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[Applause]

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Good evening, thank you Lola and before I start I just wanted to say that

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Lola couple of years ago won the Presidential Early Career

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Award in Science and Engineering, super honor, congratulations.

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I think it's really cool [Applause]

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So anyhow yeah we so anyhow we have good people Goddard, incase you haven’t noticed.

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So now, let's get to the cool part of this evening.

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The ice or we scientists call it lovingly

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the cryosphere or we use fancy

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words to make it sound better. Now the bad news for the ice,

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the earth is getting warmer and that's just a fact and no matter what you think about,

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global change, global warming etcetera, it is getting

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warmer and it's most pronounced at polar latitudes.

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It's especially true for the Arctic. We at

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Goddard, we have NASA I should say, we like to include JPL

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sometimes, we at Goddard and

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PL a study of the Arctic from the satellite. It's a very hostile

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environment; it's only with satellites that we have. Now

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a data record of what's going on in the Arctic

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and the graph behind me, you see

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the temp of evolution of Arctic sea ice

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during the summer. In the early years

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of microsatellite imagery it was relatively stable and scientist

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detected a slight decrease and sea ice extent.

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But over the last year this trend has increased, the negative trend

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has increased tremendously and there is absolutely no doubt anymore

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from many scientist that the Arctic sea ice is shrinking

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tremendously. These trends are

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statistically significant. To understand better what's going on

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we need to understand that the ice, the Arctic sea ice, it's completely

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different from the frozen lake in your neighborhood.

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It's a highly, very highly dynamic system. It moves around

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like a pulsating living being and you can see for example

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west of Greenland and especially east of Greenland, these big

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streams, current of thick ice, it is leaving the Arctic system

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and it's way more than as I said a frozen lake. There are

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constant openings and closing and these openings

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where the heat from the ocean is getting into the atmosphere. It's a very

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complex system, it's very beautiful too I have to say and

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this is why it is so completed to predictions and if actually I could

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do prediction I would become a stock broker.

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So if the ice is shrinking and thinning,

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it's more subjective to changes

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in the atmosphere and oceanic conditions.

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he record minimum we observed in 2012 is largely driven

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by the storm that developed over the arctic that moved a lot of ice

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out of the Arctic ocean and so we are seeing

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these interactions between ocean atmosphere and ice

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more dramatically than we have seen in the past when we had a more consolidated

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pack of ice pack.

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So we see these drastic changes in the Arctic,  on the other side you see the Antarctic

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and people notice hey, what's going on, the Arctic is

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changing, the Antarctic is not changing as much. As a matter of fact we see a

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slight increase in the Antarctic. The reason is these are completely

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different... completely different climate systems. For example,

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just to say one example, in the Arctic, at the North Pole we

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have ocean which is surrounded by land.

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So the opposite is true, in the southern hemisphere we have land mass

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which is surrounded by ocean and talking about land masses

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similar to the sea ice, the ice sheets are dynamic

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as well. Again it's not just a stable ice sheet.

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The way ice sheets work is it's snows, it's a center of the Arctic

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of the ice sheet Antarctica or Greenland and

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this ice is slowly moving towards the edges of the continent

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and breaks off as icebergs and if the system is imbalanced,

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the mass of snow equals the mass of

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the ice bergs that are breaking off. In addition

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to this though, we have seen increased melt, we had

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a record melt in Greenland a year or two ago, and in

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addition to melt itself we know that some of the melt waters

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accumulate as ponds on top of the ice, can drain to the bottom

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of the ocean... to the bottom of the ice sheet and lubricate the interface

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between the ice sheet and the bedrock, causing

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an extreme acceleration of glacier flow. Some of the glaciers

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especially around Greenland accelerated for more than 100%.

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We have satellites that can actually directly measure

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the mass of the ice sheets. One of the coolest concept, I mean as

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a physicist I think it's a really cool concept, it's Grace,

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and GRACE does not look upwards or downwards, it actually just measures the distance

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between itself, between the two satellites and that with a precision

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with less of the width of a hair.

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The first satellite goes over a field of high gravity

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its accelerated ever so slightly and the distance between the satellites increases

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until the second satellite is over the same

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gravity hill and the distance becomes equal again.

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So using results from Grace, we can actually

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determine directly the mass of the ice sheets

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and if you look at the time series derived from Grace

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over Greenland, we can see we have tremendous, tremendous losses.

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We are losing right now

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about 200 gigatonnes of

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ice every year, every year,  so I can, to provide

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an analogy, it is a kilometer, by kilometer, by a kilometer

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of ice is one gigatonne, or 200 gigatonnes, I did some math

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on my way out here, 200 gigatonnes of ice would

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cover the State of California roughly, with half a meter.

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So, we can add, half a meter every year for California.

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If Senator Nelson would still be hereit is almost equal

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equal to area in, I think its equal close to the area

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of Florida. So and then we launched

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ICESat-1 in 2003, this was a first laser

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alternator that surrounded earth and we got a much better view in terms

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of how is elevation changing around Greenland, around Antarctica

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and it provided the first measurement of Antarctica as well as

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the Arctic sea ice. Before then, we were very pretty much blind

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of the third dimension of the ice sheets and the sea ice. So it was a

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real cool mission and very NASA, I think.

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ICESat-1 ended in 2009 and after that

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we started a campaign called operation IceBridge.

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The scientist, and fortunately, headquarters

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as well, realized we cannot afford to be

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completely blind to the fast changing conditions in

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the climate regions. So we are flying twice a year,

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over the key regions in the Arctic as well in

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the Antarctic, and instead of showing more data, I thought

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let's look just at some of the pictures because I had the honor

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and the privilege of flying on some of these missions. It is just phenomenal flying over,

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it's 1500 feet, 500 meters, it is really close flying over

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the ice sheets and sea ice. You fly over glacier and you have

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mountains left and right. In addition to lasers, we have radars that

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penetrate the ice, so we can actually measure the ice thickness as well,

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and then of course,

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with all the objectivity of a project scientist, in

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2017. we launched ICESat-2. which is so cool and so

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phenomenal, and this is NASA at its best in my opinion,

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because it is ground breaking technology

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and ground breaking science. With ICESat-1, we measured

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the earth every 150 meter, roughly, if you think

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about football, football seasons are started, basically in the end zones.

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With ICESat-2, we measure with centimeter precision,

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every yard line, which is really cool.

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And it will be a really discovery mission,

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and in addition to monitoring the ice sheets, we will monitor the height

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of trees, changes in the land, maybe tectonics, height

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of the oceans etcetera. It will be a real discovery mission,

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I am very, very excited about it, and worked very hard. When I was a young

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scientist, this is my last slide, just ten years ago,

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I went to Antarctica to measure sea ice thickness. This was then

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ten years ago, before ICESat-1 launched, the only way we could

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measure sea ice thickness, it was no other means. We went there

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and drilled lots and lots and lots of holes.

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It was great fun of course and we do had some

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visitors as well, as you could see at the top, what is it from your side, top left,

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isn't it amazing to just come out and look what we are doing?

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So, I think NASA does

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really cool stuff  for cryosphere scientists and we have come a long way

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since ten years ago, when I went down there to take

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measurements of the ice and with this, I want to give the microphone

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Piers Sellers former astronaut and my boss.

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[Applause]