Price and value
What does a headline figure like that mean in a useful sense? How will it help the cause of conservation? $100bn, give or take, sounds like an affordable loss - just a quarter, an eighth or less (depending on your estimate) of the cost to date of the recent Iraq war.
Another way of thinking is outlined in an article titled The Stuff of Legends from Jeremy Seabrook:
It is not the salvaging of the social and economic system that should be at the heart of the current emergency, but a reassurance that the resource base upon which all systems depend will be conserved, so that it may provide a secure sufficiency for all humanity for an indefinite future.
This cannot be assured by horror stories about the monetary cost, by technological fixes, by faith in conquering other worlds, by belief in the redemptive capacity of science, or the ingenuity of humanity to promote limitlessness in a bounded world. It requires an alternative and convincing story of survival, an energising myth that will inspire collective action, a narrative that tells of a different kind of emancipation.