Elephant conservation and ivory markets

In order to protect elephant populations, CITES forbids ivory trade. However, several African governments are unable to enforce the ban and poachers are decimating some local populations. CITES is now considering whether to allow legal, controlled trade, so that ivory supply comes from certain targeted populations, and the reduced demand for illegal ivory leads to less poaching of more vulnerable ones. Wasser and coathors argued against this possibility in Science and, in a rejoinder to Walker and Stiles, they write:

Walker and Stiles next argue that legal trade does not increase illegal trade, and CITES should focus on enforcement instead of targeting legal trade. We disagree. The appeal of the market mechanism for managing wildlife stocks presumes well-functioning institutions with unambiguous ownership of the stocks.

They go on to provide evidence that the countries involved lack well-functioning institutions, but do not further consider the question of ownership. Perhaps we should aim at making ownership of elephant populations less ambiguous.

Up to 90% of all species may go extinct in the next thirty years

The statement in the title is not true. Actually, more than 90% of all species may go extinct in the next thirty years. In fact, any fraction of all species may go extinct at any time.

Any fraction of all species may go extinct at any time.

That would be a true statement. Up to 100% of all species will go extinct in the next thirty years (or in the next five minutes, for that matter) is also a true statement. However, the false statement Up to 90% of all species may go extinct in the next thirty years conveys a more "effective" message. Whoever makes this sort of nonsensical statement is more interested in being "effective" than in being truthful.