In 2005, Maine and eight other northeastern and mid-Atlantic states banded together to create the Regional Greenhouse Gas Initiative to reduce carbon emissions.

The initiative is a form of carbon pricing. It sets an annual cap on the total amount of carbon dioxide emissions allowed for the collection of all large electricity power plants located in these states, a cap that declines over time.

To ensure that the cap is not breached, a limited number of authorizations to emit — called allowances — that are compatible with the cap are sold at an annual auction. Each allowance entitles a power plant to emit one ton of CO2, and every large plant has to buy and surrender to the regulators the number of allowances equal to their emissions.

The revenue from the auctions goes back to the states, where the power plants are located and the majority of it is used to incentivize energy efficiency investments. In Maine, this revenue — more than $83 million at last count — is a major source of funding for Efficiency Maine.

Because the initiative is currently in one of its periodic reviews, it is a good time to take a look at how this program has stood the test of time. At its inception, its proponents expected it to achieve modest reductions at a modest cost, while its detractors expected it to be an ineffective emissions-reducer and a jobs killer to boot.

It turns out they were both wrong. It achieved large reductions, it stimulated the economy and it was a job creator.

Within Regional Greenhouse Gas Initiative states, fuel-switching, improved energy efficiency and growing renewable energy output have caused emissions to drop by 37 percent since it was launched. During that time, member states have reduced emissions more than other states while member states saw their economies grow at a faster rate and a net increase of more than 28,000 new job-years.

Meanwhile, Maine’s use of its share of auction proceeds to fund Efficiency Maine has lowered energy bills, which have helped Maine businesses to become more competitive and homeowners to have more affordably comfortable homes.

This evidence is significant and timely. Studies make it clear that delay in acting on climate change not only significantly raises the cost of taking action, but it also raises the economic damages caused by the resulting additional emissions. Since some of the CO2 will remain in the atmosphere for thousands of years, the window of opportunity for cost-effective action is closing as the carbon levels in the atmosphere grow to threatening levels.

A place to start is the board’s current deliberations about how much the emissions should decline in the future. One of the specific proposals under consideration is to raise the annual target for emissions reductions to 5 percent from the current 2.5 percent. Even this would be a modest target because emissions in member states have been falling more than 5 percent a year, consistently exceeding the current target.

Next it would be necessary to extend the scope of existing or new carbon pricing programs, as Canada has just done. The expanded scope would include other sources and greenhouse gases — remember, it applies only to carbon emissions from power plant — and other states and regions.

The good news is that recent polls have indicated that a majority of Democrats and Republicans want to take action on climate change. What about the minority who doesn’t agree with the scientists on climate change, but do have political power?

In situations like this, it is instructive to look at the cost of being wrong. If those who reject climate science are wrong and we don’t take action, the ensuing climate damages would certainly be serious and potentially could be catastrophic. But if the scientists are wrong and we take action earlier than necessary, experience and forecasts suggest the costs likely would be small and well justified by the assurance of lower risk.

Given these choices, it should be possible to find common ground among people who have at least some aversion to risk. I don’t think any generation wants to be labeled as the generation that blew the last best chance to save the planet from irreversible, massive climate damages.

Tom Tietenberg is the Mitchell Family Professor of Economics, emeritus, at Colby College in Waterville. He has spent over 30 years working with Democrats and Republicans and their international counterparts to craft mutually acceptable, cost-effective, market-based programs to control pollution.