Transcripts of Interview with Dr. Tom Wagner

Interviewer:Dr. Wagner, can you tell us exactly what sea ice is and what's new about it this year?
Wagner:Sea ice forms on the ocean in the winter months, and the image you're looking at right here is a picture of the top of the planet -- not a model, not a simulation, not an artist's impression but this is actual data from a satellite showing us the sea ice cover on the Arctic Ocean. And what's really important to us is we're trying to understand how that sea ice changes over the course of the year and how much it melts back and what we're looking at is just changes over the last six months here.

Interviewer:Well, can you tell us why sea ice is important?
Wagner:The reason that sea ice is important is that it's kind of one of the main controls on weather over the whole planet. The Arctic Ocean actually functions as kind of like a mirror or hat up on the surface of the Earth, and as that ice begins to decrease and melt away, that sunlight encounters dark ocean where it gets absorbed and begins to heat the ocean up. And what happens is that normally Pacific and Atlantic water goes into the Arctic, gets cooled off, and becomes denser and sinks and flows out as ocean circulation. And ocean circulation is what sets the weather and the climate for the entire planet. So as we change the Arctic Ocean we change that. But we also change the Arctic itself quite a bit. You've probably heard about some of the polar bears that as the ice decreases, they're getting taken further away from their food. But also too as that ice changes we do things like open up the Northwest Passage shown here in red. And what we're really concerned about is that over the last 30 years which is this yellow line here, that's what the average ice extent has been at this kind of minimum period after the summer melt in September. And as you can see there's a lot more blue in there -- that's a lot more open water. And what we're trying to understand is how those changes are correlated with warming of the planet overall.

Interviewer:Have you identified what's causing more sea ice to melt?
Wagner:We think that it's likely associated with warming of the planet. And the reason for that is if you look at how the planet warms, what's happened is that even just over the last couple of decades, you can see that the temperate zones warm up but the poles warm up faster than the whole rest of the planet. And it looks like the Arctic just in the last decade has probably warmed by about one to four degrees.

Interviewer:What is NASA doing in particular to better understand the polar changes and their impacts?
Wagner:NASA does three things to really understand the polar regions. The first one is we send people out. They go out there and they stand on the ice and make measurements and they try to understand how it's changing. We also use a whole range of aircraft to understand the ice. We've got everything from old spy planes to even things like a DC-8, which you may have flown on, which have all these special holes cut in them and this unbelievable array of instruments, instruments that can measure the surface of the ice. We also have things like radars that can penetrate the ice and map the bed underneath it. But probably the most important and unique thing we do is study the ice with satellites. And we need to use satellites because these polar icesheets are so vast, you need a satellite to get the coverage. And next month, we're going to launch the next polar-orbiting weather satellite, NPP.

Interviewer:What is causing our other recent dramatic events, hurricanes, tornadoes, earthquakes, floods -- is that related?
Wagner:It seems like there's been a lot of changes happening on the planet with all these natural disasters and things. In terms of like earthquakes and volcanoes, there's no evidence that there's any more of those now then there have ever been, but there's more people now. We live in more hazardous areas along coasts and fertile valleys around volcanoes and things. But the changes that are happening with weather, we're still trying to work those out. In general though the changes we're seeing are probably consistent with a warming planet, but that's kind of the edge of the research that we're working on.

Interviewer:Where can viewers go to find more information?
Wagner:The best place to go is You can also go to