Are man’s activities altering the climate? Despite having an environmental science degree and a deep interest in environmental issues, bizarrely enough I have never really got around to forming an opinion on the matter. It is certainly true that the consensus among scientists is that man made climate change is a fact and that we should be taking steps to do something about it. If forced, I would say the chances are that they are right.

 But I am very aware that science is far from infallible, that the scientific consensus can be wrong and that if you really want to be wrong in spectacular fashion a great way to do it is to place too much faith in mathematical models. Anyone who doubts that last statement is welcome to my spare copy of the Club of Rome’s Limits to Growth report. For some reason back in the seventies I bought two, which was very much not in keeping with the spirit of a book predicting widespread depletion of natural resources by the end of the twentieth century.

But whether or not climate change is man made, there is no doubt that climates do indeed change.  The data suggests that the climate has been warming for some time.  The models predict this trend will continue. Personally, I would not be surprised if the trend were to suddenly reverse.  But the overall likelihood is that the world is going to be warmer, possibly a lot warmer, in the near future.

A book that takes a very sombre view of what might happen to a world where the climate has changed significantly is Climate Wars by Gwynne Dyer. The title tells a lot of the story. As the climate changes the chances of it leading to fighting are high.

This opinion is based on numerous interviews with influential people and makes the not particularly surprising assertion that military planners around the world are already considering the kinds of scenarios that might play out if the current trend of global warming does indeed continue. It would be remiss of them if they weren’t. But anyone who has followed the course of the outbreaks of either of the world wars might well be alarmed. There is more than a possibility that those conflicts were to a large extent caused simply by the momentum of the preparations for them.

Dyer is on the pessimistic end of the scale when it comes to projections of how much global warming we can expect.  He asserts that climate is changing faster than the models predict and therefore infers that things are worse than we thought and are likely to continue to do so.  This isn’t strictly logical since if the models are wrong then the predictions are no longer valid and we can’t assume that things will continue to get worse.  But we can’t assume that they won’t either.  So let us have a look at how bad things could be if global warming lives up to the worst of our fears.

It is an irony of physics that the effects of global warming don’t affect the whole globe evenly.  And as it turns out – the closer to the equator you are the more severe the effects are likely to be.  Looking at the map, the advanced countries that caused this mess in the first place and have accumulated the bulk of the benefits are the ones least affected.
This isn’t a universal rule.  Australia for example would be one of the big losers.  It is currently a net food exporter.  In the future it could lose its ability to even feed its own population and would be forced to import food.   Florida is another loser, as is southern Europe.   But for northern Europe and mainland USA, the change in climate could well bring increased harvests.

Asia is the starkest example.   The latitude suitable for growing food crops in Asia would move steadily north.  Currently China has a large population which it feeds from an extensive agricultural area. How would China react if the only way its population could be fed was from land that is currently a sparsely inhabited area of Russia?  Remember that even now, agricultural production is a labour intensive business in China.  It provides employment as well as nutrition.   The natural tendency would be for Chinese farmers to migrate north.  How would the politicians cope with this?  Just in case you have forgotten, both sets of politicians have nuclear weapons at their disposal.

But looking at this from an historic point of view, the situation maybe isn’t as unprecedented as it at first appears.   After all, the movement of people in that part of the world was a big enough problem in the past for the Chinese to invest in a pretty big wall to try and keep things under control.   Looking to the other side of the Eurasian continent we find that the Romans had the wall thing going as well.

As I said earlier, man made climate change is a theory, climate change is a fact and has been going on throughout the planet’s history.  I tried to find out what happened to the climate during the time of the Roman Empire.  To my surprise, it seems this is something about which we know very little.  I will bear this in mind when following the climate change debate.  If we know so little detail about the past it does make me wonder how we can have much confidence that we have really nailed what is going to happen next.

But suppose that climate is more variable in recent history than we have assumed.  Could it be that the big migrations that have often punctuated history have in fact been motivated by climate change?   Think of the Roman walls along the Rhine and Danube as not so much like the Maginot Line and more like the fence along the border between the US and Mexico.  That border is currently a pretty permeable one.  Could it be tightened up enough to hold back more and hungrier migrants?  No doubt it could.  The Americans after all are well equipped and well organised.  They hold all the cards.  If they have the willpower they could seal it off completely.  The Romans probably thought the same.

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