John McCain has joined the choir, probably by necessity, but his tune is a bit different. 

The centerpiece of McCain’s approach to slowing global warming is a nationwide “cap-and-trade” system for reducing emissions — setting an overall pollution limit, then letting individual polluters buy and sell emissions allowances within that limit.

Political minefields

But in delivering his manifesto Monday, he also stepped directly on two of the biggest ideological land mines around global warming reductions. He endorsed nuclear power and proposed to crack down on China and India if they don’t adopt similar caps to control their accelerating emissions.

McCain, like the other candidates, also avoided addressing some key questions about the impacts of his plan, including costs to electricity and natural gas ratepayers.

The Lieberman-Warner Climate Security Act, pending now before the Senate but facing a potential veto from President Bush, would require roughly comparable emissions cuts by 2020 as McCain’s plan. A recent analysis by the Energy Information Administration concluded that the bill would boost utility rates from 5 percent to 27 percent by 2020, with the range depending on how fast new emissions reduction technology develops.

McCain, Clinton and Obama all favor a cap-and-trade system, similar to that used in Europe to address global warming and in the United States to reduce acid rain pollution from coal plants. Their plans differ some: McCain’s 2050 goal is for at least a 60 percent reduction; Obama and Clinton favor 80 percent.