Tuesday, February 09, 2010

Spring is coming earlier: Should we worry?

There was a piece in the Guardian today on a study suggesting that spring is coming earlier these days:
The results showed that more than 80% of trends between 1976 and 2005 indicated earlier seasonal events. On average, the study showed the seasonal timing of reproduction and population growth shifted forward by eleven days over the period, and that the change has accelerated recently.
The article goes on to quote various campaigners and academics as suggesting that this finding is quite possibly a sign of man-made global warming and certainly a serious cause for concern.

But I wonder.

How much does a study lasting 30 years tell us about what it is normal over the period that life has existed on this planet?

There is a view implicit in much popular discussion of man-made global warming that until very recently the planet's climate was stable and benign. Only recently, it maintains, has that climate changed to threaten man. I think this view is mistaken and is another manifestation of our tendency to see whatever was around in our youth as natural and right.

Surely the truth is that our climate has always been changing? (This does not preclude the possibility that some of the recent change is the cause of man-made pollution of the atmosphere.)

Further, species have always been adapting more or less successfully to that change. It is odd in a society where Darwin is now the most honoured intellectual figure (far more than, say, Freud or Marx) that we regard the possibility of species struggling to stay in existence as such an aberration from the natural order of things.

None of this offers any reason why we should not try to conserve species that are under threat. But I suspect that spring coming 11 days earlier after 30 years is the natural order of things, not a cause for deep concern.

2 comments:

Simon said...

Jonathan

I don't think I have ever heard a climate scientist or anybody who's view I trusted espouse the theory you mention, although I do agree that some people may assume it is what they meant.

The problem with climate change is not that the climate is getting warmer, as you say that is natural, it is the speed at which it is occurring. Spring occurring 11 days earlier is of course not a problem, systems can function perfectly well whenever spring happens, but spring shifting its position so rapidly is a problem. An 11 day shift in the life time of a single organism (viz you) is not normal, and it is troubling. Of course Darwinian evolution can sort itself out, but only if there are enough generations in between for a new stable equilibrium to be selected, and that may not be happening right now (or at least not with long lived things like mamils and trees, mosquito's and influenza will probably cope just fine thank you very much!)

Jonathan said...

I have never heard a climate scientist espouse that view either. Which is why I said it is "a view implicit in much popular discussion".

It would be interesting to see a study making use of naturalists' observations from earlier centuries (Gilbert White and all that).

That might give us a better idea of how exceptional a change of 11 days is.