The Paris Climate deal addresses 1pc of the problem. How is that a victory?

The  Paris deal promises to keep temperature rises below 2°C. However, the actual promises made here will do almost nothing to achieve that. It is widely accepted that to keep temperature rises below 2°C, we have to reduce CO₂ emissions by 6,000Gt. The UNFCCC estimates that if every country makes every single promised Paris deal carbon cut by 2030 to the fullest extent possible and there is no carbon leakage, CO₂ emissions will be cut by 56 Gt by 2030.

The maths is simple: in an implausibly optimistic best-case scenario, Paris leaves 99pc of the problem in place. To say that Paris will get us to “well below 2°C” is cynical posturing at best. It relies on wishful thinking. It’s like going on a diet to slim down, but declaring victory after the first salad.

Paris will be extraordinarily costly. It is likely this is the most expensive treaty in the history of the world. Using the best individual and collectively peer-reviewed energy-economic models, the total cost of Paris – through slower GDP growth from higher energy costs – will reach $1-2 trillion every year from 2030.