It's about risk, not certainty
@Ministry of Truth "To assume that any existing model covers all the bases is foolish." - Climate scientists have never claimed that. Their papers, and the summary reports from the IPCC, are full of risk analyses, of probabilities, of self-criticism.
The Climate Science is and always has been our current best knowledge. Yes, we should try and improve that knowledge. Yes, that means funding more science, doing more checking. It means paying for more temperature stations (see recent article in the Economist about lack of funding for that).
But meanwhile, we have to decide what to do next given what we know so far. We can decide to geoengineer the climate by digging up fossil fuels and burning them. Or we can decide to become more efficient and to use nuclear power, to use various sorts of solar power and wind power.
The current best peer-reviewed evidence we have, and economic analyses associated with it, show that the latter is the wise course in terms of sustaining our civilisation.
You will never have certainty about predicting the future. But it doesn't matter, you still have to choose an action.