I stumbled upon this in google today. Potosi: Drought Reveals Buried Town
The story has to do with climate control and the IPCC. Most of us are honest enough to realize the IPCC has had their credibility questioned over man made climate change and their attempt to scam the people of this world. So here is the Potosi Village article Drought Reveals Buried Town.
EVER since the Intergovernmental Panel on Climate Change’s 2007 report on the impacts of climate change was discovered to contain a major error – that the Himalayan glaciers will be largely gone by 2035 – there has been a media feeding frenzy to find other mistakes. But it misses the point to focus on individual errors sprinkled through the report’s 1000 or so pages (see “Digging devils from the details”). How solid are its headline findings?
The IPCC presented the second section of its 2007 report in April that year at a news conference in Brussels, Belgium. Its message was clear: climate change is happening now, and its impacts will be increasingly felt as more and more carbon dioxide is pumped into the atmosphere. The panel then forecast key impacts.
In this special investigation, New Scientist takes a closer look at these headline forecasts. Our aim is not to uncover a new scandal buried deep in the report. Rather, we explore how conclusions that the IPCC itself regards as key findings reached the top of the heap, and whether the science behind them stands up to scrutiny.
We focus on three key topics: the impact of climate change on water supplies, food, and biodiversity. The investigation reveals that the IPCC’s broad conclusions were sound. Indeed, the stringent rules of the IPCC means the report sometimes understated the potential impacts of climate change – on biodiversity, for instance.
But our findings suggest there may have been problems with the way its conclusions were presented. It was too easy for some numbers mentioned in passing in academic papers to find their way into public presentations of IPCC reports without sufficiently rigorous assessment. Sections reviewing how different regions around the world would feel the impacts, in particular, may not have been subjected to the same close review as others.
The IPCC has shown rigour and attention to detail in many areas, but laxness elsewhere
One of the most dramatic forecasts of the report was that “20 to 30 per cent of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5 – 2.5 °C” above current levels. This appears in several IPCC summaries and was headlined at the report’s launch in Brussels.
The key source is a Nature paper by 19 authors headed by Chris Thomas, then at the University of Leeds, UK, published in 2004. The pioneering study modelled changes to the “climate envelope” in which species live. It found that such warming would leave 15 to 37 per cent of species “committed to extinction”, doomed as their habitats disappeared (Nature, vol 427, p 145).
Early drafts of the IPCC’s 2007 report include this study in a table of 57 related papers. Problematically, Thomas’s study was the only one to claim global coverage – others focused on specific regions or taxa.
One of the IPCC’s lead authors, Guy Midgley of the South African National Biodiversity Institute in Cape Town, says they wanted a major statement on biodiversity threats but knew the Thomas paper alone was not sufficient evidence. Nonetheless, “to be mute on this would have been a significant disservice to policy-makers”.
So Midgley and his colleagues took the decision to reanalyse the other regional and taxa predictions to harmonise their methodology with Thomas’s. This was complex, but the results broadly matched those of the Thomas paper. So the IPCC authors presented the “20 to 30 per cent” extinction to the final plenary meeting where the report was to be signed off. The resulting interrogation “was the most intimidating thing I have ever faced”, says Midgley.
In the final text, Thomas’s phrase “committed to extinction” was watered down to “at increased risk of extinction”. Midgley says it “is not out of line with the Thomas et al estimate, but is far better supported”.
Did it represent the state of science? The Thomas paper was controversial. Six months after publishing the paper, Nature ran three critical reviews of its methods. None of these are referenced in the IPCC report. Midgley says the IPCC’s strict word-counts prevented a full discussion of the issues – an unfortunate situation for a major finding in a report charged with assessing science.
But when New Scientist contacted the authors of those critiques, none demurred from the IPCC finding. One, John Harte at the University of California, Berkeley, said most of his criticisms suggested that Thomas underestimated extinction rates. Far from the IPCC being guilty of exaggeration, he says, its caution may have led it to underplay the extinction holocaust awaiting the planet’s biodiversity in the coming century.
Such caution is less evident in the process that led to the IPCC’s statement on the impacts of drought in Africa. This was another headline statement at the report’s Brussels presentation. It said that by the 2020s, “between 75 and 250 million people [in Africa] are projected to be exposed to an increase in water stress due to climate change”.
The report attributes the source of this conclusion to a 2004 paper by Nigel Arnell, director of the Walker Institute for Climate System Research at the University of Reading, UK. Arnell’s study, in Global Environmental Change (vol 14, p 31), used six models and 14 scenarios, each describing a possible future with varying changes to the climate and human population, to predict how many people will have access to less water in 21 regions of the world.
The study found that an additional 74 to 239 million Africans would suffer from increased “water stress”, depending on the different climate and population scenarios, with an average of about 152 million. The IPCC rounded this range to “75 to 250 million”.
But its interpretation of Arnell’s paper is questionable. The IPCC report ignores another table showing the number of people in different regions who will have access to more water under climate change. The total across African regions ranges between 11 and 175 million, with an average of 111 million. In Arnell’s paper, the two tables were given equal prominence.
Arnell’s study also warned at length about not taking the quantified projections too literally. The figures do not appear in his conclusion. Instead, it says the numbers can be used to compare the relative effects of different climate and population scenarios. The IPCC report and the publicity at its launch did not reflect Arnell’s caution.
Africa undoubtedly faces testing times over water, but the apparent desire to find a quotable number for drought threats in Africa arguably led the IPCC to an unbalanced conclusion.
Water shortages matter most in poor countries because of their influence on food production. The IPCC’s chapter on food concludes that while crop yields in higher latitudes will probably increase under modest warming, “at lower latitudes, crop productivity is projected to decrease for even small local temperature increases (1 °C to 2 °C)”. It says rice yields will be “unchanged”, but wheat and maize will decline.
These conclusions are based on 69 studies, covering a range of climate scenarios. The report also makes clear that if farmers adapt their methods to a changing climate, they may avoid many of the damaging effects.
This global assessment is thorough. But again, the section of the report that discusses crop forecasts for Africa is problematic. Its summary highlights the finding that “projected reductions in yield in some countries could be as much as 50 per cent by 2020″. This captured public attention and has appeared in speeches by IPCC chairman Rajendra Pachauri. But does the dire conclusion reflect the science?
One newspaper recently revealed this claim’s source to be a commissioned report that had not been peer-reviewed. That in itself is not sufficient grounds to dismiss it. Many commissioned reports have sound findings and this one was written by a known expert, Moroccan Ali Agoumi. IPCC authors insist that citing it was legitimate. The real issue is whether Agoumi’s findings justify the IPCC’s conclusion that some countries in Africa could lose half their food production by 2020. Our enquiries suggest not.
Agoumi’s 11-page report, entitled “Vulnerability of North African Countries to Climatic Changes”, was funded by the US Agency for International Development. It covers only three countries: Morocco, Tunisia and Algeria. It simply asserts, without identifying specific evidence or a peer-reviewed source, that “studies on the future of vital agriculture in the region” have identified a number of risks which are linked to climate change, including “deficient yields from rain-based agriculture of up to 50 per cent during the 2000-2020 period”.
This is thin evidence, and the IPCC treated it carelessly. Agoumi said the projected losses were “linked” to climate change, rather than necessarily caused by it. The IPCC ignored this subtlety. Sometimes the IPCC said the decline in yield might happen due to natural variability in the climate as well as man-made climate change, and sometimes it didn’t. IPCC sources this week admitted to New Scientist that this was an error.
Crucially, the IPCC ignored that Agoumi’s prediction applies only to rain-fed agriculture. In arid North Africa much farming is irrigated rather than rain-fed. So the IPCC’s prediction that some African nations could lose half of their crops is in fact based on a fraction of agriculture in three North African nations. The fact is we still know far too little about how African food production will be affected by climate change.
None of this alters the basic science. The findings of the parallel IPCC report on the physical science of climate change remain largely unchallenged. But some scientists involved say the demand from governments for detailed predictions about the effects of climate change within their own borders has led researchers to make predictions that do not stand up to scrutiny.
The IPCC is now laying the ground for its next report, to be published in 2014. The chair of the section on the impacts of climate change, Chris Field of the Carnegie Institution in Stanford, California, has inherited a tainted chalice. He told New Scientist there were flaws in the 2007 report, but that he is “committed to sufficient checking and cross-checking to ensure a truly error-free product next time”.
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