Boston Globe: A groundbreaking climate change bill unveiled yesterday by leading House Democrats takes some inspiration from a pact among 10 Northeastern states that was the first in the United States to place a mandatory cap on carbon emissions and begin trading pollution allowances. The bill would set strict new limits on greenhouse gases, cutting emissions by 20 percent by 2020 and by 85 percent by 2050. Pollution credits would be given or auctioned off to utilities and businesses, and would …