1 00:00:00,000 --> 00:00:04,010 Interviewer: Earth's rising seas are some of the most visible signs of our warming planet 2 00:00:04,010 --> 00:00:08,120 over the last 20 years NASA satellites, air borne missions, and field campaigns have shown 3 00:00:08,120 --> 00:00:12,290 a steady rise in global sea levels as the world's polar ice sheets melt. 4 00:00:12,290 --> 00:00:16,480 Here to tell us more about this is Dr. Tom Wagner from NASAs Goddard's Space Flight 5 00:00:16,480 --> 00:00:20,650 Center. Start by telling us you know you have some new images. What are these new 6 00:00:20,650 --> 00:00:24,820 images show us about sea level rise? Dr. Wagner: You know they show us two really 7 00:00:24,820 --> 00:00:28,980 important things; you know and first thing is this, sea levels are rising around 8 00:00:28,980 --> 00:00:33,160 the world and in the last 20 years they've risen by over 3 inches 9 00:00:33,160 --> 00:00:37,330 on average. And we know this number really well, it's actually recorded by a number of 10 00:00:37,330 --> 00:00:41,500 different satellites that go over the Earth and bounce radar signals off the ocean 11 00:00:41,500 --> 00:00:45,670 to determine its height. The other amazing thing though is that the ocean has 12 00:00:45,670 --> 00:00:49,840 topography. You know you can almost think of it like a mountain range with peaks and valleys. 13 00:00:49,840 --> 00:00:54,010 And the coast of California in this case actually is a little bit of a valley right now 14 00:00:54,010 --> 00:00:58,190 and this is caused by a combination of wind and ocean currents. But what people really 15 00:00:58,190 --> 00:01:02,370 need to take away is that sea level is rising and it's going to continue to rise and it's rising enough 16 00:01:02,370 --> 00:01:06,550 that it's already impacting us. 17 00:01:06,550 --> 00:01:10,730 Interviewer: What's causing 18 00:01:10,730 --> 00:01:14,920 sea levels to rise? Dr. Wagner: What's causing sea level to rise are two basic things. One is that 19 00:01:14,920 --> 00:01:19,090 as the planet warms up the volume of the ocean expands 20 00:01:19,090 --> 00:01:23,260 and that's about half of the sea level rise. The other half comes from 21 00:01:23,260 --> 00:01:27,440 melting of ice that's on land. In particular the glaciers and ice caps of Alaska and 22 00:01:27,440 --> 00:01:31,620 Canada and also the major ice sheets of Greenland and Antarctica. 23 00:01:31,620 --> 00:01:35,800 And we have this other amazing satellite called GRACE which actually allows us to 24 00:01:35,800 --> 00:01:39,980 map changes in the weight of the ice sheets. And what we found is that in the Greenland 25 00:01:39,980 --> 00:01:44,160 case, we're not only losing ice but the ice loss seems to be accelerating 26 00:01:44,160 --> 00:01:48,330 and that's something that we're trying to account for in our models as we move forward. 27 00:01:48,330 --> 00:01:52,520 Interviewer: What is NASA doing to understand how much sea level could rise in the future? 28 00:01:52,520 --> 00:01:56,700 Dr. Wagner: NASAs doing three basic things you know one is we're developing the technologies 29 00:01:56,700 --> 00:02:00,880 to study sea level rise and then we're deploying them on 30 00:02:00,880 --> 00:02:05,060 satellites and also on aircraft to measure how fast the oceans going up. 31 00:02:05,060 --> 00:02:09,230 But we're also trying to understand the processes that are driving the ice loss and that's why 32 00:02:09,230 --> 00:02:13,400 we put scientist out in the field to study what's going on with the ice itself. Both 33 00:02:13,400 --> 00:02:17,590 on the ice and in the oceans around the ice cause that's an important factor. And then 34 00:02:17,590 --> 00:02:21,770 finally we pull all that data together into models and those models are 35 00:02:21,770 --> 00:02:25,950 important for us to understand the processes of ice loss and also to do the forecast 36 00:02:25,950 --> 00:02:30,120 into the future to kind of produce those numbers that society needs to 37 00:02:30,120 --> 00:02:34,300 plan for 10, 50, 100 years after. Interviewer: So where can we learn 38 00:02:34,300 --> 00:02:38,480 more and see some of these images. Dr. Wagner: One of the best place to go is 39 00:02:38,480 --> 00:02:42,660 nasa.gov/earth where you can learn all about the work that we're doing right 40 00:02:42,660 --> 00:02:46,660 now, the data sets, that are available to see, and also learn about other NASA programs 41 00:02:46,660 --> 00:02:49,469 studying the Earth.