The U.S. could significantly slash its greenhouse-gas emissions “at manageable costs to the economy,” says a new study from consulting firm McKinsey & Company. Assuming no significant change in consumer lifestyle, researchers did an in-depth cost-benefit analysis of various options for reducing GHG emissions. Their conclusions: “clean coal” is expensive and unproven, increasing renewable energy sources would make a relatively modest contribution, and raising efficiency of buildings, appliances, and automobiles would be the easiest and, in the end, cheapest way to do the job. The key would be to incentivize manufacturers and builders to boost efficiency, says the study, as shortsighted consumers are swayed more by cheap upfront costs than by products that save them money down the line. Implementation of a relatively cheap, entirely doable plan to reduce GHG emissions “will require strong, coordinated, economywide action that begins in the near future,” says the report. We’ll get right on that.