The crux here seems to relate to the idea that different parts of the world 1) will experience different effects of climate change, 2) different methods of farming are used in various parts of the world and 3) the strategic response to climate change will be determined by these two variables, i.e., the proper response to climage change in one area will differ from that of another area depending on what kind of farming methods are used there and what effects of climate change are being felt there. 

One unified response to climate change, according to this reading of the quote, is not appropriate. "Specific circumstances" will determine appropriate specific responses.

Critically, you could say that we have to accept that climate change is going to happen.  There are still people who refuse to accept it.  These people are starting to come around.  I think that is the purpose of the statement.

On its face, this seems like a logical statement.  It also seems like something of a truism or a platitude.  That is, it seems like it's kind of obvious but also that it has little real meaning.  All it's really saying is that climate change will cause problems and we need to work together to face those problems.  That seems fairly obvious.