Alas, 2020 is not a rain check date, it's a prescription for disaster
Cosserat,
It's fine for us to make an intellectual agreement to revisit this in 2020 to look at the data again. But in the meantime, if you are incorrect, the results will be quite disastrous in that the continued GHG emissions for another 8 years will make the atmospheric carbon pool large enough to in all probability create climatic havoc for hundreds if not thousands of years before natural or human influences can sequester enough carbon again to make a return to pre-industrial levels. Just as a general on the battlefield has to go on incomplete information, experience, hunches and a little luck, human societies are going to have to take action before all the evidence is in on the exact forcing dynamics of climate change is completely understood. Therefore, it seems wisest to aggressively pursue reduced carbon emissions now while we have a chance to impact the processes, backing off later if and only if your predictions, however unlikely they are, turn out to be correct. Doing nothing now will not provide us an option to start that process in 2020 as you suggest would be possible if you are wrong. Such dallying could be unfortunate at best, catastrophic at worst.
