It’s All About Fresh Water — Rapid Sea Level Rise Points To Massive Glacial Melt in Antarctica

It’s all about fresh water. In this case, massive freshwater outflows from the vast glaciers covering Antarctica.

This week, a new scientific report published in the Journal Nature found that from 1992 through 2012 freshwater outflow from Antarctica’s massive glaciers exceeded 400 gigatons each year. An immense flood of cold, fresh water. One that helped push sea levels rapidly higher around the Antarctic continent.

But with glacial melt on the rise and with mountains of ice now inexorably sliding seaward, these freshwater flows may just be the start of even more powerful outbursts to come. And such prospective future events have far-ranging implications for sea level rise, global weather, sea ice, human-caused climate change, and world ocean health.

Flood of Fresh Water Drives More Sea Level Rise Than Expected

The researchers discovered the tell-tale signature of this vast freshwater flood through chemical analysis of the seas surrounding Antarctica. The analysis pointed to a broad and expanding fresh water layer over-riding a warmer, saltier current issuing in from the Southern Ocean.

Since fresh water is less dense than salt water, the freshwater layer expands at the ocean surface causing sea levels to rise more rapidly. Meanwhile, the heating of the deep ocean surrounding Antarctica is thought to result in additional thermal expansion of the water column.

The researchers note:

On the basis of the model simulations, we conclude that this sea-level rise is almost entirely related to steric adjustment [changes that effect atomic spacing], rather than changes in local ocean mass, with a halosteric [salt based] rise in the upper ocean and thermosteric [heat based] contributions at depth. We estimate that an excess freshwater input of 430 ± 230 Gt yr−1 is required to explain the observed sea-level rise. We conclude that accelerating discharge from the Antarctic Ice Sheet has had a pronounced and widespread impact on the adjacent subpolar seas over the past two decades.

Antarctic Sea level Trend

(Rate of sea level rise in the seas surrounding Antarctica since 1992. Aggregate sea level rise is indicated in black. Individual seas data is broken out by color. Image source: Nature.)

Previously, increased rates of sea level rise surrounding Antarctica were thought to have been set off by increasing winds around the continent. The winds were thought to push more water up against the ice faces forming a kind of perpetual, low-grade storm surge. But the current finding provides strong evidence that the source of the sea level rise is due to less dense fresh water over-topping saltier waters flowing in from the Southern Ocean combined with increasing heat along the Antarctic sea bed. And, notably, this is not the first study to find increasing freshwater flows spilling into the Southern Ocean. Last year, a KNMI expedition uncovered similar results.

More Evidence of Large-Scale Melt

The study comes on the back of other recent findings showing that warm water invasion at Antarctic glacier bases had led to more rapid than expected melt and destabilization. In May, two NASA studies showed that a broad section of West Antarctica had destabilized and was sliding at an ever more rapid pace toward the ocean (see reports here and here). These findings held stark implications for global sea level rise as large ice regions of Greenland and West Antarctica, containing enough water to raise seas at least 15 feet, are likely already in a state of irreversible collapse.


Regional Anomaly Sea level Antarctic

(Sea level rise anomaly of the region surrounding Antarctica compared with the rest of the Southern Ocean. Red indicates faster than normal sea level rise. Blue indicates slower than normal sea level rise. Image source: Nature.)

This intensifying glacial melt and associated freshwater cap expanding out from the pole has implications — not just for sea level rise, but for sea ice, weather, and world ocean system health.

Impacts For Sea Ice

Large outflows of glacial fresh water may well be involved in the recent observed expansion of sea ice in the zone surrounding Antarctica (see recent related study). Fresh water serves as an insulative cap on the ocean surface preventing warm water from entering the top layer from below. The warm, salty water, in the Antarctic instead pools near the bottom or at the base of the great ice sheets.

Fresh water also freezes at a higher temperature than salt water. So sea ice in an expanding freshwater zone around Antarctica would have naturally higher resiliency even to the rising temperatures now occurring due to human-caused warming. Eventually, however, human heat forcing would overwhelm the ice, but not before a period of related, localized negative feedbacks.

The Iceberg Cooling Effect

The fresh water is a haven for sunlight-reflecting sea ice. It is interspersed with ice bergs from the glacial discharge and the large ice bergs cool the surrounding air. The fresh water layer prevents warm water upwelling from the warm, deep waters surrounding Antarctica. And the leading edge of the fresh water would drive salt-water down-welling along its advancing front. This would push warmer waters toward the ocean bottom, resulting in a kind of heat sink. And this is exactly the kind of dynamic that appears to be ongoing in the Southern Ocean now. These combined impacts are what is known as the ice berg cooling effect associated with large-scale glacial outbursts known as Heinrich Events. And we may well be in the process of setting off one of these geological scale nightmares.


(Iceberg cooling effect under a mid-range warming scenario when global climate models were set to include the effects of large freshwater outflows from polar glaciers at a fast enough rate to raise seas by 60 cm through 2060 and 144 cm through 2080 [left frames]. Note the cooler zones in the Southern Ocean and North Atlantic adjacent to Greenland. Right frames include mid range emissions/warming scenarios and IPCC projected rates of sea level rise. It is worth noting that the amplifying effects of potential additional ghg release from the global climate system, particularly from Arctic and world ocean carbon stores, are not included in these simulations. Image source: Hansen and Sato.)

For global weather, such events have major implications. Regional cooling in the zone of freshwater outflow would juxtapose regional warming in the southern hemisphere meridional zones. This temperature differential would increase with the strength of the fresh water outflow and the rising intensity of the human-driven warming. The result would be a powerfully intensified storm track. Both the intensified storm track and increased atmospheric moisture loading due to human warming would result in much more powerful weather events than we are currently used to and the potential for catastrophic storms would drastically increase.

Amplifying Feedbacks and a Blow to World Ocean Health

Lastly, the expanding flood of fresh water would result in an increasing stratification of the world ocean system. This stratification would drive warm, salty water toward the ocean bottom and deplete already low oxygen reserves in that region. In addition, the extra heat is more likely to destabilize deep-sea clathrates — releasing methane which will speed in the oxygen depletion of the abyssal waters even as it tips the world ocean system to stop storing carbon and to begin releasing it. A combined feedback that is both an ocean killer and an amplifier to the already extraordinarily powerful human heat forcing mechanism.


Rapid Sea Level Rise Along Antarctic Margins Due to Increasing Glacial Discharge

Important Role For Ocean Warming and Enhanced Ice Shelf Melt in Sea Ice Expansion

Update on Greenland Ice Sheet Mass Loss: Exponential?

Grim News From NASA: West Antarctica’s Entire Flank is Collapsing

Nature: Human-Destabilized Antarctica Capable of Glacial Outbursts Contributing to Up to 14 Feet of Sea Level Rise Per Century


Leave a comment


  1. bassman

     /  September 3, 2014

    Haven’t had time to read this but it seems important. It’s not behind a pay wall!

    GISS’s Kelley & Romanou are co-authors of “Ocean’s role in transient response of climate to abrupt GH gas forcing”.

  2. Excellent post, thank you. I especially appreciate the direct links to sources in the body of the text.

  3. uknowispeaksense

     /  September 4, 2014

    Reblogged this on uknowispeaksense.

  4. utoutback

     /  September 4, 2014

    Meanwhile in an article over at Climate Progress
    GOP climate criminals (Darrell Issa & David Vitter) are investigating the EPA over new carbon rules to cut greenhouse gas emissions. Is it ignorance or a death wish?
    What did I read recently “They aren’t stupid, but they’re learning to fake it.” Actually, they are avaricious and stupid too.
    Meanwhile the world burns.

    • What I find stupid is the active action against any solution to an emerging climate crisis and a finite resource crisis that is, sooner or later inevitable so long as you continue to rely on fossil fuels. It is as if republicans beg for a collapse and want that collapse to be as hard as possible.

  5. Loni

     /  September 4, 2014

    Of course this depends on the slope of the ground, but assuming that the ground slopes towards the sea, I imagine at some point we may see very large sections of ice breaking away and slide into the Amundsen Sea?
    Good article, thank you.

    • Loni – If only.

      It may be slightly counter-intuitive, but the problem is the opposite. The sea bed deepens into West Antartica. This means that the further the ice retreats, the thicker it has to be to keep contact with the sea bed; but the thicker ice is in fact more prone to gravitational stress, making it thin and un-ground. And you get more ice-ocean contact, which means more melting as well.

      The danger of gravitational instability is that it can break up ice caps much, much faster than melting alone, it allows ice to be transported away by sea to melt. This can’t happen as fast for ice caps on land.

      • Exactly. The ice is a kind of dam that keeps the water from flooding inland. This makes the ice more vulnerable to destabilization as it melts.

  6. Loni

     /  September 4, 2014

    Thank you Andrew. Is what we are discussing the same thing as what Robert referred to as the Heinrich Events?

  7. And yet, regardless of all the evidence, the facts, the scientific opinion,,,, some people still deny what lays ahead.

    How can we convince our decision makers (politicians) to take effective action and try to turn climate change around before it’s too late.

    So frustrating. Where do these people live ??

    Maybe this cartoon gives a small clue . . . .


    • My small grassroots group is learning from talking to political scientists that you have to work on building relationships with your city council, your state reps, your local congressman or woman (if yours is not as bullheaded and entrenched as mine!). You support and collaborate with state- and nation-wide climate action groups. You write LTEs and OpEds, you table and educate and petition and march. You can bring Bob Inglis to your town to talk to Republicans because he’s a die-hard conservative who lost his seat because he understands climate change and promoted a carbon tax. He now runs the Energy and Enterprise Initiative out of George Mason Univ and promotes fee and dividend. Our telling just the facts just doesn’t work–you have to have a policy in mind that makes sense to the deniers and politicians and you have to build alliances and hope some more heroes like Inglis appear. It takes commitment and hard, thankless work–just like the research and writing Robert and the rest of you do.

  8. Gerald Spezio

     /  September 4, 2014

    Not much time left.

  9. JoeT

     /  September 4, 2014

    I wanted to point to recent news that talk of the coming El Nino is picking up again. As I was saying a few posts back — the 30 day averaged southern oscillation index is hovering around -10 these days. This just came out in Nature. One feature I find interesting is that computer models predicted the stalling of El Nino in the summer and its resurrection in the fall/winter.

    The first signs of an El Niño came in January, when the east-to-west trade winds that blow across the tropics suddenly weakened, and a burst of winds from the west triggered a slow surge of warm water into the eastern equatorial Pacific. In 1997, similar conditions helped to set in motion one of the strongest El Niño events on record, which caused extreme rainfall along the western coasts of North and South America and drought in Australia and southeast Asia, resulting in thousands of deaths and tens of billions of dollars’ worth of damage.

    Sustaining an El Niño requires the ocean and the atmosphere to work together. Normally, the warming in the eastern Pacific that presages such an event strengthens wind patterns that push even more warm water eastward. But this year, the atmosphere did not play its part. As a result, the ocean cooled in May, June and July, and the El Niño stalled.
    Related stories

    Anthony Barnston, a seasonal climate forecaster at Columbia University in New York City, says the latest data show that winds from the west are again forming — a second chance for a full-blown El Niño. His team estimates that there is a 75% chance that a weak to moderate event will form by the end of this year, just a bit later than researchers had thought. The predictions are in line with those from the US National Oceanic and Atmospheric Administration (NOAA), which puts the chance of a weak to moderate El Niño at 65%.

    Climate central also has a similar article:

    • Great article and thanks for the link!

      These are the values I have for the last 33 days:

      2014 215 1012.91 1014.20 -17.66
      2014 216 1012.86 1015.65 -26.77
      2014 217 1013.76 1016.35 -25.55
      2014 218 1014.38 1015.75 -18.15
      2014 219 1014.90 1014.90 -9.83
      2014 220 1015.61 1014.45 -2.79
      2014 221 1015.70 1014.80 -4.37
      2014 222 1015.48 1015.25 -8.44
      2014 223 1014.74 1014.60 -8.98
      2014 224 1014.43 1014.20 -8.44
      2014 225 1014.66 1014.35 -7.95
      2014 226 1015.39 1016.05 -13.84
      2014 227 1015.80 1016.60 -14.69
      2014 228 1015.65 1015.10 -6.49
      2014 229 1015.70 1014.35 -1.64
      2014 230 1015.51 1015.10 -7.34
      2014 231 1015.31 1015.50 -10.99
      2014 232 1014.36 1014.85 -12.81
      2014 233 1014.26 1014.15 -9.17
      2014 234 1014.36 1014.55 -10.99
      2014 235 1013.86 1014.30 -12.50
      2014 236 1013.91 1014.20 -11.59
      2014 237 1014.53 1014.00 -6.62
      2014 238 1014.04 1013.80 -8.38
      2014 239 1013.54 1013.20 -7.77
      2014 240 1013.86 1013.15 -5.52
      2014 241 1013.41 1013.70 -11.59
      2014 242 1011.33 1014.00 -26.04
      2014 243 1012.45 1013.05 -13.47
      2014 244 1014.51 1013.00 -4.81
      2014 245 1014.86 1013.30 -4.51
      2014 246 1014.23 1014.25 -13.90
      2014 247 1014.45 1013.25 -6.65

      Average is about -10, as the article notes. Usually,sustained values below -8 are coincident with El Nino.

      A moderate El Nino could well help the US West Coast. Weak might not be enough.

  10. Greg Smith

     /  September 4, 2014

    Side Note: Tesla appears to be announcing its new battery factory for Nevada 7 pm EST. If correct, the location is near Reno. It appears to be smack in the middle of the exceptional drought map area that extends outward from California into Nevada. Irony? How do you build the future in such a place? The story is intriguing because it is the future constructed in the middle of a place where now we see the impacts of climate change by a visionary who is trying to mitigate those impacts. The electricity for this gigafactory is envisioned to be alternative and renewable and local but where will the water come from for this factory and all its direct and indirect support structures?

  11. Cartoonmick – love the flat earth cartoon – it’s now illustrating the Rogues’ Gallery section at the Apocalypsi Library at the End of the World,

  12. Jay M

     /  September 4, 2014

    So, it seems like a Heinrich event would get a lot of people’s attention? Could an abrupt sea level rise that was truly damaging to near sea level inhabitants occur over a matter of a few months?

    • Geologically, large glacial outbursts have occurred in the form of pulses or spikes in the background melt. It appears that sections of ice catastrophically fail due to internal ice sheet stresses brought about by warming. If we have a large glacial outburst event, the change in sea level would certainly be noticeable short-term. However, we would likely have some warning for such an event as the ice sheets would show severe deformation, the surface of the ice would be riddled with very large melt lakes, or an ice dam would form with a large water source behind the ice or locked within submerged lakes within the ice itself.

      Of course, it’s possible we could miss some of the signs as we don’t exactly know what to look for.

      • Mark from New England

         /  September 4, 2014

        Or, Senate and House Republicans could defund the satellites that would give us such a warning😦

    • Mark from New England

       /  September 4, 2014

      Over a few months? Don’t know … Robert?

      • A single large outburst event could happen rapidly. We have measures that show 14 feet of sea level rise at the end of the last ice age occurring over the course of one century during which several large and sudden outburst events took place.

        I guess it depends on what you see as enough to get people’s attention.😉

        But what we see in the geological record are trees from Alaska that were ripped from the soil in one such event, carried across the Pacific Ocean and embedded in the cliffs of islands off the Russian coast many hundreds of miles away and more than 500 feet above the then sea level. The size of the tsunami-like outburst must have been gargantuan to fling water and trees so far and so high.

        This happened due to a massive glacial outburst flood issuing from the Laurentide Ice Sheet.

        Given that the current pace of human forcing is six times faster than at any time in the geological record and that we are currently warming 25 times faster than at the end of the last ice age and could warm 100 times faster this century, then, yes, we might consider such events that get the attention of people on the coastline are certainly possible.

        Is it not something that I’ve added to my broad assessment. Not at this time. But it is something that I worry about. Just as I worry about methane release on a larger than expected scale. If we continue BAU emission, we would almost certainly see some horrific events. A 1 meter sea level rise would be bad. A 3 meter sea level rise would be terrible. Anything worse would be tough to imagine once you consider the movements of mountains of ice that are involved.

        You push nature too much and the violence can be unimaginably extraordinary.

        • And yet the violence of nature is extraordinary only on human scales and by human standards. It’s just a little ripple in the ocean by planetary standards – larger than the normal ones, but not so big …

  13. – Here’s some “positive talk-back” that we need to hear more of:

    Nobel Prize Winner Says Climate Skeptic Perspective Should Be ‘Crushed and Buried’

    A British Nobel Prize winner and the head of major scientific societies recently said “serial offenders” casting man-made climate change in a skeptical light “should be crushed and buried.”
    The Guardian reported that Sir Paul Nurse, the incoming president of the British Science Association and current president of the Royal Society, made these remarks to journalists ahead of the British Science Festival. He encouraged scientists to call out politicians and others who skew scientific data.

    • Ps A relevant abstract:
      Climate Risk Management
      Volume 3, 2014, Pages 1–12
      A probabilistic analysis of human influence on recent record global mean temperature changes
      December 2013 was the 346th consecutive month where global land and ocean average surface temperature exceeded the 20th century monthly average, with February 1985 the last time mean temperature fell below this value. Even given these and other extraordinary statistics, public acceptance of human induced climate change and confidence in the supporting science has declined since 2007. The degree of uncertainty as to whether observed climate changes are due to human activity or are part of natural systems fluctuations remains a major stumbling block to effective adaptation action and risk management…
      Thanks Robert, for the up to date posts.

    • I couldn’t agree more. I crush and bury them all the time here. Added a few renewable energy skeptics to the butcher block as well.

    • Phil

       /  September 4, 2014

      Check out the comments to the ‘Nobel Prize Winner’ article – climate change denier central.

  14. SOEE
    – And today from Arctic News:
    State Of Extreme Emergency by Malcolm Light

  15. Spike

     /  September 4, 2014

    Bloody hell I’d not seen that North Atlantic cooling by 2080 as so extensive before. Looks like the UK and Northern Europe have a shedload of storms heading our way under BAU. Ladt winter may have been just an appetiser.

  16. Special Report on Sea Level Rise from Reuters:

    “For this article, Reuters analyzed millions of data entries and spent months reporting from affected communities to show that, while government at all levels remains largely unable or unwilling to address the issue, coastal flooding on much of the densely populated Eastern Seaboard has surged in recent years as sea levels have risen.”

    • Good for Reuters.
      Ii also has an example of the denial and skepticism that public officials get away with. It’s something that needs to be countered somehow.

      This, from the island town of Chincoteague, Virginia, where — ‘The beach has been disappearing at an average rate of 10 to 22 feet (3 to 7 meters) a year…
      Like many local residents, Wanda Thornton, the town’s representative on the Accomack County board of supervisors, accepts that the sea is rising, but is skeptical that climate change and its effects have anything to do with the erosion of the beach. As a result, “I’m just not convinced that it requires the drastic change that some people think it does,” she said.’

      She accepts the drastic loss of 3 to 7 meters of the town’s beach, but somehow, just not convinced.
      The mind boggles… boggle, boggle…

      • Ps ‘In January 2009, a federal interagency assessment of the mid-Atlantic coast said that both Wallops and nearby Assateague islands may have crossed a “geomorphic threshold” from a relatively stable state into a highly unstable condition – one in which rising seas could trigger “significant and irreversible changes.” The islands could shrink, move or break apart.’

        … “geomorphic threshold”, that’s a good term to keep in mind.

      • The Chesapeake bay estuary sees massive losses to lands ongoing. We’re losing whole islands at the moment.

    • Excellent report, David. Thanks for this!

  17. Colorado Bob

     /  September 5, 2014

    Research resolves discrepancy in Greenland temperatures during end of last ice age

    In addition to the gradual warming of five degrees (C) over a 6,000-year period beginning 18,000 years ago the study investigated two periods of abrupt warming and one period of abrupt cooling documented in the new ice cores. The researchers say their leading hypothesis is that all three episodes are tied to changes in the Atlantic meridional overturning circulation (AMOC), which brings warm water from the tropics into the high northern latitudes.

    Read more at:

      • Colorado Bob

         /  September 5, 2014

        Past temperature in Greenland adjusted
        September 4, 2014
        University of Copenhagen – Niels Bohr Institute
        One of the common perceptions about the climate is that the amount of carbon dioxide in the atmosphere, solar radiation and temperature follow each other. This correlation is also seen in the Greenland ice cores. But during a period of several thousand years up until the last ice age ended approximately 12,000 years ago, this pattern did not fit and this was a mystery to researchers. Now researchers have solved this mystery using new analytical techniques.

  18. Colorado Bob

     /  September 5, 2014

    Are reinsurers really underestimating their exposure to extreme weather by 50%?

    WASHINGTON—Standard & Poor’s Ratings Services says in a new paper that reinsurers are taking a “huge risk” by ruling out the potential that climate change is already impacting their exposure to catastrophic losses.

    Indeed, reinsurers might be underestimating their exposure to extreme weather by an average of about 50%, the paper says.


  19. Colorado Bob

     /  September 5, 2014

    Death of Yoda the 650-Year-Old Tree Tells Tale of Southwest Drought

    A Douglas fir affectionately named Yoda survived many a drought in its six-plus centuries of existence in a rugged lava flow in the El Malpais National Monument area near Grants, New Mexico, but it couldn’t weather the current extreme drought in the parched Southwest.

    The recent death of the 7-foot-tall tree, estimated to be more than 650 years old, is a testament to the severity of today’s drought, scientists say.

    A core sample obtained in 1991 established that Yoda had lived at least since 1406, but it likely had been alive since 1350 or so, Henri Grissino-Mayer of the University of Tennessee, Knoxville, told NBC News. Yoda had survived a “megadrought” in the 16th century — an intense period of dry weather that plagued Mexico and North America for decades and caused major tree losses.

    Today, Grissino-Mayer said, “We’re seeing massive mortality in tree populations that is unprecedented.”


  20. Colorado Bob

     /  September 5, 2014

    Study Finds Evidence of Multicentury Drought
    Findings Show 3,000-Year Precipitation Record for SoCal, Tie to El Niño

    The study also compared the 3,000-year-old history of winter rainfall and dry periods with El Niño conditions, which confirmed a “clear connection” between El Niño and precipitation in Southern California. The findings also are the first to show that this relationship is robust for the region in the period before measured records, which document only the last 100 years or so, Kirby explained.

    “It’s exciting because we’re providing a glimpse on how precipitation has changed, but more importantly, why it’s changed,” he said. “It demonstrates that the amount of rain in Southern California is predominantly responding to conditions in the tropical Pacific Ocean.”


  21. Kevin Jones

     /  September 6, 2014

    Since I first saw the image(s) you posted from Hansen and Sato a year or so ago they have left me stunned. The one on the lower left of 2080 with ice melt, I mean. I wrote Hansen, “How could this not be plausible?” It was then that it sunk in: the title of the book, chapter and sub-chapter: Storms of My Grandchildren. The North Atlantic will be No Sea for Old Mariners!

    • No. I think there’s a reason why ships are getting bigger. The power driving storm waves keeps getting more intense. So we have a proliferation of very large waves. Of course, what we see now is noting compared to what we will see if these models are correct.

  22. Kevin Jones

     /  September 6, 2014

    Personally I’d prefer a well-corked bottle to something more titanic…

  23. Greg Smith

     /  September 9, 2014

    Southwest flooding today:
    “Meteorologist Nick Wiltgen: “More troubling were the storms northeast of the city; one gauge reported 2 inches of rain in 30 minutes north of Moapa. This is an extreme amount of rain for a desert environment. NOAA estimates this type of rainfall should happen once every 500 to 1,000 years in that area, ASSUMING NO CLIMATE CHANGE (emphasis added)”

  1. New Study Finds 3-4 Meter Sea Level Rise From Antarctica May be Imminent | robertscribbler

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