Curious Universe: Earth’s Expanding Oceans

01You know, NASA really was set up to look outwards, but also to look inwards from the outside.

02The original speech that John Henry gave where he set that target to get to the moon in a decade.

03We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard.

04Because that goal...

05The next bit of that speech was, we're going to start having weather-observing satellites to keep track of what's going on.

06Transit satellites are helping our ships at sea to steer a safer course.

07Tireth satellites have given us unprecedented warnings of hurricanes and storms, and will do the same for forest fires and icebergs.

08It's really part and parcel of the same spirit of exploration, of understanding, of data gathering.

09Our role as scientists is to help society see what those problems are likely to be, how they're going to manifest, and how maybe we should solve them.

10When you have that view from space, you see things differently.

11This is NASA's Curious Universe.

12Our universe is a wild and wonderful place.

13I'm Patti Boyd, and in this podcast, NASA is your tour guide.

14NASA might be best known for the work we do in space, but there's a lot here on our home planet we study every day.

15From increased hurricane intensities and longer fire seasons, to changes in migration patterns and growing season.

16Climate change is impacting the way our Earth functions as an interconnected system.

17Today, we're going to explore how NASA scientists are tracking and predicting the changes in our oceans.

18Hi, my name is Gavin Schmidt.

19I'm the director of Goddard's Institute for Space Studies in New York City.

20And since February, I am the senior advisor on climate to the NASA administrator.

21Scientists know that our home planet is changing due to climate change.

22Gavin's job is to keep an eye on all of it and identify how each piece of our changing Earth can impact the others.

23One of those pieces is sea level rise, or the expansion of our oceans along coastlines.

24We understand why sea level is rising at the rate it's rising, and it's rising at about three millimeters, a little bit more per year, and accelerating.

25Because we're increasing the amount of greenhouse gases in the atmosphere, there's more heat coming into the system than is leaving, and that heat has got to go somewhere, and that heat is going into the ocean.

26That three millimeters a year rising rate might not sound like a lot.

27But on average, ocean levels have risen about a foot in the past 100 years.

28And that change in ocean height is coming from a couple of different sources.

29Heat that goes into the ocean makes it warmer, and warmer water expands.

30Half of what we're seeing in terms of sea level rise is just the fact that the water, as it warms, is just expanding.

31On a molecular level, warmer water takes up more space than colder water.

32As all of those tiny molecular differences add up, the whole ocean expands.

33We can see that expansion as the now warmer and larger oceans creep up the coastline.

34But those heated molecules are only one part of our rising oceans.

35Scientists are also focused on how quickly we are extracting Earth's groundwater.

36We're taking out groundwater at unsustainable rates in many places around the world.

37And when you take groundwater out and you don't replace it, then that water ends up in the ocean as well.

38We're building lots of dams and reservoirs, and so that's keeping some of the water back.

39Groundwater is what you might find in a well.

40It provides a lot of our drinking water.

41When we pull that water out of the ground, use it, and then return it to the oceans instead of back into the ground, it adds to our rising sea levels.

42But then you've got to think about all of the mass of water that goes into the ocean.

43Because we're melting Greenland, because we're melting West Antarctica, on average, there's water, there's ice that's falling into the ocean, and that's raising the sea level as well.

44The loss of mountain glaciers is accelerating over the last decade, and that is actually giving us about 20% of the sea level rise right now.

45It's just the continued retreat of glaciers in the Rockies, in the Andes, in the Himalayas, in the Alps.

46Pretty much anywhere in the world where we can see ice right now.

47This is probably the most well-known cause of sea level rise.

48Melting ice.

49Right now, 10% of the Earth's surface is covered in ice.

50As the temperature of our planet rises, that ice on average melts.

51Those melted glaciers, icebergs, and ice sheets turn into water that fills our oceans.

52Of course, like most things on Earth, the way our oceans are changing isn't perfectly even.

53Some places are rising quickly, and some are even falling.

54Scientists are looking at coastal places like New Orleans in the United States, and Jakarta in Indonesia, to see how these effects might play out in high-risk areas.

55If sea levels continue to rise, cities and towns that are currently sitting on a coast could find themselves underwater.

56On the other hand, places like Sweden and Greenland are experiencing lowering sea levels.

57The Earth is a fascinating system, and what happens in one place can have strange and far-reaching effects somewhere else.

58So, that three millimeters a year is not uniform.

59You've got effects because of gravity changes.

60This is really cool, you know, mathematically anyway.

61If you lose ice from Antarctica, because that ice is now spread out around the ocean as water, the gravity of the system has changed.

62There's less mass in Antarctica, so there's less gravity.

63And so, the sea level actually falls around Antarctica, but then goes up a little bit more than average everywhere else.

64And the same is true for Greenland.

65If you lose mass on Greenland, it causes the water to go down right next to Greenland, but goes up a little bit further away.

66So you've got these patterns that are associated with gravity, and then even slight shifts in the rotation of the Earth.

67NASA is able to track those shifts and patterns from many different vantage points.

68We have the unique perspective of looking at the Earth, not only from the surface, but from the outside, using planes and orbiting satellites.

69Brooke Medley is a research scientist in NASA's Cryospheric Sciences Laboratory.

70She studies ice melt on the ground and from the skies.

71We really want to understand how the ice is changing now, and then can we use that information to evolve into the next century as sea levels rise across the globe.

72One of the most recent missions that NASA launched is called ICESat-2, and that's a lot of what I'm working on.

73ICESat-2 is an orbiting satellite working as part of NASA's Earth Observing System.

74And the goal of ICESat-2 is to actually measure the changing height of the ice sheets.

75These are very, very thick chunks of ice.

76If we want to understand how they're changing, we can actually measure how they're thickening or thinning.

77And we do that extremely precisely with ICESat-2, down to the millimeter level, because if you have a very subtle change over a very large area, it makes for a really big change.

78ICESat-2 has been orbiting Earth since 2018, at around 300 miles above the surface.

79Even from way up there, ICESat-2 can measure how ice is increasing or decreasing here on Earth.

80The satellite uses a finely tuned instrument that times the travel of laser pulses to measure the elevation of Earth's surface.

81ICESat-2 only has a single instrument on board, and it's its laser altimeter.

82It actually splits that beam into six beams, which gives a much better spatial coverage with every orbit.

83Even though they do a lot of work from the air and space to study Earth, scientists like Brooke are on the ground, too.

84Studying our planet from the ground helps us get a hands-on perspective.

85My job is actually fantastic.

86I love what I do.

87I get to explore Earth's ice, both sitting at my desk solving problems, but also actually going out into the field and observing it.

88I kind of split my time making models and interpreting data, but also spending a lot of time, whether in airplanes flying over the ice sheets or also on the ground actually taking measurements.

89When you're studying ice, you're going to have to spend some time in some pretty cool places.

90And Brooke has had the opportunity to venture far out, where not a lot of people have been able to go.

91The deep field of Earth's coldest continent.

92I've been to Antarctica three times, and it's my absolute favorite place on the planet.

93Antarctica is a very special place.

94You go and you fly into McMurdo, which is a station run by the National Science Foundation.

95It's kind of this little city of like a thousand people right on the coast.

96When you go into the deep field, you take these itty bitty little planes.

97There's just five of us.

98They land.

99They never turn the engine off because they want to make sure that they can fly away again, right?

100So you don't want a plane to get stuck there.

101It's this mad rush to get all your gear off the plane as quickly as possible.

102And then the plane takes off.

103And there you are with five people standing in this flat white nothing in every single direction.

104And it's like exhilarating and terrifying all at once.

105So then the first thing you have to do is, you know, make a fire so that you'll be safe.

106And then you start putting your tents up.

107The one thing that I do remember the most about being there is just it's so quiet.

108I'll never, ever, you know, experience anything where there's just no noise.

109There's no wildlife.

110There's no planes.

111There's no cars.

112There's no people.

113It's just you and you can almost hear your brain working.

114I mean, that's how quiet it is there.

115If you're a scientist and you want to know more about ice melt, sea level rise and climate change, Antarctica is a great place to be.

116It's nearly twice the size of Australia and holds over 90% of all the ice on Earth.

117And that ice can have far reaching effects, not only on the height of the oceans, but on storm surges and flooding events.

118I think the most important thing for people to understand is that sea level rise is predominantly coming from global ice mass loss.

119And that sometimes it might sound like a very small amount, a few millimeters here, an inch, a few inches there.

120And you might think, how is that really going to impact me?

121But I think we have to to remind ourselves of the fact that it's that much more water.

122And when there's a storm, that means there's that much more water that can go further inland.

123It can generate more damage.

124It's not about, hey, your house is going to be underwater now.

125In some places that will be the case.

126It's more about as soon as you put more water into the ocean, storms become that much more catastrophic and start damaging areas that weren't susceptible to floods before.

127So it just means that much more.

128With more water in our oceans, more people will experience the effects of climate change personally.

129Coastal communities are already dealing with the impacts of sea level rise.

130Places like Norfolk, Virginia, are more prone to flooding.

131Areas along the oceans have seen more intense hurricanes.

132In order to prepare for these kinds of events, NASA scientists work on creating computer models of Earth's ecosystems.

133That way they can run different scenarios of how these systems may react to climate change.

134Craig Rye is a research scientist working to map out the unknowns of Antarctica.

135And help predict what will happen as it continues to melt.

136Like Brook, he works on getting different perspectives on the Earth.

137But often from the comfort of his own home.

138My work is centered around trying to understand the Antarctic shelf sea in particular.

139And working on trying to improve our models of the Antarctic shelf sea.

140I spend most of my time in front of a computer trying to debug code.

141Craig Rye is a research scientist.

142In 2020, scientists learned that Antarctica is melting around six times faster than it was only 30 years ago.

143Craig's debugged code will help us predict what could happen if that melting changes or continues at the same rate.

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229The Earth itself is a wild and wonderful place that changes every day.

230And whether it's from 300 miles above the surface, or a lonely tent in the Antarctic wilderness, our capacity for wonder and discovery never ends.

231This is NASA's Curious Universe.

232This episode was written and produced by Christina Dana.

233Our executive producer is Katie Atkinson.

234The Curious Universe team includes Maddie Arnold, Kate Steiner, and Michaela Sosby, with support from Emma Edmond and Priya Mittal.

235Our theme song was composed by Matt Russo and Andrea Santaguida of System Sounds.

236Special thanks to Ellen Gray, Ryland Hegey, Eric Land, Katie Merzman, and the Earth Science News Team.

237If you liked this episode, please let us know by leaving us a review, tweeting about the show at NASA, and sharing with a friend.

238Still curious about NASA?

239You can send us questions about this episode or a previous one, and we'll try to track down the answers.

240You can email a voice recording or send a written note to NASA-CuriousUniverse at mail.nasa.gov.

241Go to NASA.gov slash curious universe for more information.

242Wonderful.

243Well, anything else you think we should cover?

244Anything I've missed?

245I could talk about this stuff for days.

246So don't ask me that.

247I could talk about this.

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