Sir, As you report (“Climate change disaster can be averted, say experts”, Sep 19), a new study suggests that the world is not yet beyond the point of no return in its efforts to avoid global warming of more than 1.5 C, a main aspiration of the Paris agreement on climate change. Although this target still appears feasible it remains very challenging, and we will succeed only if there is strong progress on emissions reductions by countries across the world. Our understanding of future climate change will continue to evolve, and uncertainties will remain, but this is a problem of managing extreme risks, and it is clear that delaying action, locking in our dependence on fossil fuels and hoping for the best would be extremely