A bill to create the first national limit on greenhouse-gas emissions was approved by a House committee yesterday after a week of late-night debates that cemented the shift of climate change from rhetorical jousting to a subject of serious, if messy, Washington policymaking.

The legislation would create a cap-and-trade system: Over the next decades, power plants, oil refineries and manufacturers would be required to obtain allowances for the pollution they emit. Those who need more or less could turn to a Wall-Street-like market in the allowances. The 33 to 25 vote was a major victory for House Democrats, who had softened and jury-rigged the bill to reassure manufacturers and utilities — and members of their own party from the South and Midwest — that they would not suffer greatly.