alternator that surrounded earth and we got a much better view in terms of how is elevation changing around Greenland, around Antarctica and it provided the first measurement of Antarctica as well as the Arctic sea ice. Before then, we were very pretty much blind of the third dimension of the ice sheets and the sea ice. So it was a real cool mission and very NASA, I think. ICESat-1 ended in 2009 and after that we started a campaign called operation IceBridge. The scientist, and fortunately, headquarters as well, realized we cannot afford to be completely blind to the fast changing conditions in the climate regions. So we are flying twice a year, over the key regions in the Arctic as well in the Antarctic, and instead of showing more data, I thought let's look just at some of the pictures because I had the honor and the privilege of flying on some of these missions. It is just phenomenal flying over, it's 1500 feet, 500 meters, it is really close flying over the ice sheets and sea ice. You fly over glacier and you have mountains left and right. In addition to lasers, we have radars that penetrate the ice, so we can actually measure the ice thickness as well, and then of course, with all the objectivity of a project scientist, in 2017, we launched ICESat-2, which is so cool and so phenomenal, and this is NASA at its best in my opinion, because it is ground breaking technology and ground breaking science. With ICESat-1, we measured the earth every 150 meter, roughly, if you think about football, football seasons are started, basically in the end zones. With ICESat-2, we measure with centimeter precision, every yard line, which is really cool. And it will be a really discovery mission, and in addition to monitoring the ice sheets, we will monitor the height of trees, changes in the land, maybe tectonics, height of the oceans etcetera. It will be a real discovery mission, I am very, very excited about it, and worked very hard. When I was a young scientist, this is my last slide, just ten years ago, I went to Antarctica to measure sea ice thickness. This was then ten years ago, before ICESat-1 launched, the only way we could measure sea ice thickness, it was no other means. We went there and drilled lots and lots and lots of holes. It was great fun of course and we do had some visitors as well, as you could see at the top, what is it from your side, top left, isn't it amazing to just come out and look what we are doing? So, I think NASA does really cool stuff for cryosphere scientists and we have come a long way since ten years ago, when I went down there to take measurements of the ice and with this, I want to give the microphone Piers Sellers former astronaut and my boss. [Applause]