00:01Hi, I'm Josh Willis, the project scientist for the Jason-3 missions to measure sea level rise from space.
00:07In some ways, sea level rise is really simple.
00:10As water heats up, it takes up more room. This drives sea level rise.
00:15And in addition, as glaciers and ice sheets are melted, extra water is added to the ocean,
00:21just like when you turn on your faucet in the bathtub.
00:23Over 90% of the heat trapped by greenhouse gases is being absorbed by the oceans.
00:28When that happens, sea water expands, and this helps drive sea level rise.
00:34Hundreds of millions of people around the world live on coastlines that can be threatened by rising seas.
00:40This animation shows how sea levels have changed over the last 23 years.
00:45Globally, sea levels have gone up by about 6 centimeters during that time.
00:50But it doesn't happen all at the same speed everywhere.
00:53Some places are rising faster than others, and some places are even falling.
00:59Orange and red colors mean that sea levels have gone up in these locations,
01:03and blue and white means sea levels stayed the same or actually fallen.
01:07We can see that most places in the ocean are orange, meaning sea levels risen over the last 23 years.
01:13In a few places, you can see blue, where sea level has actually dropped.
01:17Here we see the Gulf Stream. The red and blue indicate that this massive current has shifted slightly in the
01:23last 23 years.
01:24Off the west coast of the United States, we've seen sea levels actually drop.
01:30This is because waters there have been cooling because of something called the Pacific Decadal Oscillation.
01:35In the western Pacific, sea levels have been rising very rapidly.
01:39This is because of heat being pushed from east to west across the Pacific.
01:44Sea level rise is going to be a major impact of human-caused climate change,
01:48and here at NASA, we're doing everything we can to try and better understand it.
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