Personally, I shudder at the notion that we might try to place endangered species within the confines of a spreadsheet. I don't instinctively like headline figures - as presented in this new study as being £50bn a year - suggesting a grand total price tag for saving all species. The reality is that hundreds of local projects and initiatives will be required to protect all the endangered species around the world. Such large sums could be used by some as a convenient device to argue it's far too much to consider attempting. I do think, though, that the process of auditing such costs on a "per species" basis is valid, if only to help those who might otherwise fail to focus on such issues.

More importantly, though, I think to view this simply as "saving species" is wrong-headed. I think it far wiser to talk in terms of protecting habitats rather than the species that reside within them. After all, when we talk about protecting species we are actually talking about protecting habitats. Why don't we just say this?

Can we "afford" it? As has already been said by others, it seems more pertinent to ask can we afford not to? These habitats also support - via that dreadful term "ecosystem services" - the one species that has the power, means and comprehension to decide their fate. Why do I have that image in my head of the man in the silent movie sawing away at the branch in the tree upon which he sits?