Is global warming the only environmental problem we face?

In the overall scheme of things it is probably the one that will have  the least impact on biodiversity. The human impact on the planet is the one that will really matter since we are releasing into the environment extremely stable long lived toxins that have not previously been part of the environment and hence few organisms are able to cope with them.

However, the global warming scenario is one that is now being taken seriously by policy makers, not necessarily because they all believe that it will happen, but because the costs of inaction are too large.