arctic iceGood news: I got three guys to put up a total of $1000 against the bet in my recent post, “Ice, ice, maybe (not)“:

It is very safe to say the Arctic Sea will be essentially ice free by 2030, and I’d personally bet on 2020 — any takers?

Not-so-good news: The “takers” are not global warming doubters, quite the reverse — they are three well-known and knowledgeable climate bloggers — James Annan, William Connolley, and Brian Schmidt — and James and William are certifiable climate experts.

That said, I think I’m going to win this, as I’ll explain. I estimate the odds at at least 2 to 1 in my favor — no, this isn’t the same kind of 100-to-1 lock the hydrogen bet is — though James, William, and Brian have, unintentionally, given me (slightly) better-than-even odds. Let’s start with the bet:

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At no time between now and the end of the year 2020 will the minimum total Arctic Sea ice extent be less than 10 percent of the 1979-2000 average minimum annual Arctic Sea ice extent, as measured by NSIDC data or any other measurement mutually agreed-upon; provided, however, that if two or more volcanic eruptions with the energy level equal to or greater than the 1991 Mount Pinatubo shall occur between now and the end of 2020, then all bets are voided.

The 10 percent minimum covers me against straggling ice. I also asked for the two-Pinatubo voiding — I didn’t want to lose this bet if warming is temporarily slowed by an unusual series of big volcanoes.

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Why will I win?

Before answering, let me note that Brian blogs he is “betting against over-alarmism.” Annan says, “I think it is unreasonable to claim that all the models and research (which suggests ice-free around mid-century and perhaps later) is badly wrong.” Let’s see why they are probably wrong, like all the models (but not all the research).

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First, my side of the bet does not appear to be a bad one if recent trends merely remain relatively linear. The commenters on William’s blog (crandles and Gareth) do the math if you’re interested.

But if you’ve been reading Gristmill or Climate Progress, or my book, then you know, to paraphrase Dorothy, “I’ve a feeling we’re not in linearity anymore.” That was the point of my posts: Are Scientists Overestimating — or Underestimating — Climate Change (Part I and Part II and Part III). And Arctic ice is probably the most nonlinear thing going.

Indeed, in Part I, I quote from a talk I attended by a top Norwegian expert (PDF of his PPT here): “The recent [Arctic] sea-ice retreat is larger than in any of the (19) IPCC [climate] models.” And that was 2005!

In an American Meteorological Society seminar, Dr. Wieslaw Maslowski of the Oceanography Department at the Naval Postgraduate School reported that models suggest the Arctic lost one third of its ice volume from 1997 to 2002. He then made an alarming forecast (PDF):

If this trend persists for another 10 years — and it has through 2005 — we could be ice free in the summer.

And again, that was in 2006, so he was talking about being ice-free in 2016! And everyone tells me he is no alarmist.

Of course, in 2007, as one of the normally staid National Snow and Ice Data Center experts, Mark Serreze, said in early September, “It’s amazing. It’s simply fallen off a cliff and we’re still losing ice.” Serreze said a couple of years ago he believed the models that predicted an ice-free Arctic in “2100, or 2070 maybe. But now I think that 2030 is a reasonable estimate.”

By late September, the Arctic had lost “an area approximately equal to the size of Alaska and Texas combined” compared to its “long-term average minimum, based on averaging data from 1979 to 2000.” You can hear Serreze’s latest thoughts, along with other equally alarmed experts, at this recent AMS seminar. (Note that in his talk Konrad Steffen points out that the ice/water shift is very nonlinear in the sense that the temperature over thick ice can get very, very cold, but over thin ice or water, it is near freezing — meaning there is the ability to release huge heat, especially in the fall — which is relevant to the figure below).

In an October 1 press release, the NSIDC makes clear that thinning ice creates a kind of feedback of its own:

One factor that contributed to this fall’s extreme decline was that the ice was entering the melt season in an already weakened state. NSIDC Research Scientist Julienne Stroeve said, “The spring of 2007 started out with less ice than normal, as well as thinner ice. Thinner ice takes less energy to melt than thicker ice, so the stage was set for low levels of sea ice this summer.”

The other reason I made this bet is a Science article I blogged on this summer predicting an accelerated warming over the next several years. Their research suggests “at least half of the years after 2009 [are] predicted to exceed the warmest year currently on record“:

They further predict the year 2014 will “be 0.30° ± 0.2°C warmer than the observed value for 2004,” which means there is a 50% chance that the warming from 2004 to 2014 will be 3/8 that of the warming of the previous century!

So yes, I expect to win the bet. And since I can theoretically win $1000 well before 2020, but can’t lose $1000 until 2020, I’m getting a (very) little better-than-even odds.

And in case you were wondering how the rethickening of the ice might be going now in late fall, here’s a stunning plot of the global temperature anomaly as of Tuesday (click to enlarge):


Yes, large parts of the Arctic are 15 to 20°C warmer than normal! (Tip o’ the hat to Gareth.) This is what we expect as larger and larger swaths of the Arctic are ice-free or only thinly covered with ice in the fall.

So are all the models wrong? As the old saying goes, “The best laid schemes of ice and men … “

This post was created for, a project of the Center for American Progress Action Fund.