[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]