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What’s hidden under the Greenland ice sheet? | Kristin Poinar

What’s hidden under the Greenland ice sheet? | Kristin Poinar


When was I was 21 years old, I had all this physics homework. Physics homework requires taking breaks, and Wikipedia was relatively new,
so I took a lot of breaks there. I kept going back to the same articles, reading them again and again, on glaciers, Antarctica and Greenland. How cool would it be to visit these places and what would it take to do so? Well, here we are on a repurposed Air Force cargo plane operated by NASA flying over the Greenland ice sheet. There’s a lot to see here, but there’s more that is hidden, waiting to be uncovered. What the Wikipedia articles didn’t tell me is that there’s liquid water
hidden inside the ice sheet, because we didn’t know that yet. I did learn on Wikipedia
that the Greenland ice sheet is huge, the size of Mexico, and its ice from top to bottom
is two miles thick. But it’s not just static. The ice flows like a river
downhill towards the ocean. As it flows around bends, it deforms and cracks. I get to study these amazing ice dynamics, which are located in one of the most
remote physical environments remaining on earth. To work in glaciology right now
is like getting in on the ground floor at Facebook in the 2000s. (Laughter) Our capability to fly airplanes
and satellites over the ice sheets is revolutionizing glaciology. It’s just starting to do for science what the smartphone
has done for social media. The satellites are reporting
a wealth of observations that are revealing new hidden facts
about the ice sheets continuously. For instance, we have observations
of the size of the Greenland ice sheet every month going back to 2002. You can look towards the bottom
of the screen here to see the month and the year go forward. You can see that some areas
of the ice sheet melt or lose ice in the summer. Other areas experience snowfall or gain ice back in the winter. This seasonal cycle, though, is eclipsed
by an overall rate of mass loss that would have stunned
a glaciologist 50 years ago. We never thought that an ice sheet could
lose mass into the ocean this quickly. Since these measurements began in 2002, the ice sheet has lost so much ice that if that water were piled up
on our smallest continent, it would drown Australia knee-deep. How is this possible? Well, under the ice lies the bedrock. We used radar to image the hills,
valleys, mountains and depressions that the ice flows over. Hidden under the ice sheet are channels
the size of the Grand Canyon that funnel ice and water
off of Greenland and into the ocean. The reason that radar
can reveal the bedrock is that ice is entirely
transparent to radar. You can do an experiment. Go home and put
an ice cube in the microwave. It won’t melt, because microwaves, or radar, pass straight through the ice
without interacting. If you want to melt your ice cube,
you have to get it wet, because water heats up easily
in the microwave. That’s the whole principle
the microwave oven is designed around. Radar can see water. And radar has revealed
a vast pool of liquid water hidden under my colleague Olivia, seven stories beneath her feet. Here, she’s used a pump to bring some of that water
back to the ice sheet’s surface. Just six years ago, we had no idea
this glacier aquifer existed. The aquifer formed when snow melts in the summer sun and trickles downward. It puddles up in huge pools. From there, the snow acts as an igloo, insulating this water
from the cold and the wind above. So the water can stay
hidden in the ice sheet in liquid form year after year. The question is, what happens next? Does the water stay there forever? It could. Or does it find a way out
to reach the global ocean? One possible way
for the water to reach the bedrock and from there the ocean is a crevasse, or a crack in the ice. When cracks fill with water, the weight of the water
forces them deeper and deeper. This is how fracking works to extract natural gas
from deep within the earth. Pressurized fluids fracture rocks. All it takes is a crack to get started. Well, we recently discovered that there are cracks available
in the Greenland ice sheet near this glacier aquifer. You can fly over
most of the Greenland ice sheet and see nothing, no cracks, no features on the surface, but as this helicopter
flies towards the coast, the path that water would take
on its quest to flow downhill, one crack appears, then another and another. Are these cracks filled with liquid water? And if so, how deep
do they take that water? Can they take it to the bedrock and the ocean? To answer these questions, we need something
beyond remote sensing data. We need numeric models. I write numeric models
that run on supercomputers. A numeric model
is simply a set of equations that works together to describe something. It can be as simple
as the next number in a sequence — one, three, five, seven — or it can be a more complex
set of equations that predict the future based on known conditions in the present. In our case, what are
the equations for how ice cracks? Well, engineers already have
a very good understanding of how aluminum, steel and plastics
fracture under stress. It’s an important problem in our society. And it turns out
that the engineering equations for how materials fracture are not that different
from my physics homework. So I borrowed them, adapted them for ice, and then I had a numeric model
for how a crevasse can fracture when filled with water from the aquifer. This is the power of math. It can help us understand
real processes in our world. I’ll show you now
the results of my numeric model, but first I should point out that the crevasse is about
a thousand times narrower than it is deep, so in the main panel here, we’ve zoomed in to better see the details. You can look to the smaller
panel on the right to see the true scale
for how tall and skinny the crevasse is. As the aquifer water
flows into the crevasse, some of it refreezes
in the negative 15 degree Celsius ice. That’s about as cold
as your kitchen freezer. But this loss can be overcome if the flow rate in from
the glacier aquifer is high enough. In our case, it is, and the aquifer water drives the crevasse
all the way to the base of the ice sheet a thousand meters below. From there, it has a clear path
to reach the ocean. So the aquifer water is a part of the three millimeters
per year of sea level rise that we experience as a global society. But there’s more: the aquifer water
might be punching above its weight. The ice flows in complex ways. In some places, the ice flows very fast. There tends to be water
at the base of the ice sheet here. In other places, not so fast. Usually, there’s not water
present at the base there. Now that we know the aquifer water
is getting to the base of the ice sheet, the next question is: Is it making the ice itself
flow faster into the ocean? We’re trying to uncover these mysteries
hidden inside the Greenland ice sheet so that we can better plan
for the sea level rise it holds. The amount of ice
that Greenland has lost since 2002 is just a small fraction
of what that ice sheet holds. Ice sheets are immense, powerful machines
that operate on long timescales. In the next 80 years, global sea levels
will rise at least 20 centimeters, perhaps as much as one meter, and maybe more. Our understanding
of future sea level rise is good, but our projections have a wide range. It’s our role as glaciologists
and scientists to narrow these uncertainties. How much sea level rise is coming, and how fast will it get here? We need to know how much and how fast, so the world and its communities can
plan for the sea level rise that’s coming. Thank you. (Applause)

Comments (74)

  1. Always wanted beach front property.
    From the top of Texas! LOL

  2. Sea levels rise but they also fall sea level falling during a certain season of the year is not being explained here so you are not getting both sides of this story the sea levels and their tides will always adjust themselves as they always have nothing is going to change. When Miami is underwater then I'll believe you.

  3. Well, judging by all the bushit global warming scaremonger predictions thats already proven to be bullshit, I think its safe to assume their computer models are bullshit too.

    And no dearest eco tards. No amount of cool air taxes, rammed down the throats of the least polluting nations will solve the "problem".

  4. Under the greenland ice sheet? Area 52

  5. Maybe they're the same super computers that didn't predict the financial horror story of 2008, it took a handful of humans, notably Nouriel Roubini, the footage of the IMF audibly laughing at him at a conference in 2006 as he gives his doomsday speech can be found on this very platform, so please, don't quote 'Supercomputer' at me. A taxi cab driver has a better record of predicting long term economic trends than an Ivy league economist.

  6. Actually scrub that last comment, any scientist that uses "we know" should be removed from the science community. Physics, chemistry, biology, all constantly evolving sciences, let's add a religion to that community of sciences.

  7. Choclate Pudding lots of Choclate Pudding and Jam Donuts thats what is under their i have seen it, just make sure you take your Spoon and Desert Dish its the best

  8. it is the Mummy of Trumps grandmother

  9. According to AOC. She tweeted on her Twitter account if the ice caps melt they could release vampire or zombie viruses. The fact she is in the US Congress is an indictment on the educational system of this country!

  10. We're doomed as Capitalist societies. We just won't stop burning fossil fuels and our timing is already past critical mass. All we can do as a "Manhattan Project" now,…is slightly slow down the inevitable.

    Man wants 300 hp automobiles….or even just having 300,000,000 Toyota Prius's wouldn't change anything at this point.

    The Illuminati have "stated", that we should have a major war and kill of 4-5 billions of people…to slow down what's happening now; keep their' family dominance and continue on…off the backs of the Poor and Middle Class as usual.

    Logic states that this is "an actual good answer"….it appears that the Russians/Chinese and Americans are close to WWIII now; according to the statistics which happen to match up with the Book of Revelations anyhow.

    So,…all one can do as an individual now…is realize that God's Son will be visiting again soon…and that we should do what we can for individuals to help other individuals.

    First, have Jesus Christ as your Savior…not the "Moon God", Allah (False God) or some Statue of a Sacred Cow (for God's sake!).

    There can only be one true God…and he visited the earth some 2,000 years ago and died for us,…that we may join him in Heaven later. Choose wisely and choose soon!

  11. sure a lot of theorizing …and a lot of bogus science too …its global-warming fear mongering …and God said He would never flood the world again anyways …its the Yellowstone caldera and Wormwood asteroid we gotta worry about …not global warming

  12. 80years.. couple feet of water.. MEH

  13. Don’t tell Nestle They will suck it into Bottles and send it to Saudi Arabia

  14. Boring Boring Boring, the sea lever could rise 20cm so we have to prepare our self……for what?

  15. She's lying. The sea level is not rising as she states because global warming is a globalist hoax.

  16. I am calling BS on this….my uncle was in the US Corp and they found water in 1954…..

  17. Kristin – – Intelligence + Heat Factor approaching 10 = I'm in love..lol

  18. answer: The United States

  19. This is the most boring Ted Talk I have ever seen. Just eat at McDonalds everyday lady you look like you got cancer.

  20. why is she soo hot!?!?

  21. What's under Greenland? Trump's foot I think

  22. There is water on Greenland? Wow, and there is water under the ocean too.

  23. The sky is falling, the sky is falling. Chicken Little is no different than the boy who cried wolf. Natural sun cycles effect the climate way more than man could ever do. Let the ice melt and return later.

  24. What's under the Greenland ice sheet? Not the lost tribe of Dan, that's for sure. I heard Elon Musk is hiding them on Mars

  25. But microwave and radio waves are 2 different wavelengths… Hmmmm

  26. Did the US in all its arrogant ways of considering othere ,"Minor" states, like the Danish/Inuit : ever get permission to survey the Greenland airspace? We know that the US frequently violates the Waters, where Greenland possesses national supremacy!!

  27. The Greenland ice sheet is growing 300 metre's thicker in two years explain that Mr's

  28. We need to find a way to melt all the ice. Would be great for hiking biking and camping. Trump is going to buy Greenland. I hope he hires me to work there. We have to melt all that horrible ice, just saying.

  29. Absolute BS. This woman is making predictions for which she has absolutely NO proof. She is obviously using the fraudulent math models of the UN's IPCC to predict Global Warming. None of these models is based on science but on the political desire of some to overturn current world governments.

    The Great Global Warming Swindle
    https://www.youtube.com/watch?v=52Mx0_8YEtg

    The World In Midst of Carbon Drought (w/ Prof. William Happer, Princeton University)
    https://www.youtube.com/watch?v=U-9UlF8hkhs

    A Funny Thing Happened on the Way to Global Warming
    https://www.youtube.com/watch?v=RZlICdawHRA&t=793s

    Scientist Destroys Libs Argument about Climate Change Models
    https://www.westernjournal.com/ct/actual-scientist-climate-change/?utm_source=Facebook&utm_medium=PostSideSharingButtons

  30. Trump's real hair is under there,that's why he wants to buy it

  31. Great! Maybee we can plant crops again there like there was during the Midevil warming period 1000 years ago! Good news!

  32. What's under the Greenland ice?
    Soil.
    When was it deposited and when did layer upon layer of snow pile up?

  33. So many problems with this: "So the aquifer is a part of the 3 millimeters per year, of sea level rise that we experience as a global society" – Did you catch the propaganda innuendo? Are you, my global society members experiencing this? Didn't think so. And btw, all ice melt and rain fall ultimately makes it's way to the oceans. This is designed for new kids who didn't learn real science. Also… her mathematical models are built using a LOT of assumptions. So spread "knee deep water the size of Australia" around all the oceans and get… maybe another millimeter?. The real question is WHY are they selling these ideas so hard?

  34. the army new there was water under the ice sheets back in the 50's when they built camp century

  35. What about the coming ice age? Energy shortages? Global famines. Oops that's what was predicted in the 1970's.. this is all bs. Science can change any model they want.

  36. There is way too many " i dont knows" within the science community. She went from 20cm to 1m in 20 years.. What happened to the world ending in 12 years? There is something somewhere in science that is wrong and has spiraled out of control.. Ancient theories physics and math was way superior.. Where is the 1 wrong thing we all think is right? This makes no sense… Roman concrete is superior to all.. The way they cut stone for the pyramids is superior to all… Apparently Nikola Tesla had the technology to harness free energy.. So with all these therioes and conclusions in science something is not adding up..

  37. Well, someone could buy Greenland and use a wall that they dont need anywhere else, to keep the water in!

  38. I just melted an ice in tha microwave ….lol…

  39. measurement began in 2002.so we really dont know .

  40. she is just regurgitating

  41. science is just religion now.scientists just constantly lie

  42. she is just lying.its all speculation

  43. Hope this doesn't mean that the Obama's new beach front home will be under water ! Make Greenland Green Again !

  44. It’s like getting-in on the ground floor of FB, except there are no selfies or money.

  45. Superman’s cave of solitude is also located here. Superheroes can't fight crime and save lives around the clock. Sometimes they need a place to go to get away from it all, a place that is all their own, where they can relax and do the things they want to do.

  46. Space ships ailens green boogers

  47. doing what humans have always done, adapt to change. Using fear of change to extract $$ from our pockets is political/corporate greed.

  48. The Vikings swapped names between Greenland and Iceland to fool invaders – who, upon landing in Greenland discovered it was mostly Ice and that Iceland was likely the same (which it is not) The end result? The invaders moved on, arriving at North America long before Christopher Columbus, leaving volcanic Iceland to Icelanders and frozen Greenland to the Inuits. Tectonically, Greenland is part of the North American plate but is geographically closer to Canada than the USA – you hearing this Justin? Greenland – Canada's 11th Province makes more sense than becoming a US territory or her 51st State. I don't think the Danes would like that – and rightly so – leave Greenland be Captain America – she don't belong to you and hopefully never will.

  49. What's hidden under this transgenders dress?

  50. Let's think about this moment. According to the science of calculus, if a snug belt were over the equator – and was increased in length by 7 feet.- could you crawl under it? Yes. So that's the science of calculus. So let's think about the geophysics of this- a bit more complex.

  51. Corn Fields, that the Vikings Planted. Why do you think the Vikings called it Greenland, if it was totally Frozen and covered in Snow and Ice? They left when the Climate Changed, it when from Green to Frozen Over.

  52. I live near the ocean and it is the same level now that it was 45 years ago so maybe the ice sheet has always flowed like this

  53. Genesis 7:11 (another example of science proving the word of God. 😉

  54. Partly informative, mainly NASA globe earth propaganda..

  55. Great talk! Very informative and pedagogic!

  56. Rocks, ice, Greenland…Zzzzz

  57. “Waiting to be uncovered”
    The chemtrails are warming the planet to melt the Greenland sheet and scare the world into accepting one world government.
    The USA wants the natural resources under the ice.

  58. As soon as the word NASA was used, I'm out. Liars.

  59. but you dont know what the future is. if it gets colder, then the glaciers will store more water and the ocean will drop.

  60. Go down to the ocean and you'll realize that the seas are NOT rising as this alarmist is claiming. Why? Because the REAL oceans DON'T use computers!!! Think about it.

  61. Kristin Poinar, the earth DOESN'T use computers so predicting Climate Change with a computer only means that your prejudices are the Climate Change not the real Climate.

  62. Kristin, Good luck with your computer predictions however do NOT rely on them to predict Climate Change – which is what you are really trying to convince us of.

  63. Kristin, howzabout one of the inventors of Climate Change – Barry the Fairy Obama?

    "Now is the time when the seas will lower…or something."–Barack O'Stupid claiming to be Jesus in 2008.

    If you side with that moron then will it Doom Obama’s new Martha’s Vineyard mansion?

  64. Why worry over the inevitable… Everything ends, Sun's, Planets, Plant Life, Animal Life… Human Life. Even the Universe as a whole will end and we will never change that, just enjoy the miniscule amount of time you have at being alive.

  65. Making money from natural environmental changes.so sad but the plebs will pay👏👏👏

  66. Shutup n bend over

  67. "What's hidden under the Greenland ice sheet?"
    Everyone who's watched the Young Pope already knows the answer to this question!

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