[Interviewer] “Joining us now from NASA’s Goddard Space Flight Center is Dr. Tom Wagner
who is going to tell us a little bit more about Arctic sea ice. Thanks for joining us.”
[Wagner] “Thanks for having me.”[Interviewer] “So last year was a record-breaking year for sea ice loss
in the Arctic. What are we seeing this year?”[Wagner] “Well the good news is we’re not on
track for another record. But the bad news is the ice didn’t really heal up anyway
and it’s still shrinking into one of the lowest years on record and about the thinnest ice we’ve ever had as well.”
[Interviewer] “So what does the long term trend look like?”
[Wagner] “The long term trend is this. If you go back to like the 80s, we’ve lost more than half the sea ice that used
to be around in the 80s. And we’re continuing over this last decade
this ever-increasing loss of ice during the summer, but also this
startling thinning that’s been going on as well. And so there’s people who talk
“hey are we going to be reaching ice-free summers in the next few years”
probably not. We’ll probably always form some ice over the North Pole where it’s cold, but the point is
there’s so much ice lost that the Arctic is in a new state.”
[Interviewer] “But the Arctic is far away. How does sea ice melting
impact us in the United States or globally?”
[Wagner] “Loss of Arctic sea ice is profoundly important for the globe for a number of reasons.
First of all it’s one of the biggest knobs on global weather. This is one of the biggest
physical changes on Earth. We have an ocean that used to be covered with a solid surface that’s going away.
It affects the position of the jet stream which will now extend further north
and further south and cause blocking patterns that could increase those periods of
extreme heat and extreme cold in the U.S. But that’s just kind of the
simplest thing. It could also affect storm tracks like Superstorm Sandy.
It could also affect globally those weather patterns and those are the kind of cutting edge research questions
that we’re working on right now. But also too
the Arctic has massive stores of methane in the permafrost and also
on the seabed. As we lose the sea ice we have more heat
going into the ocean and we can also transport that heat, cause more permafrost thawing,
destabilize the seabed, potentially trip the release
of all this methane which could cause big spikes in global temperature.
Also too the Arctic is overall the canary in the coalmine.
The polar regions heat up faster than the rest of the planet.
Basically in the tropics they’re getting warmer too, but that heat gets invected up into the atmosphere
and gets pushed north and south. So the polar regions are kind of where
the place where you would expect to see right away the warming effects really take place
and that’s exactly what we’re seeing in the Arctic. And finally the Arctic is just one of the
most fascinating, least explored places on Earth. You know the amazing
animals like polar bears. You have these unique whales like the Narwhals
and you have this really interesting ecosystem involving things like algae
forming near the surface and sinking to the bed and creating this rich benthic environment that
walruses then come in and exploit. And all of that is changing
right now in real time.”
[Interviewer] “So tell us what is NASA doing to better understand what’s going on in the Arctic?”
[Wagner] “NASA does a couple of different things. First and foremost are the satellite studies.
We use a range of satellites that document the sea ice and understand its connection to the global drivers of change.
We also have some of the most sophisticated research aircraft in the world
and we fly over the ice and shoot at it with lasers and radars
and we have other devices to measure the variations of the Earth’s gravitational field
and magnetic field. All to understand what’s going on with the ice.
We don’t just work on the sea ice, we also study the glaciers of Alaska,
the Canadian ice caps and the Greenland ice sheet where there’s been a lot of changes in recent years.”
[Interviewer] “Can you tell us a little bit about some of the changes in Greenland?”
[Wagner] “So last year for the first time in the record we had extensive
melting across the entire surface of Greenland. Even the really high
high cold parts. Also too are satellite data shows us that Greenland is
not just losing more ice, it’s accelerating in its ice loss.
And it’s losing ice not just from the warm south but also from the cold northern regions.
And what people need to understand is that this isn’t just one
study or one type of data, we shoot bounce lasers off the ice
to measure the height. We use radar to study how fast the ice is flowing.
And we actually use a satellite called GRACE, which is a pair of satellites orbiting the Earth,
, that directly measure the mass change itself. And we have people out on
the ground walking around and looking at this and banging GPS devices and looking at how
fast sea ice is flowing into the ocean. And the simple fact is we’re losing
a lot of ice out of Greenland.”[Interviewer] “What can you tell us about Antarctica?”
[Wagner] “Antarctica is also a fascinating place and we’re losing
a lot of ice from Antarctica particularly west Antarctica. With east Antarctica
it’s a little bit more ambiguous. The problem is again we’re characterizing
continental scale areas and we’re looking at subtle changes in ice.
In some areas along the coast from satellites we can see that we’re losing
30 feet of ice a year. Some of this is balanced by the amount of snowfall
that falls in the interior of Antarctica and we’re working out that balance now.
But overall Antarctica looks like it’s losing a lot of ice. Also too there’s sea ice
that surrounds Antarctica that’s kind of analogous to the sea ice at the North Pole.
The thing is though every year the Antarctic sea ice grows and then almost all of it retreats,
but in recent years there’s been a little more growth of sea ice in some areas.
So overall the Antarctic sea ice has been increasing a bit. But it’s a very
different thing than what’s going on in the Arctic.”
[Interviewer] “Where can we learn more about all of this?”
[Wagner] “One of the best places to go is NASA.gov/earth and you can also go to ice.nasa.gov.
[chimes]