Chimes to stop the changing clime

The sound of church bells ringing often signals celebration. But this week, outside at least 30 Episcopal churches in New England, it will also herald an impending danger -- global warming.

In a campaign to raise awareness about a changing climate, churches in Massachusetts, Connecticut, and New Hampshire pledged to each ring their church bells 350 times in a row at some point before the end of the month. Scientists have warned that the earth's atmospheric concentration of carbon dioxide must be reduced to 350 parts per million or lower to stave off the worst impacts of global warming. Current levels of carbon dioxide in the atmosphere are now estimated at more than 385 parts per million.

The campaign, run by the grassroots organization 350.org, aimed to sign up hundreds of churches across New England. 350.org is a youth-led global movement to address global warming.

Old North Church in Boston’s North End will ring its bell following its services on Sunday, and St. Peter’s Church in Weston rang its bells Monday evening.