London being underwater won't prove anything
Well, unless we have cut our CO2 emissions before then, in which case it proves cutting was pointless as far as climate change is concerned. (Reducing reliance on religious nutters is a good idea though)
In chaotic systems it's rather difficult to prove "If we had done X in the past we'd have Y result by now." - there's the same problem in economics, and that much easier to measure!
I have still not seen any evidence showing that meeting the CO2 targets would actually have a notable effect on global temperatures at all - nobody even appears to have published a "Carry on!" against "Kyoto" (or whatever agreement) prediction.
Not sure what that implies - possibly that it really won't make much of a difference, which may be why China can't be bothered. People won't forgo jam today if there's no chance of jam tomorrow no matter what.
(Pie in the sky when you die works. Hell and damnation regardless of your actions? That's a hard sell!)
Some politicians talk of us being on a cliff edge, but that seems to have been approaching for a decade so...
There seems a dearth of checking of the predictions at all really - for example, use the 'best' model with the data up until 1990 to predict 1990 to 2010, and compare against what happened in reality.
- I'm really hoping that this latter was done and is just buried in the publications that us mere mortals cannot read, but I would expect it to have been made public by one side or the other if it matched particularly well or badly, which implies it was probably inconclusive each time or just never done.
For a long time there has been an appearance of a requirement for the "science" to give the "right" answer if they want funding next year, so is it any wonder there is so little trust?
It's a mess, and it's the politicians and lobbyists who made the mess, and made the science so hard to do properly.