Past Evidence Supports Complete Loss of Arctic Sea-ice by 2035

Our title today is shamelessly plagiarised from the “Watts Up With That” blog of our old friend Anthony Watts. However daring to be different we have redacted the initial word “Claim -“.

The WUWT blog post is bylined “Charles Rotter”, and refers to a new paper in the journal Nature Climate Change entitled “Sea-ice-free Arctic during the Last Interglacial supports fast future loss“. Here’s an extract from the abstract:

The Last Interglacial (LIG), a warmer period 130,000–116,000 years before present, is a potential analogue for future climate change. Stronger LIG summertime insolation at high northern latitudes drove Arctic land summer temperatures 4–5 °C higher than in the pre-industrial era. Climate model simulations have previously failed to capture these elevated temperatures, possibly because they were unable to correctly capture LIG sea-ice changes. Here, we show that the latest version of the fully coupled UK Hadley Center climate model (HadGEM3) simulates a more accurate Arctic LIG climate, including elevated temperatures. Improved model physics, including a sophisticated sea-ice melt-pond scheme, result in a complete simulated loss of Arctic sea ice in summer during the LIG, which has yet to be simulated in past generations of models. This ice-free Arctic yields a compelling solution to the long-standing puzzle of what drove LIG Arctic warmth and supports a fast retreat of future Arctic summer sea ice.

There’s no mention of “2035” in there, so let’s look instead at yesterday’s press release from the British Antarctic Survey:

High temperatures in the Arctic during the last interglacial – the warm period around 127,000 years ago – have puzzled scientists for decades.  Now the UK Met Office’s Hadley Centre climate model has enabled an international team of researchers to compare Arctic sea ice conditions during the last interglacial with present day.  Their findings are important for improving predictions of future sea ice change.

During spring and early summer, shallow pools of water form on the surface of Arctic sea-ice.  These ‘melt ponds’ are important for how much sunlight is absorbed by the ice and how much is reflected back into space.  The new Hadley Centre model is the UK’s most advanced physical representation of the Earth’s climate and a critical tool for climate research and incorporates sea-ice and melt ponds.

Using the model to look at Arctic sea ice during the last interglacial, the team concludes that the impact of intense springtime sunshine created many melt ponds, which played a crucial role in sea-ice melt.  A simulation of the future using the same model indicates that the Arctic may become sea ice-free by 2035.

That’s more like it! So too is the accompanying image of some melt ponds:

Melt Ponds, Arctic Chukchi Sea. Image: Julienne Strove, National Snow and Ice Data Center

The comments underneath the WUWT article are of course 99% nonsense. Let’s see if we can do better here, shall we?


16 thoughts on “Past Evidence Supports Complete Loss of Arctic Sea-ice by 2035

  1. The likes of WUWT and GWPF probably spend a lot of time planning how they are going to explain how Arctic sea ice loss has nothing what so ever to do with CO2 and global warming.
    I really do struggle to understand their mindset, are they just a bit dim or are they evil?

  2. Ha! you’ll notice my comments under there… I hope you’ll put in in with the virtuous 1%.

    The new skeptic orthodoxy appears to be ‘it hasn’t got as bad as 2012 since 2012, so that’s OK then’.

    a new level of magical thinking on Watts, which isn’t what it used to be… Philip I think they’ve moved on from explanation to ‘la, la, la…. nothing to see’.

    Still I feel it helps to confront it (and I’m stuck in the house with little to do!)

      1. Back at WUWT for the moment, it’s intriguing that all and sundry keep insisting that Griff should “take the bet”, but when Jim offers them one on a plate he receives only a cold shoulder in return.

  3. Please feel free to continue discussing the denizens at WUWT’s ignorance and/or malignance, but sticking to the learned journal article for now, here are the conclusions:

    Our study has demonstrated that the high-ECS HadGEM3 model yields a much-improved representation of Arctic summers during the warmer Last Interglacial (LIG) climate compared with previous old-generation model simulations. We analysed simulated surface air temperatures and proxy reconstructions of LIG summer temperatures and showed a 95% agreement between the model and observations. Arctic surface temperatures and sea ice are strongly related. By simulating an ice-free summer Arctic, our LIG CMIP6 simulation provides (direct) modelling and (indirect) observational support that the summer Arctic could have been ice free during the LIG. This offers a unique solution to the long-standing puzzle of what occurred to drive the temperatures to rise during LIG Arctic summers.

    The ability of the HadGEM3 model to realistically simulate the very warm LIG Arctic climate provides independent support for predictions of ice-free conditions by summer 2035. This should be of huge concern to Arctic communities and climate scientists.

    This is not of huge concern to the 99% at WUWT obviously, but what of we 1%?

    1. So if I understand this correctly, significantly increased insolation during the LIG was the natural cause of an ice-free Arctic. Are the authors claiming that natural insolation will be that great by 2035? Or just that current melt ponds are irreversible despite lower or average insolation? And what of much more recent periods? Does their model simulate lower ice cover than current during the Minoan or Roman periods? Do they see that as insolation-driven, or from some other natural mechanism? I think the word ‘claim’ may be well deserved here, unless the paper answers all those questions. I’ll see if I can get a copy.

      In the meantime, my vote is for at least 4 Wadhams of sea ice this year, with a chance of 4.5, if current trends continue.

      1. This seems to be the crux of the melt pond argument:

        In contrast to previous simulations, HadGEM3 includes a physically based melt-pond model, which substantially modifies the albedo feedback. Sea ice melts because of the direct absorption of sunlight and transmission of short-wave radiation through ponded and bare ice to the ocean, which in turn warms. Melt ponds forming in summer months thus contribute to melting sea ice as more radiation reaches the ocean. This relationship is implicated in a faster rate of summer sea-ice melt in HadGEM3 in the LIG than in the PI. In July, most of the LIG sea ice is already melted or has a concentration smaller than 50%. By September, all the LIG sea ice is melted.

      2. Are the authors claiming that natural insolation will be that great by 2035? Nope.

        An ice field with fresh snow on top reflects something like 90% of insolation back into space.

        Melt ponds allow something approaching 90% of insolation to be absorbed by the ice and the ocean.

        All that extra heat doesn’t do the ice a lot of good, increasing and prolonging melt..

        The authors are not predicting that the sun is suddenly going to get hotter. Your first sentence is either a reflection of a basic lack of understanding or a schoolboy’s rhetoric trick, to whit start with a falsehood and build up the case from that.

  4. In Feb 2019 the American Geophysical Union issued a press release.

    https://news.agu.org/press-release/ice-free-arctic-summers-could-happen-on-earlier-side-of-predictions/

    The suggestion is that because the Interdecadal Pacific Oscillation (IPO) has moved into its positive stage that will last from 10 to 30 years, an ice-free Arctic in summer could happen as much as 7 years earlier than suggested by the models that do not include this natural variability.

    To put it simply, a double-whammy of warmth from the IPO plus global heating brings the future to our doorstep.

  5. It’s pretty stupid to think that this is proof of global warming. If CO2 is causing this and CO2 is rising nonstop then the lowest ice should be in 2020, 2019, 2018, 2017…. Instead there’s such a noisy signal. There are too many factors and not enough data to say what it actually means.

    1. No, of course it’s not proof, and no, there is no “linear” as you seem to suggest. The climate is just to complex to lend itself to a mathematical exercise. It’s merely one more of a mountain of indicators that tells us the earth is warming due to increasing CO2.

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