the crux of the matter

The crux of the Planetarian position is that we should implement policies that our descendants, looking back from a distance of two or three centuries, would be grateful for.  In many cases, it's probably impossible to know what such policies would be.  In the case of global warming, however, isn't it obvious that they would want us to ameliorate it as much as possible?  Now, how should we go about doing that?