As promised in my previous post, I have something to get off my chest about the effect of politicisation in the climate change debate on medieval history. Sounds unlikely, I know, but bear with me. The recent fracas over e-mails leaked from the University of East Anglia's Climate Research Unit has a surprising medieval relevance, which Richard Scott Nokes has brought out at his Unlocked Wordhoard, and I just wanted to add a few pennyworth of annoyance. The keywords here would be"medieval warm period". Now if you Google that, it takes a long time before you get down to results that are actually about the Middle Ages. But it mattered for the Middle Ages and it's immensely aggravating to me to have this phenomenon politicised, minimised, kicked around or diminished because of current political debates.

Why does it matter to me, you ask? Well, as a historian, because as close as I have to an answer about what caused the now-legendary 'feudal transformation', or at least the bundle of slow or not-so-slow changes that we have at times piled under that name, starts with it. Between about 700 and 1200, it seems fairly safe to say, the climate in Western Europe got warmer by, say, one or two degrees. Maybe more, but that's all I need to be able to say that rainfall would have decreased, crop yields would have increased, there would have been fewer famines (and that bit we can check from other records and it has been done and checks out, as far as what records we have can demonstrate something from silence), and more surplus. More surplus means more wealth being accumulated, mostly at the top but not all of it, means more resources available for cultural reproduction and patronage, means the economy will support more people which means demographic growth which in turn means increased land use, more production, therefore even more surplus and so on again round the circle like a generator for the high Middle Ages. Technology doesn't leap at the right point, breaking social structures can really only be an effect of economic growth or so we would imagine at least, and generally I have not yet hit on anything else that explains this. So, the fact that people working on it are largely doing so as part of a different enquiry that is not, per se about the Middle Ages, is vexing, because even if they're right that it occurred—which I believe they are because, as I say, I don't see another explanation for everything else that follows from it—they will not be taken seriously enough, because of the kind of opposition that cause reputable researchers to try and massage data so that the opposition can't use it against them.

(Teaching diagram of the Feudal Transformation by yours truly)

There is, in fact, plausible anecdotal evidence for these changes in that period apart from the Norse in Greenland. One thing that struck me very forcefully was a recent piece in the UK newspaper The Guardian, a photo essay depicting those whose livelihoods have been affected by climatic change (or at least, deforestation, salination or acidification of water, increased water uptake, etc.) One of the less ambiguous ones, in scientific terms at least but not morally, was the current chairman of the Torres vinery, Miguel Torres, in what to me is far frontier Catalonia. They are buying land in the Pyrenees where grapes have not been grown for a long time because the lowlands vineyards are drying up. The wine is pretty good, apparently. And hey: you know when those hills were last used for viticulture? You got it. The charters and records of the eleventh and twelfth centuries reveal vines being sold and given that were at altitudes where in the 1950s, as Ramon d'Abadal reported, it was thought that vines could not be grown. He didn't know what this showed, except that Catalan peasants in the Pyrenees were under serious economic pressure. But now, I think we do know and it's happening again. So this is my medieval angle.

(Vines in el Priorat, Catalonia.)

The other reason that this annoys me however is not historical at all, but just one about rationality. It really gets to me that the argument against action on climate change makes so much of this. The argument being that, if the medieval warm period is 'true' and there really were Vikings farming now ice-bound lands on Greenland (irrespective of what the rest of the world may have been getting weather-wise...) then the military-industrial complex (tm) hasn't necessarily caused the current climate rise and so our lifestyle needn't change hurrah! This is so stupid it makes me want to twist necks, but it is a mainstream idea, as shown by another, rather different UK newspaper, the Daily Express, which a few days after I first drafted this conveniently led with a full-page headline,"100 reasons why global warming is natural", and is now taking a similar line on the current snow in the UK. This, I tell you, gives me unto despair for my people (whoever the goshdarn heck they might be). It is stupid for several big reasons.

1. Firstly, it assumes that plural causes of climate change do not operate simultaneously, which obviously need not be true. If the greenhouse effect is demonstrable, then to claim that that is not part of what is going on with our near-global temperature rise is at the very least questionable, even if other things are also going on. (Of course, the Express claim that the greenhouse effect is unproven. The worrying thing is that this is not a fringe paper, yet, it has more market share than the Times or the Guardian.)

2. Secondly, it's not just climate change that urges a lifestyle change (even though I agree with prominent voices that this is a lot bigger than individual lifestyle habits and that action must be government-led); when we hit peak oil, if that hasn't already happened, it is going to hurt.

3. Thirdly, and much more importantly, it doesn't flaming well matter what's causing the temperature rise, it's still happening. Even if it is not that we have just burnt too much stuff and instead that Mother Sun is getting a little more angry in her middle years, the oceans will still rise, the Nile Delta will still continue to flood and before long there will be nowhere left to grow good coffee, and that's probably the point at which these people will notice. Unless you actually deny that the temperature of the globe is going up, which can be made to look surprisingly rational but is at the very least a minority view worldwide, you still have to admit that things will be bad unless we do something so really, where the Vikings (or the Spanish Marchers) farmed does not matter to you right now.

In short, the medieval warm period makes no political difference to thinking people concerned with climate change. It may tell them something about how the Earth behaves climatically over long periods, which would be great (although if you take a long enough view we're all going to bake or sink anyway), but it certainly doesn't mean we don't need to cut emissions, carbon or otherwise, combat overfarming, deforestation and salination, come up with alternative energy sources good and fast and start in on the synthetic food. It really affects none of these necessities. But it did affect my subject population, or so it seems, really quite a lot. So dammit, you kids, get out of my yard.

(Noted in the last stages of drafting this, an op-ed by one of the UEA professors whose mail was leaked, though he has nothing at all to say about whether they were massaging figures or not, just about the problems science has getting itself heard in policy. Hat tip to Fourcultures. Also, cross-posted to A Corner of Tenth-Century Europe, or it will be soon.)

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For the actual debate about the actual medieval phenomenon you could try: Malcolm K. Hughes & Henry F. Diaz (edd.), The Medieval Warm Period (Dordrecht 1994), repr. from Climatic Change Vol. 26 (1994), nos 2-3, though of course the science has accumulated a lot since then. For the wine stuff, see Ramon d'Abadal i de Vinyals, Catalunya Carolíngia III. Els Comtats de Pallars i Ribagorça, Memòries de la secció històrico-arqueològica 14 & 15 (Barcelona 1955), I p. 50, and now C. Arbués & J. Oliver,"Vinyes que ja no hi són. Per una arqueològia agrària del domini feudal del treball pagès: les vinyes de Sorre, Montardit (el Pallars Sobirà) i Musser (la Cerdanya)" in I. Ollich i Castanyer (ed.), Actes del Congrés Internacional Gerbert d'Orlhac i el seu Temps: Catalunya i Europa a la Fi del 1r Mil·lenni, Vic-Ripoll, 10-13 de Novembre de 1999 (Vic 1999), pp. 321-337. For famines try now P. Benito i Monclús,"Fams atroces a la Catalunya de l'any mil", ibid., pp. 189-206, and more widely, troublesome though it is in some other respects, Jared Diamond, Collapse: how societies choose to fail or survive (London 2005).