SRS, I think many of the technologies that would reduce or mitigate global warming are needed to cause that doubling of GDP. Such as cheaper/more efficient energy and fuel. I don't think you can separate the issues.
If not from there, where will the GDP increase come from? Inflation? As we've seen, a lot of the GDP increase over the last few years has been artificial in terms of financial 'paper gains' that evaporate when the debts are called in during a recession.







