(Part of the How to Talk to a Climate Skeptic guide)
Objection: Sea ice at the north pole recovered a whopping 9.4 percent from 2007 to 2008 despite the doom and gloom predictions of the alarmists. Yet another wheel falls off the global warming bandwagon.
It is true that the minimum summer ice extent in the arctic ocean in 2008 was 9.4 percent higher than the minimum in 2007. But calling this a recovery is simply not justifiable, not by a long shot. Firstly, at 4.52 million square kilometers, this measurement is 2.24 million square kilometers below the average minimum observed since 1979, when accurate satellite observations began, so we are nowhere near getting back to normal levels of ice cover (source: NSIDC). Secondly, year to year fluctuations are very large and simply reflect the chaotic nature of weather — the change over a single year does not say anything meaningful about climate trends.
So what is the trend?
There are several things worth noting in this image (courtesy of NSIDC). Not only is 2008 below the average, but it also fell well below the downward trend line — the fourth year in a row to do so. Hardly showing signs of recovery, this year is consistent with an accelerating ice loss. We can also see that an almost 10 percent jump from one year to the next is not unprecedented. The jump up from 1995 to 1996 was even larger, nearly double. The differences between 1989-1990, 1994-1995, 2001-2002, and 2006-2007 all were larger than the difference between 2007 and 2008.
We can also see that 2007 was really an exceptional record-setter and aside from that year, 2008 is lower than any other. This is hardly the “warming is over” news the climate denialist organizations and websites have been proclaiming or at least implying.
That’s what has happened, but what were the “alarmist” expectations? It is true that a small number of media reports quoted people saying there might be another record this year, maybe even total ice loss. (Can anyone show me an actual prediction?) It makes a nice sensational headline, after all, but if you look to climate science you see a predictive failure in precisely the opposite direction. No research papers from scientists in the field have predicted ice loss at the rate it has been happening. Checking the IPCC report from 2007, in the “Summary for Policymakers” (PDF) we find this on page 15:
In some projections, arctic late-summer sea ice disappears almost entirely by the latter part of the 21st century.
This is nowhere near a prediction of total summer ice loss by 2008. In fact, it’s looking more and more like it will be wrong on the conservative side — not the hallmark of an “alarmist”!
In short, 2008′s summer arctic ice extent observation is not a wheel off the GW bandwagon — it is one more nail in the coffin of denialism.
This is just one of dozens of responses to common climate change denial arguments, which can all be found at How to Talk to a Climate Skeptic.