First the link to this week’s complete list as HTML and as PDF.
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It seems the years 1998–2012 have been the driest in the Levant for at least 900 a. And according to Cook et al. it is of course all down to man-made global warming. Let’s look at the details. I can’t fault either their data nor their methodology, both are sound and reported in detail. What we see are the last decades being unexceptional around the Mediterranean, with no serious dry spell since about 1960 (the scale doesn’t help to be more precise). The cyclicity even suggests, we’ve had it good for some time now and a new spell of drought is due. So what we have here is a strong regional anomaly. In general, and there are many examples for this, regional climate is more strongly influenced by local vegetation cover and albedo than by world averages. I have taken a look at Syria as the largest country in the area. The obvious culprit is off the hook – Syria’s forests have actually expanded by 30 % since 1990 and a short search did not turn up anything on how much of the massive deforestation since antiquity happened in the last century. Still we do have other data. Syria’s population has exploded from 1.5 M in 1920, 2.5 M in 1938, 6.3 M in 1970 to a massive 21 M in 2010. It is the most densely populated country in the region. There is no way this will not have affected the landscape. This well researched and solid article has already been pounced on by political activists – that’s how I found it – so let’s be careful about sweeping unfounded assumptions here, though I do appreciate how they help to gain funding for valuable studies like this.