Climate Change Committee 3
Oct 9, 2011
Bishop Hill in Climate: WG2, Climate: WG3

A week ago I traced one of the scientific claims underlying the the Climate Change Committee's policy recommendations back to source. This was the claim that there would be 5-8% increase in dry areas in Africa.

The source was a paper by Fischer et al 2005, although the dry-areas claim could actually be traced back further.

However, I'm grateful to a reader for pointing out some interesting things about Fischer et al 2005. While it is clearly the source of the IPCC's doom-laden claim, in fact the paper appears much more rather optimistic about the effects of climate change on agriculture than might be expected. Here is what it has to say about sub-Saharan Africa:

Of particular relevance to regional food security is the case of sub-Saharan Africa, where a growing share of people considered undernourished is located. BLS baseline results indicate a significant reduction in both the absolute number and percentage (compared to world  population) of undernourished people, i.e. at risk of hunger, for all SRES scenarios by 2080,  except for A2, due to significantly larger populations and slower per capita income growth in that scenario.

Globally the authors seem to think that the impact of climate change will be small, again with the exception of the A2 scenario.

Finally, in terms of food security, AEZ–BLS results indicate significant climate change effects would occur only if levels of undernourishment were already high under ‘no climate change’ conditions, e.g. as in SRES A2.

As I said in my earlier piece about Fischer et al, the output of climate models is not robust at a regional level enough to inform policy. But what this shows is that the IPCC is actually doing something worse than placing reliance on unreliable studies. It is pointing to the black spot on an overwhelmingly white sheet and using this as the basis for the claims in its report - this does look rather like cherrypicking.

And of course, the Climate Change Committee then pick up these carefully selected findings and use them to inform UK policy.

 

 

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