HomeНовости и политикаRelated VideosMore From: Climate State

Eric Rignot: Ice Sheet Systems and Sea Level Change (Sea level rise)

54 ratings | 4689 views
Scientific Discipline: Cryosphere Speaker: Eric Rignot (NASA Jet Propulsion Laboratory) Abstract Modern views of ice sheets provided by satellites, airborne surveys, in situ data and paleoclimate records while transformative of glaciology have not fundamentally changed concerns about ice sheet stability and collapse that emerged in the 1970's. Motivated by the desire to learn more about ice sheets using new technologies, we stumbled on an unexplored field of science and witnessed surprising changes before realizing that most were coming too fast, soon and large. Ice sheets are integrant part of the Earth system; they interact vigorously with the atmosphere and the oceans, yet most of this interaction is not part of current global climate models. Since we have never witnessed the collapse of a marine ice sheet, observations and exploration remain critical sentinels. At present, these observations suggest that Antarctica and Greenland have been launched into a path of multi-meter sea level rise caused by rapid climate warming. While the current loss of ice sheet mass to the ocean remains a trickle, every mm of sea level change will take centuries of climate reversal to get back, several major marine-terminating sectors have been pushed out of equilibrium, and ice shelves are irremediably being lost. As glaciers retreat from their salty, warm, oceanic margins, they will melt away and retreat slower, but concerns remain about sea level change from vastly marine-based sectors: 2-m sea level equivalent in Greenland and 23-m in Antarctica. Significant changes affect 2/4 marine-based sectors in Greenland - Jakobshavn Isbræ. and the northeast stream - with Petermann Gl. not far behind. Major changes have affected the Amundsen Sea sector of West Antarctica since the 1980s. Smaller yet significant changes affect the marine-based Wilkes Land sector of East Antarctica, a reminder that not all marine-based ice is in West Antarctica. Major advances in reducing uncertainties in sea level projections will require massive, interdisciplinary efforts that are not currently in place but are getting there. Projection scenarios are overwhelmingly conservative, pushed up by observations, awaiting more detailed knowledge of ocean circulation, winds, ice-ocean interaction, and mechanics of rapid ice fracture, not to mention the mere definition of static boundaries (ice thickness and sea floor bathymetry). https://agu.confex.com/agu/fm15/meetingapp.cgi/Paper/60094 Related The John F. Nye Lecture http://cryosphere.agu.org/nye-lecture-series/
Html code for embedding videos on your blog
Text Comments (20)
Frank Reiser M.S. (2 years ago)
Great video! It is people like you that I have made my own videos (Frank Reiser M.S.) Show more! Sincerely, Frank Frank's Beautiful Rocks and Minerals
Natures Peace (2 years ago)
This is awesome. A 55 year record of the ice sheets and still can't do a damn thing to prevent total collapse. Thanks guys. Let's keep on that close watch.
grindupBaker (2 years ago)
+Autism Awareness Well sort of yes. That's because it would have been necessary to stop burning carbon as the energy source for humans and that was totally impractical to do instantly. Humans made a choice to make no attempt to stop burning carbon gradually over a few decades. That's a clear choice that humans made. So it isn't quite "can't do a damn thing to prevent", it's that humans don't want to.
Whirled Publishing (2 years ago)
+Autism Awareness They can't prevent it - but if you want to survive the hell and horror that's coming, you can pack and leave.
AffordYourNuance (2 years ago)
One thing I never hear addressed when people proclaim, "but ice cover is increasing!". Is that the run-off from the glaciers is mostly fresh water and has a lower freezing temperature than salt water and so can help form ice sheets on short time-scales. I mean, maybe I am wrong, I am not a scientist. Is what I said a valid analysis of what could be happening?
grindupBaker (2 years ago)
+grindupBaker If there has been increased precipitation (there's 4% more water in the air due to global warming) that would freshen the antarctic ocean directly and more snow on Antarctica would cause a low mass balance change with a higher increased ice loss into the ocean (it evaporates from tropical regions and rains elsewhere).
grindupBaker (2 years ago)
+Krath That's one of the two possibilities. Apparently, ~103 km**3 / year has been melting off Antarctica. That's 113,000 km**2 at the 1 metre thickness. However, Eric graph shows ~610,000 km**2 "sea ice extent" increase 1979-2012 so mass loss is only 18% of the increase. However, I just realized that mass loss is only the same as runoff if there's no change in precipitation. I can't find it offhand and I need to move on. See posting circa March 2010 last update 8 July 2015 "Why is southern sea ice increasing?" on the sks site. Second possibility, there's a convention that if the data cell (a unit of area seen by the satellite such 25 km x 25 km) has greater than 15% ice concentration, the cell is considered "ice covered". So "sea ice extent" does not mean "ice area". Sea with 15% ice lumps floating in it is all included. The Antarctic Westerlies have increased 30% this talk says. That will blow the ice out over a larger area giving higher "sea ice extent" for the same ice. Also, stronger wind will open more water to the surface exposing it to freezing temperature of air. Ice insulates the water below somewhat. Increasing winds must be a big factor in higher "sea ice extent".
Alfred Adrian,Jr. (2 years ago)
+Krath Yes, that is right. Sea water is about 35 parts salt per 1000 so it freezes at about 3 and 1/2 F (3.6 F) lower than fresh water. The significance of this to climate change is that it it leads to more ice cover around Antarctica. Paradoxically this in turn leads to retention of heat in the ocean and increased erosion of the tongues of ice which spread out from land based glaciers. Essentially, the lens of fresh water which freezes more easily stops the emission of heat to space from the southern ocean. This additional heat then erodes from the bottom the tongues or ice shelves and permits more rapid movement of land based glacial ice into the sea. This is Hansen's primary contribution in his last paper and bolsters his argument that the tropics will now begin to heat more rapidly with the consequent development of a large temperature gradient in the Atlantic as the deep water conveyor slows. Sandy's power was in part due to this effect. If the AMOC shuts down as Hansen believes it will sometime in the not too distant future we are fucked as future storms will be much more potent than Sandy. Additionally, as explained by Hansen we now have a further mechanism which supports the contention already revealed by a short GRACE satellite data set that the ice sheets will disintegrate much faster than our current models predict.....it will be nonlinear. We are in a world of hurt. There is some evidence that the doubling time of sea level rise is SEVEN years according to some AMEG members. Hansen hedges his bet and is still hopeful that it is 10 or 20 years. If it goes exponential, which it apparently is doing, we are totally SCREWED IN EITHER CASE. On top of all of this is the methane emission from the ESAS that has been extensively studied by Shakhova who thinks a 50Gton emission is eminent. Do you ever feel like you are trapped in some sort of bad sci-fi novel? http://antoine.frostburg.edu/chem/senese/101/solutions/faq/why-salt-melts-ice.shtml http://www.slate.com/blogs/the_slatest/2016/03/22/james_hansen_sea_level_rise_climate_warning_passes_peer_review.html http://rsta.royalsocietypublishing.org/content/373/2052/20140451
Whirled Publishing (2 years ago)
Altimetry readings are misleading - an increase in the elevations of the glaciers are insufficient evidence to claim the glaciers are increasing in size: Glaciers around the world are rapidly melting - glacial rebound may result in higher elevation readings of the glaciers - which is the most likely cause for the higher altimetry readings in Antarctica. In other words, there is no evidence that the glaciers in Antarctica are growing. The evidence strongly suggests that all glaciers are rapidly melting. Anomaly maps show unusually high volumes of glacial melt all around Antarctica, south of Greenland, south of the Russian glaciers, etc.: http://polar.ncep.noaa.gov/sst/ophi/color_newdisp_anomaly_global_lat_lon_ophi0.png http://pamola.um.maine.edu/fcst_frames/GFS-025deg/DailySummary/GFS-025deg_WORLD-CED_T2_anom.jpg
Whirled Publishing (2 years ago)
+grindupBaker I monitor hot spots around the world - for the purposes of monitoring glacial melt. The resulting ice shelf collapses and glacier crashes will cause horrific damage. Seismic monitors are all across Greenland and Antarctica but all that data is hidden from us - including the volcanic data - sorry.
grindupBaker (2 years ago)
I was referring only to geothermal heat analyses like the one I found and gave (volcanoes or regular geothermal). I didn't really make that clear.
Whirled Publishing (2 years ago)
+grindupBaker The question is: how high will the tsunami waves be? How big are the glaciers that will crash into the sea? the largest glaciers are approximately 46,000 miles squared weight: billions of tons distance dropped: 20 feet for the Ross Ice shelf (90% of the ice shelves are underwater) I'll see if I can get the maximum depth of the Amundsen Sea, the Ross Sea, Bellinghausen Sea and Weddell Sea - in some places the sea waters are surprisingly shallow - the tsunami wave heights from there won't be as high as they would be if the seas were miles deep there. I'm still researching the height of the ice shelves in Amundsen Sea - as some of the biggest most vulnerable glaciers are there - I know Totten Glacier is massive but most of it rests on land - not on an ice shelf - so I am not expecting a massive tsunami wave from Totten Glacier Based on the info above, perhaps you can let me know the height of the tsunami waves in your calculations. Those who want to survive want to know how high up the mountain they should be - I would appreciate more input on this question.
Whirled Publishing (2 years ago)
+grindupBaker As I said, some of the Antarctic glaciers are the size of Pennsylvania, twice the size of Tasmania, larger than Portugal, etc. - although the entire glacier may not collapse into the sea all at once. I have done calculations for the height of the resulting displacement tsunami waves - but I would be happy to see what you come up with. This is a map of the ice shelves and glaciers to help give you an understanding of the impact this devastation will have on our world: https://www.nasa.gov/sites/default/files/images/755402main_earth20130613b-full.jpg P.S. I already packed and left North America. The chances of surviving there will be next to zero. I upload my climate updates and climate forecasts - along with thousands of links to the data from around the world which I translate from over a dozen languages. Anyone who wants the truth can find it - people contact me from all around the world - unfortunately, most people are content with the lies they get from the whores.
Whirled Publishing (2 years ago)
+grindupBaker Sea level rise forecasts - which are published by glaciologists - are all wrong. Sea level rise will happen much sooner than the public is being told and sea level rise will rapidly escalate - far beyond their forecasts - because glaciologists are apparently in denial of four factors: 1) Rapid glacial melt is being caused by a dramatic increase in volcanic activity - below the ice and snow of Greenland and Antarctica and on the sea floors all around the shores of the Arctic and Antarctic ice sheets. 2) As glacial melt flows into the sea, it only takes a few months for ocean currents to carry the glacial melt to equatorial regions where temperatures are 80 F / 26.6 C which means thermal expansion only takes a few months. 3) Rapid sea level rise has been kept to a minimum because our oceans are so unusually warm in many regions which results in rapid evaporation and ultimately results in record rainfall and torrential downpours in nearby low-pressure systems - in other words: Sea Level Rise Is Coming From the Skies "Experts" and the public fail to acknowledge this obvious fact. Sea level rise has been increasing due to rapid glacial melt which is the result of the heat from volcanic eruptions. 4) If volcanic eruptions continue to escalate - and the climate data strongly suggests they will - oceans will continue to warm up which will result in the rapid collapse of the ice shelves while simultaneously resulting in more record-rainfall around the world. As ice shelves and glaciers collapse, colossal tsunami waves will decimate our world - billions of people will be killed and lethal radiation poisoning will make the northern hemisphere uninhabitable. Even with all the glacial water, the oceans may continue to warm up which means thermal expansion rates for the Arctic Ocean, the Antarctic waters and all the other waters below 26.6 F - this is why thermal expansion will - most likely - result in much higher and much more rapid sea level rise than the experts have forecast. Colossal tsunami waves will - most likely - decimate our world, followed by rapid sea level rise. The precedence for this is documented in historic records from around the world - which is summarized in my April and May videos. I estimate about 50 glaciers will collapse into the seas around Antarctica - each of those 50 glaciers will launch colossal tsunami waves. The ice shelves and glaciers in Antarctica will decimate northern Europe, the UK, etc. Even the Mediterranean Sea will be impacted. I will provide a link to a map of the Antarctic ice shelves and glaciers in a follow up reply.

Would you like to comment?

Join YouTube for a free account, or sign in if you are already a member.