First results from NASA’s ICESat-2 mission map 16 years of melting ice sheets

University of Washington

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IMAGE: This shows the amount of ice gained or lost by Antarctica between 2003 and 2019. Dark reds and purples show large average rates of ice loss near the coasts, while… view more  Credit: Smith et al./Science

Using the most advanced Earth-observing laser instrument NASA has ever flown in space, a team of scientists led by the University of Washington has made precise measurements of how the Greenland and Antarctic ice sheets have changed over 16 years.

In a new study published in the journal Science on April 30, scientists found the net loss of ice from Antarctica, along with Greenland’s shrinking ice sheet, has been responsible for 0.55 inches (14 millimeters) of sea level rise to the global ocean since 2003. In Antarctica, sea level rise is being driven by the loss of the floating ice shelves melting in a warming ocean. The ice shelves help hold back the flow of land-based ice into the ocean.

The findings come from the Ice, Cloud and land Elevation Satellite 2 (ICESat-2), which was launched into orbit in fall 2018 and began taking detailed global elevation measurements, including over Earth’s frozen regions. By comparing the new data with measurements taken by the original ICESat from 2003 to 2009, researchers have generated a comprehensive portrait of the complexities of ice sheet change – and insights into the future of Greenland and Antarctica.

“If you watch a glacier or ice sheet for a month, or a year, you’re not going to learn much about what the climate is doing to it,” said lead author Benjamin Smith, a glaciologist at the University of Washington. “We now have a 16-year span between ICESat and ICESat-2 and can be much more confident that the changes we’re seeing in the ice have to do with the long-term changes in the climate. And ICESat-2 is a really remarkable tool for making these measurements. We’re seeing high-quality measurements that carpet both ice sheets, which let us make a detailed and precise comparison with the ICESat data.”

Previous studies of ice loss or gain often analyze data from multiple satellites and airborne missions. The new study takes a single type of measurement – height as measured by an instrument that bounces laser pulses off the ice surface – providing the most detailed and accurate picture of ice sheet change to date.

The researchers took tracks of ICESat measurements and overlaid the denser tracks of ICESat-2 measurements from 2019. Where the two data sets intersected – tens of millions of sites – they ran the data through computer programs that accounted for the snow density and other factors, and then calculated the mass of ice lost or gained.

“The new analysis reveals the ice sheets’ response to changes in climate with unprecedented detail, revealing clues as to why and how the ice sheets are reacting the way they are”, said co-author Alex Gardner, a glaciologist at NASA’s Jet Propulsion Laboratory in Pasadena, California.

The study found that Greenland’s ice sheet lost an average of 200 gigatons of ice per year, and Antarctica’s ice sheet lost an average of 118 gigatons of ice per year. One gigaton of ice is enough to fill 400,000 Olympic-sized swimming pools.

Of the sea level rise that resulted from ice sheet meltwater and iceberg calving, about two-thirds of it came Greenland, the other third from Antarctica, Smith and his colleagues found.

“It was amazing to see how good the ICESat-2 data looked, right out of the gate,” said co-author Tom Neumann at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “These first results looking at land ice confirm the consensus from other research groups, but they also let us look at the details of change in individual glaciers and ice shelves at the same time.”

In Greenland, there was a significant amount of thinning of coastal glaciers, Smith said. The Kangerlussuaq and Jakobshavn glaciers, for example, have lost 14 to 20 feet (4 to 6 meters) of elevation per year. Warmer summer temperatures have melted ice from the surface of the glaciers and ice sheets, and in some places warmer ocean water erodes away the ice at their fronts.

In Antarctica, the dense tracks of ICESat-2 measurements showed that the ice sheet is getting thicker in parts of the continent’s interior, likely as a result of increased snowfall, Smith said. But the loss of ice from the continent’s margins, especially in West Antarctica and the Antarctic Peninsula, far outweighs any gains in the interior. In those places, the ocean is also likely to blame.

“In West Antarctica, we’re seeing a lot of glaciers thinning very rapidly,” Smith said. “There are ice shelves at the downstream end of those glaciers, floating on water. And those ice shelves are thinning, letting more ice flow out into the ocean as the warmer water erodes the ice.”

These ice shelves, which rise and fall with the tides, can be difficult to measure, said co-author Helen Amanda Fricker, a glaciologist at Scripps Institution of Oceanography at the University of California, San Diego. Some of them have rough surfaces, with crevasses and ridges, but the precision and high resolution of ICESat-2 allows researchers to measure overall changes, without worrying about these features skewing the results.

This is one of the first times that researchers have measured loss of the floating ice shelves around Antarctica simultaneously with loss of the continent’s ice sheet.

Ice that melts from ice shelves doesn’t raise sea levels, since it’s already floating – just like an ice cube in a full cup of water doesn’t overflow the glass. But the ice shelves do provide stability for the glaciers and ice sheets behind them.

“It’s like an architectural buttress that holds up a cathedral,” Fricker said. “The ice shelves hold the ice sheet up. If you take away the ice shelves, or even if you thin them, you’re reducing that buttressing force, so the grounded ice can flow faster.”

The researchers found ice shelves in West Antarctica, where many of the continent’s fastest-moving glaciers are located, are losing mass. Patterns of thinning show that Thwaites and Crosson ice shelves have thinned the most, an average of about five meters (16 feet) and three meters (10 feet) of ice per year, respectively.

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The study was funded by NASA. Other co-authors are Johan Nilsson and Fernando Paolo at NASA’s Jet Propulsion Laboratory; Brooke Medley, Thorsten Markus and H. Jay Zwally at NASA’s Goddard Space Flight Center; Nicholas Holschuh at Amherst College; Susheel Adusumilli at the University of California, San Diego; Kelly Brunt at the University of Maryland; Bea Csatho at the University of Buffalo; Kaitlin Harbeck at KBR; and Matthew Siegfried at the Colorado School of Mines.

From EurekAlert!

112 thoughts on “First results from NASA’s ICESat-2 mission map 16 years of melting ice sheets

  1. “We now have a 16-year span between ICESat and ICESat-2 and can be much more confident that the changes we’re seeing in the ice have to do with the long-term changes in the climate.”

    16 years worth of data is enough to see long term changes in climate? It’s scarcely enough to define the present climate, let alone determining it’s different to usual.. Let alone extrapolating into the future..

    • !4 mm of sea level rise due to ice melt is less than 1mm per year.

      Does that mean that satellite data on sea level rise is not accurate and overstated, or does it mean that sea level rise has infact been slowing these past 16 years?

      Does changes in total ocean heat content (a figure not really known) these past 16 years, plus the 14mm from Antarctic/Arctic ice loss support the satellite data for sea level rise these past 16 years?

      Whatever the answers to those questions are, it is clear that 14mm every 16 years is not alarming such that if the present rate of ice melt continues for the next 80 years, we ought not be troubled by sea level rise. NYC will not be under water anytime soon.

      • Flying from London to Auckland is 24 hours plus minus always over water 1 mm a year???? How to calculate storms tides etc my ignorance is bliss.

      • Under water soon? At this rate, Antarctica will be ice free in just over 200,000 years, provided the warm(er) ocean can reach into the interior.

        As is shown by the satellite imagery, the East side is increasing the thickness. That has been known for a while and “blamed” on global warming.

        From the pair of net sources of water, the loss from Greenland and Antarctica matches claimed measures of sea level rise (1.8mm/year). This rate is well known and hasn’t changed in decades. Has it changed since 1850? No. Same as always. At the present rate, in 1000 years sea level will be where it was during the Roman optimum. *Yawn*

        • Agreed Crispin!
          This Antarctica graphic is intended to artificially cause fear.

          Check out the legend.
          Vast areas of Antarctica are gaining ice.
          Miniscule areas near certain coasts are losing ice.

          Whenever a graphic displays minor and major areas. Yet their legend is overwhelmingly biased towards displaying the minor area losing ice metrics.
          Neither plus/minus portions of the legend are detailed, so an observer can identify specific color represent specific ice gains losses.

          Meaning the Antarctica image is specifically designed to highlight ice loss with preference given towards alleged massive ice losses not actually displayed in Antarctica, but those displayed along the very edges of Antarctica’s West Coast

          Given NOAA’s biases, and the bizarre slant of this graphic, odds are those losses are statistically smudged inland from the coasts.

          Sea ice tidal changes are used to increase inland ice losses.

          “In Antarctica, sea level rise is being driven by the loss of the floating ice shelves melting in a warming ocean.”

          Floating ice only shows a small portion of the ice above water.
          Grounded floating ice is not as “grounded” as the glaciers flowing down to the oceans.

          “The new study takes a single type of measurement – height as measured by an instrument that bounces laser pulses off the ice surface – providing the most detailed and accurate picture of ice sheet change to date.”

          Making parts of the researcher’s claim base fantasies. e.g.:

          “In Antarctica, sea level rise is being driven by the loss of the floating ice shelves melting in a warming ocean. The ice shelves help hold back the flow of land-based ice into the ocean.”

          “In Antarctica, the dense tracks of ICESat-2 measurements showed that the ice sheet is getting thicker in parts of the continent’s interior, likely as a result of increased snowfall, Smith said.”

          “Likely”!?
          In spite of the researcher’s claims, ice accretions over vast areas easily exceed large losses over extremely small areas.

          • All these graphics are confected to cause fear. They are the equivalent of viewing the world through a drinking straw or some sort of micro camera like the doctors insert in you and when you come across an ant or fly or even a flea, start shoulding ‘monsters from Mars!!!’

            This sort of stuff is targetted at ecoloons. Its like making alfoil hats for paranoid iceheads.

        • Seriously, Greenland could be green again, like the Viking days, a northern outdoor paradise.

      • One gigaton of ice is enough to fill 400,000 Olympic-sized swimming pools.“. It would have been more helpful to say that one gigaton of ice is enough to raise global sea-levels by the thickness of a blow-fly’s eyelid.

      • I wonder how much of the water released is them evaporated and rains over land and then never to find it’s way in the ocean again or left in the evaporation cycle. No way it has all been left in the oceans

    • Indeed Stephen W,

      It is well known that the ice amounts at either pole are strongly affected by the ocean currents, and in both cases their variation is over many decades (30-80 years).

    • in the article: ‘sea level rise is being driven by the loss of the floating ice shelves melting in a warming ocean’.
      Comments:
      1. Floating ice cannot make sea levels rise.
      2. Increasing sea levels increases precipitation on land and puts more water on land.
      3. Climate scientists play around with uncertainties and pretend whatever they can think to be a cause of change.
      4. Warm ocean currents periodically cause ice sheets to advance and rereat

  2. “We now have a 16-year span between ICESat and ICESat-2 and can be much more confident that the changes we’re seeing in the ice have to do with the long-term changes in the climate…”

    Noooo.

    Historical records indicate long term fluctuations and 17 years are just a drop in the (rising and dropping) ocean.

    • They have other data showing a century long warming ( of questionable origin ). What he is trying to say is that 16y of change gives a measure of how ice is reacting to the slightly warmer global context.

      They will doubtless be trying to push the implied interpretation that this change is ENTIRELY due to that warming ( rather than continued adjustment to the current interglacial ) and that ALL that warming is due “carbon”.

      Neither of which is proven but they skip the need to prove causation, they have a correlation.

      With the world economy now crashed, the whole argument become irrelevant. Come back in 5 years and see whether anyone is still interested in projecting climate 100 years hence. For now we have REAL problems to deal with.

  3. Greenland 2.4×10^15 ton total (Total ice mass Fettweise et al. 2008)
    Lost per year 200×10^9 ton (OP)
    Loss per year 0.8% (calculated)

    This must be an error,because according to Fettweise et al. 2008 the mass loos over the last 100 years was 0.4%.
    So have they misplaced the decimal separator somewhere?
    If not, it is time to panic 🙂

    • “Loss per year 0.8% (calculated)”

      Loss per year is 0.00008 of total or 0.008% per year.

      • Using the approach which is so popular with alarmists, we need to take the latest scientific result and assume that it is both 100% accurate (no error) and project it into the future linearly. The clear result is that all of the ice on Antarctica will be gone in 12,000 years.

        /sarc

      • Thanks RegGuheert, me idiot!

        The 0.008% per year sounds a lot less scary than all their “Olympic-sized swimming pools”. But, I guess senseless analogies are needed to sell the message.

        • They present it in ways the average reader can relate to and then be frightened of.

          Hence ‘500 billion tonnes’ – which sounds a LOT, ‘300 Manhattan Islands’ and so on. Gosh that sounds scary.

          If they screamed ‘OMG – Antarctica has lost 0.0008% of it’s surface mass balance in the past year!’ – well that just ain’t gonna scare the children, and more importantly, the politicians.

          • CheshireRed wrote, “…well that just ain’t gonna scare the children, and more importantly, the politicians.”

            I often consider politicians to be nothing more than spoiled children stomping their feet verbally.

            Stay safe and healthy, all.
            Bob

        • The Guardian reported this scary statistic recently, but conveniently omitted to give the total mass of the ice-sheet, thus giving its innumerate readers the totally false impression that Greenland was soon to be ice-free.

          • They should report it in how many teapots that would fill. Then they could truly have a tempest in a teapot.

  4. In a new study published in the journal Science on April 30, scientists found the net loss of ice from Antarctica, along with Greenland’s shrinking ice sheet, has been responsible for 0.55 inches (14 millimeters) of sea level rise to the global ocean since 2003.”

    Wouldn’t be surprised if this is used some day in a court to sue the US and/or oil companies.
    Wonder if this ‘science’ study was done in part for this purpose?

  5. ”Ice that melts from ice shelves doesn’t raise sea levels, since it’s already floating – just like an ice cube in a full cup of water doesn’t overflow the glass. But the ice shelves do provide stability for the glaciers and ice sheets behind them.”

    Is this really something new? I bet it’s happened all the time.
    Eamon. (With the aprop. tint of sarc.)

    • Significant amounts of data, numerous research studies, and observations by James Kamis referenced in http://plateclimatology.org, that many of the Arctic’s geological features are in fact very active and emitting massive amounts of HCF (heat transfer and chemically charged temperature altered fluid) released from active geological features into Arctic region oceans, bedrock, and atmosphere (Carmack 2012). Evidence supporting this idea is abundant, reliable, and convincing.
      The major geological features of the Arctic region as shown on Figure 9 in Kamis’ paper are:
      • Greenland / Iceland Mantle Plume
      • Mid-Arctic Rift System
      • Baffin Bay / Labrador Rift System
      • Aleutian Island / Kamchatka Convergent Plate Boundary
      All these geological features are proven emitters of significant amounts of HCF.

    • Eamon Butler:
      No. Beware the assumptions researchers use to drive their conclusions and opinions.

      “But the ice shelves do provide stability for the glaciers and ice sheets behind them.”

      Massive glacier(s) flowing downhill, because of the weight of the ice behind it and gravity, are allegedly blocked by sea ice?
      Not even “grounded” sea ice provides a big enough obstacle to block/slow a glacier.
      Just more irrational assumptions by deluded researchers desperately making excuses.

      • ATheok
        One frequently sees the claim about the buttressing effect of the floating ice. I have yet to see a quantitative defense of the claim.

        Newton’s First Law says that an object in motion (the glacier) tends to maintain its direction and speed unless acted on by some extraneous force. Because of gravity, and friction with the bedrock below, a glacier establishes a speed (ignoring surging events). That speed, along with the mass of the ice, gives the glacier a momentum that comes close to the proverbial “irresistible force. The argument is that the inertia of floating ice is an effective impediment to the momentum of the glacier, of a magnitude similar to the base friction. Consider that, while the forward motion of a glacier is imperceptible to a human observer, it still has a finite, measurable speed. As new, floating pack ice forms at the leading edge of a glacier, it matches the speed of the grounded glacial ice. That is, even as it thickens, the floating ice doesn’t offer any inertial resistance to the continued movement. The inherent inertia only offers resistance to an acceleration! If the pack ice did offer significant resistance to the forward motion of the grounded ice, it would be under compression and one might expect to see compression ridges near the contact. Instead, what is observed are tension cracks, which often become the detachment lines between pack ice and grounded, glacial ice. The tides and waves heave the floating ice around and result in brittle failures.

        I would liken the effective buttressing effect of the floating ice to be similar to the resistance offered by an ice skater trying to slow down a de-railed locomotive careening across the frozen pond they are skating on.

  6. Last century sea level rose 7-8 inches. Don’t think I’ll worry too much about the current rate of about 4 inches per century.

    • Bob Koss
      “Don’t think “I’ll” worry too much about the current rate….”
      “You” are right… “you” wont have to.

      • Well unless my grandchildren are under 90mm high, THEY won’t have to either.

  7. I say BFD to this study. We are living in the Holocene Epoch, an interglacial period of time. Glaciers advance during ice ages and recede during interglacials. Geology 101.

    • Minor correction. Glaciers advance during glacial periods, we’re still in an “ice age”.

  8. Erm… Just by looking at the picture of the whole antarctic, while there are some small scary-looking brown bits around the coasts, and particularly on the West Antarctic peninsular (which if memory serves has a lot of active volcanoes under the ice), the whole of the rest of the place, to go by the legend, has ice accumulating at up to 0.5m per year.

    I suspect we have nothing to worry about.

    • What sort of a scale bar is that? Everything over 0 is blue and then under 0 is in a red-purple spectrum. I struggle to see the difference between -1 and -10m which is probably the way it was designed! That’s a crazy colour scheme. And as Disputin has pointed, out most of the surface area has gained ice and, if I can see a tiny band of white at 0, then that means large areas have seen no change.

      • Liam
        About the only places that the ice loss exceeds 1 meter per year is the west coast, known to have warm geothermal anomalies, and under-ice volcanoes. Neither of which is mentioned in the article. They leave it up to the reader to assume it is all the result of warming water and air. If the ice losses were the result of global warming, then one would reasonably expect to see similar losses around the entire continent, and not primarily, and of greatest magnitude, on the west coast.

  9. 16 years is now ‘long term’, except when the Pause was 17+ years long when it was too short to matter. I see.

  10. Are any corrections made for isostatic and tectonic changes that can affect land surface elevation?

  11. So, 0.55 inches of sea level rise over a 16 year span from melting ice in both Greenland and Antarctica. There are five 16 year spans between now and 2100. So “if present trends continue,” by 2100 those two locations will have contributed to create 2.75″ of sea level rise. No wonder Gates and Obama bought seaside homes.

  12. As everyone has noticed:

    … the net loss of ice from Antarctica, along with Greenland’s shrinking ice sheet, has been responsible for 0.55 inches (14 millimeters) of sea level rise to the global ocean since 2003.

    That’s less than 1 mm per year. The rate of sea level rise just keeps going down. WUWT The alarmists are still pushing their alarmist crap but the data makes them look more and more ridiculous. Folks are going to notice.

  13. Between this morning and this afternoon, temperature increased by 6°C.

    This is a deadly trend :
    – In France, we will not even be able to see the bullshit lockdown exit next week !

    • ICESat2 is good, much better than ICESat1

      Interesting they would compare more precise data against less precise data. !

      With a big gap between

      Also interesting that the big melt areas are above volcanic regions

    • ICESat 1 had MANY technical+performance mishaps. The uncertainties on those measurements are much higher than anticipated, and cut back on the value of those data.

      • Bad data just presents more opportunities to massage the data, until it shows what you want to see.

    • chaamjamal
      You remarked, “… it does not tell us why it melted.” Yes, the implication is that the melting is occurring because of the atmosphere warming from retained heat. However, it has been mentioned in the news lately that the recent ice losses in Greenland are the result of increased insolation because of reduced cloudiness.

  14. “The findings come from ICESat-2, which was launched into orbit in fall 2018 and began taking detailed global elevation measurements, including over Earth’s frozen regions. By comparing the new data with measurements taken by the original ICESat from 2003 to 2009…”

    “We now have a 16-year span between ICESat and ICESat-2”

    I question the validity of the second quote.
    They have data for a six year period, then a gap for nine years, then data for two years.
    The validity of any conclusions drawn must depend on guessing that the missing nine years showed a LINEAR progression from the original measurements to the new measurements. But the progression could have been any damned thing ! Sampling the values near the start and the end of the sixteen years period tells us nothing about the intervening values.

    In the missing nine years the Antarctic could have first experienced a huge loss of ice, which has been re-deposited in the end of the nine years; or conversely it could have experienced a huge gain at first which has melted away towards the end of the nine years. It is unlikely to have been either of these extremes, but without a lot more long-term data there is no justification for rejecting the idea, and claiming a linear progression from which some hypothesis may be drawn.

    Is there no-one is the Main Stream Media prepared to call out this appallingly poor, scientifically-unsupportable claim that a (disjointed) few years data is sufficient to support the claims made for it?

    • Exactly, what the gap provides is the ability to makeup data. We already know that a fudge factor is applied to the data for isostatic rebound. What this all means is the entire result could have been anything the authors wanted it to be. I think we all know what they wanted. It just had to show a loss.

      Now, with this loss being so small it kind of points to the idea that this was as far as they thought they could go and not look like fools. That would indicate the real answer was probably a gain in Antarctica with a small loss in Greenland. The net change is probably close to zero.

    • Not to mention that the original ICE-SAT data was the data used by Zwally et al. 2012 to determine that Antarctica had a net GAIN of ice.

      So what exactly is the error on these estimates piecemealed together with two different sets of satellite data with a 9 year gap, and which the original data set was interpreted from anywhere between -100 to +80 gT/yr?

    • with a 9 year gap between satellites, there is no possibility of calibrating between the two.
      So the idea that both satellites are actually measuring the same thing is just an assumption.
      What we actually have is two independent data sets, any attempt to link them is just hand waving.

  15. It’s a textbook lesson in how to make mountains from molehills. Even the scale at the bottom left makes me laugh. My car has a speedo up to 160mph, it wouldn’t do 160mph if I pushed it out the back of a cargo plane from 15000ft.

  16. Not that it really matters right now’ but as the small lose of ice is in West Antarctica , but that’s where the volcano’s s are.

    So should we really worry about something which may happen in 100 years time or the long term effects of the 19 virus,

    VK5EKK MJE

  17. Why do they need to sully decent data collection work with partisan language.

    “In Antarctica, the dense tracks of ICESat-2 measurements showed that the ice sheet is getting thicker in parts of the continent’s interior, likely as a result of increased snowfall, Smith said. ”

    LIKELY increased snow? What else would it be over such a broad area. Too often the language of uncertainty is applied to signals against the narrative and language of certainty is applied to signals that match the narrative. It’s subtle but enough to subconsciously sway an unsuspecting reader. Like this:

    “But the loss of ice from the continent’s margins, especially in West Antarctica and the Antarctic Peninsula, far outweighs any gains in the interior.”

    FAR outweighs? Antarctic ice sheet is ~26.5 million gigatonnes, and the net loss was 118 gigatonnes, or 0.0004% total. That’s the equivalent of a 250 pound human losing 0.5 grams of body weight. That’s 1/2 ml, you sweat more than after 1 minute of a brisk walk.

    • Yes, and the actual calculation of ice loss was affected by their calculations of water density in the ice pack – how was that determined. A few percentage points one way or the other would change loss to gain. I guess I should review all the methods to see just how certain their finding is and how dependent on these density adjustments.

    • Funny how none of these numbers are ever reported with error margins. As we’re dealing with very small differences between very large numbers, I wouldn’t be surprised if the overall loss is actually smaller than the margin of error.

  18. Forgive my ignorance, which is cavernous in some things. Msmts done by altimeter? How do they know Antarctic itself didn’t rise [or fall]? How would they even detect a 1mm rise of Antarctic? How can they even establish the “sea level” – like the “temperature” of the earth? This stuff is all relative to something. That was “measurable” a few years ago?

    • This is how they are able to get any answer they want. They adjust the data for the land movement. How they adjust the data is extremely important. It can change gains into losses and vice versa. With the numbers this small I think the error bands are probably bigger than the claimed changes, no matter what they tell us.

      • Adjustment is just one step in homogenization. Science works in mysterious (and frequently profitable) ways.

    • John
      It is worse than that, because in the interior of the continent they have to rely on coarse spatial-resolution gravity models to estimate the varying height of the satellite. Hopefully, Kip Hansen will be providing us with a new analysis of these measurement problems. It has been discussed at length in previous comments, but not rolled under one cover as an article.

  19. Geologists have pointed out that over the past 500 million years, the earth has had ice caps at both poles approximately 10% of the time.
    That means we are today experiencing those 10%. As a photographer I can tell you that perspective is mightily helpful.

    Take a glass bowl, fill it with ice cubes and top up right up to the rim with water.
    Sit back with a beverage of your choice and observe what happens to the level in the bowl as the ice cubes melt. Hint: the volume of water in solid state is greater than in liquid state. Same goes for the Arctic, so the effect should be a drop in levels.

    • That’s not quite right, tetris. The experiment that you described would indeed normally result in the water level dropping, but that is not due to ice being 10% less dense than liquid water at 0C as you imply.

      Several things throw off your results. If you start out with water that is warmer than 4C and add only a few ice cubes without vigorously stirring to bring all the liquid to 0C, then there will be a temperature gradient in the liquid. As the water cools it will shrink until it reaches maximum density at 4C. Then it will expand again approaching 0C. Since ambient air temperature and the table will be warmer than 0C, more likely 20-25C, the bowl will be conducting heat into the water creating a temperature gradient in a thin film of water on the inner surface and in a thin film of air on the outer surface. Now if the room is at low relative humidity, water will evaporate from the surface and the rate of evaporation will increase if there is a breeze disturbing the thin film of air at the water interface. Most of these uncontrolled variables will lead to water level falling, at least initially.

      On the other hand, if the water/ice mixture is in a temperature controlled chamber and the ice/water is well mixed so that there is no temperature gradient from the top of the bowl to the bottom, then the ice would not melt and remains at 0C throughout. If a small heat source is then applied, the ice starts to melt. If the air is saturated at 0C, and remains at 0C, there will be no net evaporation. In this controlled experiment, there will be no change in water level at all from the beginning of the experiment until all the ice has melted and water temperature begins to rise.

      As the ice melts and takes up less volume, the melt water from above the surface exactly makes up the difference. (Magic of bouyancy)

      In a non-laboratory scenario, where the ice melts in a bowl where ambient air temperature is 20-25C, the water will warm up from 0C once the ice finishes melting. The whole volume will shrink a bit initially until maximum density is reached at 4C. Then it will expand again as it continues to warm. It will expand until the bowl is full again. Eventually it would overflow from thermal expansion, unless evaporation into unsaturated air exceeds the rate of expansion.

      • Thx for the clarification.
        Two questions: what will happen to the level in the bowl at say 20 degrees C and 50% relative humidity.
        And what will happen in the case of the actual Arctic ice?

  20. Ice caps shrinking = terrifying
    Ice caps growing = even more terrifying
    Ice caps staying the same = vanishingly unlikely.

    I guess you just can’t win.

  21. If you actually look closely at the graphical data, there are areas of the ice shelf that have maximum gain juxtaposed with those with maximum loss. This reminds me of NOAAs average sea surface temperature map that shows a quilt pattern. It suggests interpolation parameters that are set for far too high of resolution compared to the actual resolution of the data.

  22. My “eyeball integration” of the image of Antarctica in the above article, considering the color coding of +/- average ice change rates, says the the net over the indicated 15 (16?) year span is about zero, maybe slightly in favor of the blue color (increasing ice). If the latter, this would be consistent other scientific studies over the last five years or so years that have indicated the total volume of Antarctic ice has been increasing:

    From a research study by a NASA team and published in Journal of Glaciology in October 2015 (sitn.hms.harvard.edu/flash/2016/why-is-antarcticas-ice-sheet-growing-in-a-warming-world/ ), the Antarctic ice sheets gained an average of 112 billion tons of ice each year over the period 1992-2001, and continued gaining an average of 82 billion tons each year over the period 2003-2008. Furthermore, as stated in the linked Harvard article: “The Antarctic has gained about 7,300 square miles of ice each year since the late 1970s . . . There is ice loss still occurring at the periphery of West Antarctica; it’s simply that the ice gains in the other regions are greater in magnitude.”

    According to NASA (nasa.gov/content/goddard/antarctic-sea-ice-reaches-new-record-maximum): “Sea ice surrounding Antarctica reached a new record high extent this year [2014], covering more of the southern oceans than it has since scientists began a long-term satellite record to map sea ice extent in the late 1970s.”

    Unfortunately, the above article did not present a similar color-coded image for Greenland’s average ice change rates over the same time period, but here’s what was reported in 2017:

    “Greenland experts with the Danish Meteorological Institute . . .[estimate] about 544 billion tons more snow fell on the ice sheet between September 2016 and August 2017 than melted away. In an average year (1981-2010), net snow accumulation is closer to 368 billion tons.” ( climate.gov/news-features/understanding-climate/greenland-ice-sheets-2017-weigh-suggests-small-increase-ice-mass)

  23. ” they ran the data through computer programs that accounted for the snow density and other factors, and then calculated the mass of ice lost or gained. ”
    and from this they produced
    “for 0.55 inches (14 millimeters) of sea level rise to the global ocean since 2003.”

    “and other factors” Never seen something written for print that left words out, that would be leaving money on the floor.
    Every one of these people should hang their head in shame:
    Other co-authors are Johan Nilsson and Fernando Paolo at NASA’s Jet Propulsion Laboratory; Brooke Medley, Thorsten Markus and H. Jay Zwally at NASA’s Goddard Space Flight Center; Nicholas Holschuh at Amherst College; Susheel Adusumilli at the University of California, San Diego; Kelly Brunt at the University of Maryland; Bea Csatho at the University of Buffalo; Kaitlin Harbeck at KBR; and Matthew Siegfried at the Colorado School of Mines.
    From AAAS and EurekAlert! are not responsible for the accuracy of news releases
    Thanks Charles for the LOLWT

  24. No mention of range of error or variance of measurement.

    Antarctica ice loss 118 gigatonnes plus or minus how much??? 5 percent???
    Greenland ice loss 200 gigatonnes plus or minus how much????
    Is it a 10 percent error, 20 percent. How as the variance determined.
    In science, if you don’t know the variance, you don’t have quantitative information.
    The news release is not a published paper.
    Is the change from 2003 to 2019 significantly different from zero??
    If so, show the basis for your claim.

    As for sea level rise, you could say the same, what is the error of estimate.
    Is there a trend line? If so, is the slope of the trend line significantly different from Zero.
    Rounding off the value to 1 millimeter per year, that means 21st century sea level will rise 100mm, 4 inches.
    Is 100 millimeters per century significantly different from the 20th century???

  25. Forgive my astonishing ignorance but what is the mechanism for ice loss if the temperature across the entire continent is below zero degrees C year round? The glaciers are moving forward, hence snow build up to drive them down. Even if the world temperature has gone up .1 degree C in the last 16 years, I just don’t see where it could effect the melting cycle.

    Greenland, unlike the Antarctic, has a temperature that can fluctuate above and below freezing and just a little up and down can cause ice loss/gain. Not so Antarctica. Or so I think until I become informed.

    • SMS
      You can have loss by sublimation. However, it generally isn’t of the same magnitude as melting. Most of the melting in Antarctica is probably from geothermal hot spots, and water under floating ice.

  26. Earth’s orbit
    Milankovitch cycles
    Sunspots
    Coronal mass ejections
    Magnetosphere
    Astronomic cycles
    Obliquity/eccentricity/precession
    Coriolis effect
    Thermohaline circulation
    Ocean cycles
    ENSO relationship – El Niño/La Nina

    How many of these apply?

    How many of these

  27. NASA’s 2015 analysis if ICESAT data concluded Antarctic land ice was gaining around 100 gigatons/year since 2000… however, those results were not the droids they were looking for…

    I’m so happy our friends at NASA used their Jedi Mind Tricks and “fixed” their Antarctica PR problem.

    Sarc/off

  28. has been responsible for 0.55 inches (14 millimeters) of sea level rise to the global ocean since 2003.

    OMG! We’re doomed, I say. DOOOOOOOMED…..

  29. It should be no surprise that glaciers are melting and contributing to sea level rise. We know that sea level was 4 to 6 meters higher 125,000 years ago at the peak of the previous warm, interglacial period; a fact that is never mentioned by the glacier panickers. Maybe they’re ignorant. So chances are sea level will rise for a few thousand years more to catch up. Who knows? But the rate is so slow—2 mm to 3.1 mm per year measured by tide gauges and satellites respectively; the latter having an instrument resolution of 33 to 40 mm, go figure…—that humans can easily adapt.

  30. Oh my God!!! Almost a WHOLE ENTIRE MILLIMETER PER YEAR!

    I don’t know about the rest of you, but I’m hitting the panic button now.

    • Ummm …. it’s not a millimetre a year though is it. Meting ice is not the only cause of sea level rise.

      • OMG SIMON! It’s prb’ly a whole friggin’ 2-3 millimeters a year!!!!!!!!! Run for the hills….

        • Except that prior to 16 ya there was none.
          So obviously we have an acceleration going on.
          What will it be 16 y from now, and 32, and 64?
          Not an impact on us perhaps but the IPCC doesn’t say there will be.
          That awaits our decendents.
          Something denizens care not a jot about.

  31. Well, we all know that underneath the west Antarctic ice shelf we have some volcanic activity, don’t we? The shelf is just melting from underneath in that area… The major East Antartica is gaining volume, now as before…

  32. (+emphasis)
    “…
    In Antarctica, sea level rise is being driven by the loss of the floating ice shelves melting in a warming ocean.
    …”

    non-sequitur

    “…
    Ice that melts from ice shelves doesn’t raise sea levels, since it’s already floating – just like an ice cube in a full cup of water doesn’t overflow the glass. But the ice shelves do provide stability for the glaciers and ice sheets behind them.
    …”

    • No.
      Grounded glacier noses support the floating ice.
      They are melting due warmer water.
      That allows inland ice to advance.
      Hence SL rise.

    • F. Ross
      From the article:
      “In West Antarctica, we’re seeing a lot of glaciers thinning very rapidly,” Smith said. “There are ice shelves at the downstream end of those glaciers, floating on water. And those ice shelves are thinning, letting more ice flow out into the ocean as the warmer water erodes the ice.”

      • Both my quotes are directly from the article. As written, they cannot both be correct.

  33. Total BS. The margin of error in the measurement is orders of magnitude greater than any changes.

  34. Earlier this week I found very strong circumstantial evidence of NOAA making up numbers when they had missing data on CO2 levels in Mauna Loa air. I would go to Court on this accusation, so confident it is accurate.
    Drawing a wide bow, I would also say that any organisation that knowingly releases dud numbers is not to be trusted and needs reprimand.
    NOAA cannot claim that they did not know. Part of their job is to set up tests to detect this malpractice. Have they also failed that task, or have they created a new definition of malpractice?
    As for ice gains and losses, the reporting over the years has publicised the losses and downplayed the gains, making it hard to picture the overall balance. This cannot be by accident, more likely by design. The design seems to be to alarm the public, but I suggest that it is a function of politicians, not government science bodies, to decide if, when and how alarm should be spread.
    Science, overall, is being harmed by these ignorant people. Forgive them, Father, if they know not what they do. Geoff S

    • Numbers are always the first thing to be manipulated, from media polls to science & everywhere in-between. Reason? So few are left that can understand what’s going on w/their machinations.

  35. I’m not a scientist, far from it, but I have been researching this climate change/global warming/global cooling (yep, I’ve been around long enough to remember the cooling scare in the70’s) since Gore came out with his propaganda movie, and I have concluded it’s one of the more dangerous issues we face in our economic future, I’m afraid for my kids. When I read a post on WUWT, I always read the comments because most of them are by those that are smarter than I am, way smarter and I continue to learn from them. After all my research, it has become apparent this issue is nothing more than the age old plan to redistribute wealth. It didn’t take much research to come to that conclusion, but I continue to read everything I can about the issue to keep myself informed and to recognize the BS when I see it (like this post re: declining ice). My question is, how do we educate the general public they are being fooled? I believe it’s a real problem because the MSM has such a wide sweeping reach.

  36. I have yet to explore an instrument used in CliSci that doesn’t have multiple engineering and scientific application problems that render the claimed results dubious. The claimed 0.55 inches SLR over 16 year period contradicts so many other studies. Even if we accept 0.55 inches SLR in 16 years, that is ~ 13ppm/yr variation of a natural process. The climate process is probably measured in decades or centuries and will have cycles. Even so, 13ppm/yr should be considered rock-solid stability in the natural world.

    Except for the Western Peninsula, the temperatures rarely exceed 0°C. So no “melting” is happening from global warming. Why is it that NASA force-fits all ice mass loss into “melting”? Ice evaporates. Ice can melt from direct solar radiation. Ice melts when it calves into the sea. Ice mass only increases through snow-fall. Slight variations in precipitation patterns can explain the mass loss. (And maybe some geothermal activity).

    It isn’t even challenging any longer to expose the ridiculous claims of these Cli-Sci studies.

    But I guess the desired effect was achieved. Google search: “NASA’s ICESat-2 mission map 16 years.”

    Google delivers 30 pages of search results, mostly with new articles that summarize the study, of course, with all of the obligatory commentaries from the non-technical “technical writers” who tell us “Climate Change is real, and this is further proof of our Climate Crisis.”

    Mission Accomplished NASA

  37. This is how we use our best and latest technology.

    The ICESat-2 numbers looked “good”, showing calamity thousands of years from now, and so were taken without question. The Argo buoy numbers weren’t going the “right way”, showing no calamity, so they needed adjusting.

  38. The idea that you can even measure these changes is absurd. The use of scare metrics (Olympic swimming pools and nuclear bombs) only amplifies the absurdity.

    Apparently, 1 Olympic swimming pool (SI unit “osp”) of the minimum depth (which of course we must use to make sure the count of pools is maximized) has a volume of 2,500 m^3 = 2.5e-6 km^3. 400,000 osp = 1.04km^3.

    According to WikiP, the total volume of the oceans is 1.3e9 km^3. So 16 years of melting have increased ocean volume by 100 x 1.04 / 1.3e9 = ~1e-7 %. Really? We should worry about this? What is the bigger factor in coastal flooding – wind direction, pumping water out of aquifers, destruction of marshlands, estuary and delta engineering projects, etc. or 0.0000001% increase in the volume of the ocean?

    According to WikiP, the total area of Antarctica and Greenland is 14.2e6 + 2.2e6 = 16.4e6 km^2. So 16 years of melting have decreased to average thickness of ice by 1e6 x 1.04 / 16.4e6 = 0.063mm! Color me skeptical that you can measure a fractal surface to that degree of accuracy (over a 16 year span, from space).

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