The IPCC: Hiding the Decline in the Future Global Population at Risk of Water Shortage

More Insidious than the Himalayan error

Guest post by: Indur M. Goklany

Jonathan Leake and Chris Hastings of the Times of London this weekend spotlighted an IPCC error of Himalayan proportions, namely, that, contrary to the IPCC’s Fourth Assessment Report, the Himalayan glaciers will not have melted away by 2035.   This error, they attributed to a series of blunders, bad quality control and poor scholarship.

I want to spotlight another error in the IPCC report.  This is an error, based not on blunders or poor scholarship but on selective reporting of results, where one side of the story is highlighted but the other side is buried in silence. In other words, it’s a sin of omission, that is, it results, literally, from being economical with the truth. It succeeds in conveying an erroneous impression of the issue — similar to what “hide the decline” did successfully (until Climategate opened and let the sunshine in).

I have written about this previously at WUWT in a post, How the IPCC Portrayed a Net Positive Impact of Climate Change as a Negative, and in a peer reviewed article on global warming and public health. Both pieces show how the IPCC Working Group II’s Summary for Policy Makers (SPM), which deals with the impacts, vulnerability and adaptation to climate change, hid the projected decline in the future global population at risk of water shortage due to climate change.  Not surprisingly, news outlets (e.g., here and here) routinely report that climate change could increase the population at risk of water shortage, despite the fact that studies show exactly the opposite regarding the net global population at risk of water shortage.

First, before getting into any details, let me note that just as the hockey stick was the poster child of the IPCC’s Third Assessment report, the designers of IPCC WGII’s Figure SPM.2 probably hoped that it would be the poster child for the Fourth Assessment Report.  The following are excerpts from the earlier WUWT blog:

“Arguably the most influential graphic from the latest IPCC report is Figure SPM.2 from the IPCC WG 2’s Summary for Policy Makers (on the impacts, vulnerability and adaptation to climate change). This figure, titled “Key impacts as a function of increasing global average temperature change”, also appears as Figure SPM.7 and Figure 3.6 of the IPCC Synthesis Report (available at http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf). Versions also appear as Table 20.8 of the WG 2 report, and Table TS.3 in the WG 2 Technical Summary. Yet other versions are also available from the IPCC WG2’s Graphics Presentations & Speeches, as well as in the WG 2’s ‘official’ Power Point presentations, e.g., the presentation at the UNFCCC in Bonn, May 2007 (available at http://www.ipcc.ch/pdf/presentations/briefing-bonn-2007-05/overview-wg2-report.pdf).

“Notably the SPMs, Technical Summary, Synthesis Report, and the versions made available as presentations are primarily for consumption by policy makers and other intelligent lay persons. As such, they are meant to be jargon-free, easy to understand, and should be designed to shed light rather than to mislead even as they stay faithful to the science.

“Let’s focus on what Figure SPM.2 tells us about the impacts of climate change on water.

“The third statement in the panel devoted to water impacts states, “Hundreds of millions of people exposed to increased water stress.” If one traces from whence this statement came, one is led to Arnell (2004). [Figure SPM.2 misidentifies one of the sources as Table 3.3 of the IPCC WG 2 report. It ought to be Table 3.2. ]

“What is evident is that while this third statement is correct, Figure SPM.2 neglects to inform us that water stress could be reduced for many hundreds of millions more — see Table 10 from the original reference, Arnell (2004). As a result, the net global population at risk of water stress might actually be reduced. And, that is precisely what Table 9 from Arnell (2004) shows. In fact, by the 2080s the net global population at risk declines by up to 2.1 billion people (depending on which scenario one wants to emphasize)!

“And that is how a net positive impact of climate change is portrayed in Figure SPM.2 as a large negative impact. The recipe: provide numbers for the negative impact, but stay silent on the positive impact. That way no untruths are uttered, and only someone who has studied the original studies in depth will know what the true story is. It also reminds us as to why prior to testifying in court one swears to ‘tell the truth, the whole truth and nothing but the truth.’

“Figure SPM.2 fails to tell us the whole truth.

“Hints of the whole truth, however, are buried in the body of the IPCC WG 2 Report …”

The entire piece can be read here.

The problem I have with what the IPCC WG II SPM did with the water impacts is best summarized by this excerpt from the US National Academy of Sciences’ book, On Being a Scientist, that I found on Professor Roger Pielke, Sr.’s website today:

“Researchers who manipulate their data in ways that deceive others, even if the manipulation seems insignificant at the time, are violating both the basic values and widely accepted professional standards of science. Researchers draw conclusions based on their observations of nature. If data are altered to present a case that is stronger than the data warrant, researchers fail to fulfill all three of the obligations described at the beginning of this guide. They mislead their colleagues and potentially impede progress in their field or research. They undermine their own authority and trustworthiness as researchers. And they introduce information into the scientific record that could cause harm to the broader society, as when the dangers of a medical treatment are understated.” [Hat tip to Professor Roger Pielke, Sr.]

As a long time science policy analyst, let me note that such conduct is reprehensible.  Expert comments on the Second Order Draft of the SPM (see Items C and D on page 32 of linked document) had explicitly warned that: “It is disingenuous to report the population ‘new water stressed’ without also noting that as many, if not more, may no longer be water stressed (if Arnell’s analyses are to be trusted).” Despite that, the SPM chose to report the increase but ignored the decline.

This was clearly undertaken consciously, as opposed to being the result of a blunder. It is, therefore, more insidious than the Himalayan error.