BOSTON (AP) — The Boston City Council has unanimously approved an ordinance that addresses climate change by requiring all buildings larger than 20,000 square feet to eliminate carbon emissions by 2050. Acting Mayor Kim Janey intends to sign the proposal approved Wednesday. Councilor Matt O’Malley was the driving force behind the measure. O’Malley says the ordinance sets aggressive but achievable goals. It applies to about 3,500 commercial and residential buildings. A group that represents developers and building owners worked with the city on the measure. Environmental groups also welcomed the ordinance.