How much biodiversity do we want? It's unfortunate that we even have to ask this question, but until we answer it we're likely to see more and more extinctions, along the lines described by Elizabeth Kolbert. Biodiversity is difficult to measure but, again unfortunately, unless we do, and somehow set quantifiable targets, we shall lose it at a high rate as habitat loss and other mankind-induced environmental changes continue apace. Biodiversity, along with other unquantified but crucial contributions to quality of life is something else that is being be sacrificed by default in pursuit of an ever-higher Gross World Product; our de facto over-arching target.
How would a Social Policy Bond regime address biodiversity? We could target it quite directly, using a combination of proxies such indicator species, and areas (and contiguity) of land and sea set aside for conservation.We could also target for reduction the negative impacts of loss of biodiversity.
Myself, I'm no expert in these matters. But there are experts who, if we were motivated, could be brought into a discussion, culminating in biodiversity goals and priorities in ways that maximize society's well-being per dollar spent.
It's not being done, partly because our policymaking is stuck with a system that doesn't allow governments to set goals unless they also achieve them - something that, when it comes to complex, long-term, goals, requiring adaptive, diverse approaches, they cannot do well.
The Social Policy Bond principle is different. Under a bond regime governments - or any wealthy group of people, corporations, or non-governmental organizations - could set goals as lofty and long-term as a world of maximum biodiversity (however it's defined), and reward the people who achieve these goals. We need now, more than ever, diverse, adapative approaches to challenges such as biodiversity loss or, for that matter, violent political conflict; huge threats, but ones that are largely ignored in pursuit of goals whose only virtue is that they can be measured by accountants.