Nearly 200 nations faced a Monday deadline to file what the United Nations’ climate chief calls “among the most important policy documents governments will produce this century."

Experts say the world is heading for considerably less warming than projected a decade ago, but that good news is overwhelmed by much more pain from current climate change than scientists anticipated.

No country will see energy needs grow faster in coming decades than India, and even under the most optimistic projections part of that demand will have to be met with dirty coal power — a key source of heat-trapping carbon emissions.

This week’s climate change summit features lots of talk from different nations about their goals for reducing carbon emissions.