Published in Science earlier this month, the target focusses on a defining feature of biodiversity loss – extinction. The authors claim that it is an ambitious yet achievable near-term target.
The proposal can be praised for several reasons. Firstly, it is so simple that any policy-maker or member of the public could understand and remember it. It is also quite a persuasive way to engage people with conservation. Whilst Aichi target 12 aimed to prevent extinctions, if we adopt a target that allows 20 species to go extinct, it communicates the severity of the situation. When I’ve discussed the target with friends, they’ve been surprised that 20 per year would be a “good” scenario, and therefore, maybe this jarring number will motivate public support. What’s more, the target defines an annual outcome, meaning our progress could be kept in check yearly.
The authors who proposed the target (M. Rounsevell et al.) drew several comparisons to the Paris Climate Agreement. They emphasised that having one clear target is an effective way of engaging policy-makers. Instead of having a long list of targets (e.g. 20 different Aichi targets), all policy-makers would be driven and united by working towards the same clear goal. The question to ask though, is this really possible when nature is so complex? The Paris Agreement is defined by limiting global warming to 2°C, but whilst the temperature is a physical constant, can biological species really be treated as units?
The first thought that came to my mind when reading about the target was the absurdity of placing plants, animals, and fungi all in the same category. If 20 charismatic mammal species go extinct in a year, does that mean we’ve been as successful as if 20 obscure fungi went extinct? On paper, they would both indicate that we’ve met the target, but in reality, the impacts would be completely different. I suppose my point is that no species have the same value, in terms of how much humans care about them and in terms of their ecological function. For example, if bees went extinct in the UK we would lose £117 million worth of crop pollination, but if slugs went extinct, I don’t think people would really mind too much.
One reason the authors gave for the suitability of this target was its supposed “measurability”. This perplexed me, as most species extinctions occur without us even knowing. Confidently saying that we’ve only had 20 extinctions annually would require us to rigorously assess the conservation status of every species on the planet, and given that there are 17,154 species listed as “data deficient” on the IUCN red list of threatened species, this seems an impossible task. As far as I'm aware, any of these 17,154 species could easily go extinct, or even be extinct already, without scientists noticing.
It certainly will be interesting to see if the Convention on Biological Diversity adopts some sort of target like this and, whether it really could catalyse biodiversity preservation. In any light, if it draws attention to conservation, especially from policymakers, then it could be an invaluable tool in the coming years.