donderdag 7 juni 2012

Living Planet Report (1): Living Planet Index paints a bleak picture, but be careful with your interpretation

WWF's latest Living Planet Report presents a bleak picture, some hopeful trends, an awfully bad indicator and lots of pious words on sustainable development.

The Living Planet Index

The bleak picture is painted by the overall trends in The Living Planet Index, a weighted average of the abundance (or density, or another indicator of well-being) of a 'basket' of species. You can argue about the weights each species gets, of course, but the overall message is that most of the species they monitor are still in decline.

The hopeful trends are in the North: rich country LPIs are rising. There could be many reasons for this. Unsurprisingly, the LPR claims that the rising trends in the North are only possible because rich countries 'export', as it were, the damaging activities necessary for their consumption to poorer countries. I don't doubt this is one of the drivers, but I can't help thinking that it also matters that as we grow richer, we start caring more for the environment. Whether this means that we should all be poor (little consumption of natural resources) or rich (high preference for conservation) is a very, very old discussion in environmental economics.

The LPR also states that just because things are getting better, that does not mean they are going well. The report rightly points towards the fact that Atlantic cod stocks in some places are only a few percent of what they were mid-nineteenth century. Although cods stocks are improving, they could have been a lot better (i.e., we could have had a lot more bacalau than we're having now). Be careful, however, not to interpret this as that we should strive for pre-industrial levels for all species. After all, this would mean that we should never fish at all. The report does not make this claim explicitly, but such claims are made in other indicators. It is important to keep in mind that biomass levels that give us Maximum Sustainable Yield generally lie at about 20%-50% of what the biomass would have been if we did not fish at all. So if a stock is at 5% of its pre-fishing level it could be at about 10% of its optimal size. Always keep in mind: what do we want? Pre-industrial or even pre-human biomass levels are poor benchmarks for that.

Next post: Oh boy. They're using the Ecological Footprint

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