7 May 2009
The tragedy of climate commons
Imagine a group of 100 fisherman faced with declining stocks and worried about the sustainability of their resource and their livelihoods. One of them works out that the total sustainable catch is about 20% of what everyone is catching now (with some uncertainty of course) but that if current trends of increasing catches (about 2% a year) continue the resource would be depleted in short order. Faced with that prospect, the fishermen gather to decide what to do. The problem is made more complicated because some groups of fishermen are much more efficient than the others. The top 5 catchers, catch 20% of the fish, and the top 20 catch almost 75% of the fish. Meanwhile the least efficient 50 catch only 10% of the fish and barely subsist. Clearly, fairness demands that the top catchers lead the way in moving towards a more sustainable future.
The top 5 do start discussing how to manage the transition. They realise that the continued growth in catches - driven by improved technology and increasing effort - is not sustainable, and make a plan to reduce their catch by 80% over a number of years. But there is opposition - manufacturers of fishing boats, tackle and fish processing plants are worried that this would imply less sales for them in the short term. Strangely, they don't seem worried that a complete collapse of the fishery would mean no sales at all - preferring to think that the science can't possibly be correct and that everything will be fine. These manufacturers set up a number of organisations to advocate against any decreases in catch sizes - with catchy names like the Fisherfolk for Sound Science, and Friends of Fish. They then hire people who own an Excel spreadsheet program do "science" for them - and why not? They live after all in a free society.
After spending much energy and money on trying to undermine the science - with claims that the pond is much deeper than it looks, that the fish are just hiding, that the records of fish catches were contaminated by being done near a supermarket - the continued declining stocks and smaller and smaller fish make it harder and harder to sound convincing. So, in a switch of tactics so fast it would impress Najinsky, the manufacturers lobby suddenly decides to accept all that science and declares that the 'fish are hiding' crowd are just fringe elements. No, they said, we want to help with this transition, but …. we need to be sure that the plans will make sense. So they ask their spreadsheet-wielding "advocacy scientists" to calculate exactly what would happen if the top 5 (and only the top 5) did cut their catches by 80%, but meanwhile everyone else kept increasing their catch at the current (unsustainable rate). Well, the answers were shocking - the total catch would be initially still be 84% of what it is now and would soon catch up with current levels. In fact, the exact same techniques that were used to project the fishery collapse imply that this would only delay the collapse by a few years! and what would be the point of that?
The fact that the other top fishermen are discussing very similar cuts and that the fisherfolk council was trying to coordinate these actions to minimise the problems that might emerge, are of course ignored and the cry goes out that nothing can be done. In reality of course, the correct lesson to draw is that everything must be done.
And the connection to climate? Here.
I'll finish with a quotation attributed to Edmund Burke, one the founders of the original conservative movement:
"Nobody made a greater mistake than he who did nothing because he could do only a little."
See here for a much better picture of what coordinated action could achieve."