The melting of the Greenland ice sheet, above, from higher temperatures is among the climate change effects that could prompt sea levels around the world to rise.

Judging from the comments to my previous post, Why won’t W.Va. political leaders educate the public about climate change science? there are a lot of climate change skeptics and deniers among Coal Tattoo’s readership here in the coalfields.

That’s understandable, given the terrible job local media and political leaders do in trying to explain the issue. And of course, lots of those readers seem to get much of their information from Fox News or the Wall Street Journal, hardly reliable sources for scientific information about global warming or coal.

So I thought I would point out a great piece out this week on the blog RealClimate, which is produced by working climate scientists — actual experts in the field we’re talking about.

The piece is headlined, Sealevelgate, and it explains one great example of how reports from the Intergovernmental Panel on Climate Change actually lowball — not overstate, as skeptics would have us believe — many of the scientific findings about global warming and its potential impacts.

The focus in on the findings in the most recent IPCC report that predicted up to 59 cm of sea level rise by the end of this century. The problem? Well, read on:

First, although the temperature scenarios of IPCC project a maximum warming of 6.4 ºC (Table SPM3), the upper limit of sea level rise has been computed for a warming of only 5.2 ºC – which reduced the estimate by about 15 cm. Second, the IPCC chose to compute sea level rise up to the year 2095 rather than 2100 – just to cut off another 5 cm. Worse, the IPCC report shows that over the past 40 years, sea level has in fact risen 50% more than predicted by its models – yet these same models are used uncorrected to predict the future! And finally, the future projections assume that the Antarctic ice sheet gains mass, thus lowering sea level, rather at odds with past ice sheet behaviour.

Some scientists within IPCC warned early that all this could lead to a credibility problem, but the IPCC decided to go ahead anyway.

And what happened?

Nobody cared about this.

I mention this because there is a lesson in it. IPCC would never have published an implausibly high 3 meter upper limit like this, but it did not hesitate with the implausibly low 59 cm. That is because within the IPCC culture, being “alarmist” is bad and being “conservative” (i.e. underestimating the potential severity of things) is good.

Note that this culture is the opposite of “erring on the safe side” (assuming it is better to have overestimated the problem and made the transition to a low-carbon society a little earlier than needed, rather than to have underestimated it and sunk coastal cities and entire island nations). Just to avoid any misunderstandings here: I am squarely against exaggerating climate change to “err on the safe side”. I am deeply convinced that scientists must avoid erring on any side, they must always give the most balanced assessment they are capable of (and that is why I have often spoken up against “alarmist” exaggeration of climate science, see e.g. here and here).

Why do I find this IPCC problem far worse than the Himalaya error? Because it is not a slip-up by a Working Group 2 author who failed to properly follow procedures and cited an unreliable source. Rather, this is the result of intensive deliberations by Working Group 1 climate experts. Unlike the Himalaya mistake, this is one of the central predictions of IPCC, prominently discussed in the Summary for Policy Makers. What went wrong in this case needs to be carefully looked at when considering future improvements to the IPCC process.

And let’s see whether we learn another lesson here, this time about society and the media. Will this evidence for an underestimation of the climate problem by IPCC, presented by an IPCC lead author who studies sea level, be just as widely reported and discussed as, say, faulty claims by a blogger about “Amazongate”?

Think folks in the coalfields will hear much about this from the Charleston Daily Mail, MetroNews or the Bray Cary media empire? Think any of our political leaders will mention it?