When it comes to climate-change regulations, the U.S. government may be on the sidelines, but that fortunately doesn’t mean American companies aren’t already reducing their greenhouse-gas emissions. The real work on climate change in America is being done at the state and local level and, increasingly, in the boardroom.

At the tail end of a two-week international conference on climate change, the United States begrudgingly agreed to participate in talks about steps that could be taken to reduce emissions. The goal of the Montreal conference was to begin planning for greenhouse gas emissions reductions beyond 2012, when the Kyoto Protocol expires. Because it has not ratified the Kyoto agreement, the United States was largely on the sidelines.

President Bush has long argued that mandated reductions in emissions will harm the U.S. economy. That thinking was shared by the Senate, which voted overwhelmingly to reject the Kyoto agreement in 1997. Since then, senators this summer voted 54-43 in favor of a non-binding resolution calling for a national program of mandatory limits and incentives to reduce greenhouse gas emissions.

Still, many U.S. companies are reducing emissions and investing in new technologies because their shareholders, not the federal government, are requiring it. Reducing emissions now, before it is mandated, makes perfect business sense because it saves money and positions companies for the future, say many CEOs. But, they add, they want national standards for predictability and consistency.

International Paper Co., the country’s largest paper company, has cut its carbon dioxide emissions and its costs by increasing its use of wood waste to fuel its operations. “It doesn’t matter whether carbon emissions reductions are mandated or not,” David Struhs, the company’s vice president of environmental affairs, told BusinessWeek. “Everything we’re doing makes sense to our shareholders and to our board, regardless of what direction the government takes.”

DuPont now uses 7 percent less energy that it did in 1990, saving the company $2 billion while producing 30 percent more goods than in 1994 when it began its emissions reductions program. The company has also reduced greenhouse gas emissions by more than 40 percent since then. Even coal-burning utilities are changing their technologies before they are required to.

In the absence of federal rules, state and local governments are filling the void. Maine, which has its own climate action plan, has joined with eight Northeastern states to develop a plan to cut greenhouse gas emissions by 10 percent by 2020. It would do so with a cap-and-trade system for greenhouse gases that rewards efficient use of fossil fuels and provides incentives for innovation. Massachusetts Gov. Mitt Romney has backed away from the plan echoing the president’s concerns about negative consequences for businesses.

From the U.S. perspective, the Montreal meeting was less important than meetings taking place in boardrooms and state capitals across the country.