It's crunch time: we lose civilization or initiate an emergency zero carbon plan now.
It is now clear that the incremental-adjustment 2°C strategy has run out of time, if for no other reason than the "budget" for burning more fossil fuels is now zero, yet the global economy is still deeply committed to their continuing widespread use.
We all wish the incremental-adjustment 2°C strategy had worked, but it hasn't. It has now expired as a practical plan.
... on-going greenhouse emissions associated with food production and deforestation are often conveniently pushed to one side in discussing carbon budgets. UK scientists have shown that if some reasonably optimistic assumptions are made about deforestation and food-related emissions for the rest of the century, then most emission reduction scenarios are incompatible with holding warming to +2ºC, even with a high 50% probability of exceeding the target. In other words, food and deforestation has taken up the remaining budget, leaving no space for fossil fuel emissions.
We now have a choice to make: accept much higher levels of warming of 3–5°C that will destroy most species, most people and most of the world's ecosystems; a set of impacts some more forthright scientists say are incompatible with the maintenance of human civilisation.
Or we can conceive of a safe-climate emergency-action approach...