I just wanted to add to the discussion that you have two assumptions that aren't necessary true: 1. that we haven't found the solutions yet to save the earth (we have), and 2. that a scientific / technologic solution is what will save us from ourselves (if only we can create a CO2 converter or some reasoning like that). I understand your frustration at our inability to work towards solutions regarding environmental problems, but I don't think 'putting all scientists on it' will be the way to get there.
Exactly: we do have the means to make this planet into a paradise instead of the partial hellhole it is today, but we as a species lack the (political) will to do so, and as far as 2) goes, I don't think science is the be-all and end-all of our problems though it might help a lot. I'm merely stating that the funds for a mission like this could have been used to save many lives.