Scientific American falls prey to denialist memes

The May issue of Scientific American just landed in my mailbox, and an article in the "News Scan" section entitled "IPCC Errors Prompt a Review on Climate Science Data" caught my attention.

The opening sentence reads:

African crop yields wither, along with the Amazon rain forest; Himalayan glaciers disappear by 2035. These are the erroneous predictions ascribed to the most recent report from the UN IPCC [...] So do the few errors in a report exceeding 3,000 pages merit a revision of IPCC processes?

OK, fair enough - except that only one of the three predictions were actually "erroneous". The IPCC WG2 report said:

In other countries, additional risks that could be exacerbated by climate change include greater erosion, deficiencies in yields from rain-fed agriculture of up to 50% during the 2000-2020 period, and reductions in crop growth period (Agoumi, 2003). [...]However, not all changes in climate and climate variability will be negative, as agriculture and the growing seasons in certain areas (for example, parts of the Ethiopian highlands and parts of southern Africa such as Mozambique), may lengthen under climate change, due to a combination of increased temperature and rainfall changes (Thornton et al., 2006). Mild climate scenarios project further benefits across African croplands for irrigated and, especially, dryland farms.

As RealClimate reported, the only "scandal" here is that grey literature was referenced for the 50% claim. The figure isn't factually incorrect - as far as I know - and there's certainly no policy or rule that prevents the IPCC  (especially Working Group II, which focuses on climate change impacts on society and ecosystems) from using grey literature reports. Of course, that didn't prevent Jonathan Leake - perhaps the most inept (or dishonest) science reporter to still hold a job - over at the Sunday Times from turning this into "Africagate".

The second claimed error concerns the IPCC reporting that the Amazon rainforest could react rapidly to a drying climate:

Up to 40% of the Amazonian forests could react drastically to even a slight reduction in precipitation; this means that the tropical vegetation, hydrology and climate system in South America could change very rapidly to another steady state, not necessarily producing gradual changes between the current and the future situation (Rowell and Moore, 2000).

Again, the alleged scandal here is that the Rowell and Moore reference is gray literature (a WWF report). But is it wrong? No. The WWF report cited a 1999 Nature paper, and the author of that paper has confirmed that the figure is correct. RealClimate, Island of Doubt, and Deltoid discuss this in more detail.

To top it off, the SciAm article goes on to say:

. . . one of the IPCC errors came as a result of information provided directly by the Dutch government about the percentage of the Netherlands that lies below sea level and is therefore vulnerable to flooding from rising seas. The government corrected the percentage in a subsequent statement, from 55 to 26 percent of the country as lying below sea level. [emphasis added]

So let me get this straight: the Dutch government made the mistake, and somehow this is an IPCC error?


It's disappointing that a publication as reputable as Scientific American would uncritically repeat these denialist memes.

Melting glaciers revisited

Guess what made the front page of The Australian today?

United Nations' blunder on glaciers exposed

Looks like I beat them to the punch by a month or so.

What comes first: searching, or researching?

Over on Roger Pielke Sr.'s blog, there was recently a guest contribution by Madhav Khandekar. In reference to the melting of Himalayan glaciers, he alleges that "the IPCC authors misread 2350 as 2035" in the 2007 Working Group II document. His basis for this allegation is that a 1996 UNESCO report entitled "Variations of Snow and Ice in the Past and at Present on a Global and Regional Scale, Technical Documents in Hydrology" by V.M. Kotlyakov contains a reference to the year 2350. Khandekar then assumes - on what basis, I have no idea - that the IPCC transposed these numbers in the Working Group document to get 2035. From here, he goes on to say that "we have a raging debate about impending glacier melt-down because of sloppiness of some IPCC authors"

The sloppiness here is entirely on Khandekar's part. Let's follow the chain of citations, shall we?

Fortunately, Khandekar provides an exact citation for the alleged error: the IPCC Working Group II, p. 493. Turning to that page, within section 10.6 (Case Studies), subsection 2 (The Himalayan Glaciers) we find the 2035 number:

Glaciers in the Himalaya are receding faster than in any other part of the world (see Table 10.9) and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate. Its total area will likely shrink from the present 500,000 to 100,000 km2 by the year 2035 (WWF, 2005).

There are a couple of things to note here. First, that the IPCC report is talking specifically about Himalayan glaciers; and second, that the citation is WWF, 2005 - not Kotlyakov, 1996.

So let's look up the WWF reference, which is:

WWF (WorldWildlife Fund), 2005:An overview of glaciers, glacier retreat, and subsequent impacts in Nepal, India and China.WorldWildlife Fund, Nepal Programme, 79 pp.

Page 29 of that report says:

In 1999, a report by the Working Group on Himalayan Glaciology (WGHG) of the International Commission for Snow and Ice (ICSI) stated: “glaciers in the Himalayas are receding faster than in any other part of the world and, if the present rate continues, the livelihood [sic] of them disappearing by the year 2035 is very high”.

The trail appears to run more-or-less cold here, since I haven't been able to find the ICSI report being referenced (at least online), although it might be this one:
http://www.cryosphericsciences.org/general/Hasnain_ICSI_1999.pdf

The above seems like a likely candidate because the author, Syed Hasnain, was quoted in numerous news stories as having said that Himalayan glaciers were likely to disappear by 2035. Although this date doesn't appear in the report, it seems likely that this is the source of the figure used in the WWF/IPCC report.

I should point out, however, that there does appear to be an error in the IPCC report - namely, the quote referring to ice area shrinking from 500,000 km^2 to 100,000 km^2 by 2035. That area could only be referring to global glacier coverage, but it appears within a section referring specifically to Himalayan glaciers. It seems that this area reference (which does appear in the Kotlyakov paper) is what Khandekar latched onto, and assumed that the date figure must also have been cribbed from the same source.

Postscript: I started this post three days ago, but I have since been beaten to the punch by a few other blogs. Drat!