China and India joined almost all other major greenhouse gas emitters Tuesday in signing up to the climate accord struck in Copenhagen, boosting a deal strongly favored by the United States.

More than 100 nations have now endorsed the Copenhagen Accord, a non-binding agreement reached after two weeks of tortuous wrangling at a 194-nation summit in December.

The accord plans $100 billion a year in climate aid for developing nations from 2020 and seeks to limit global warming to below 2 degrees Celsius (3.6F) above pre-industrial times, but produced no timetable of emission limits to reach that goal.