RALEIGH -— On any sensible priority list for a state governor, I would argue, imposing costly new regulations to combat a phantom environmental threat would have to be at or near the bottom. Actually, a governor who cared more about results than intentions wouldn’t even have this notion anywhere on the list.

Unfortunately for the legacy of Gov. Gary Locke of Washington, who is retiring this year, he has the dubious distinction of signing into law one of the silliest state regulations ever: a requirement that any new fossil-fuel power plant in his state must offset 20 percent of its emissions of carbon dioxide. Utilities can pull this off by such policies as planting trees or helping cities transfer their bus fleets from diesel to natural gas.

The idea wasn’t original to Locke. Years earlier, Oregon enacted a 17 percent offset requirement. And to his everlasting embarrassment, new California Gov. Arnold Schwarzenegger has endorsed a similar approach in the Golden State. There is a “groundswell of support” for the measure in other states, too, according to an environmentalist quoted by the online news service Stateline.

So what do these Western governors know that the rest of America needs to learn about air quality? Nothing. Carbon dioxide, of course, is not a pollutant. It happens to be essential to the propagation of vegetable life on this planet. Every breath taken by every human being results in the release of carbon dioxide into the atmosphere, so treating it like one treats true threats to human health is ridiculous.

Proponents of the theory of human-induced global warming believe that CO2 emissions are playing a significant role in raising average global temperatures, thus generating massive calamities such as floods, droughts, rough winters, and mild winters. I’m not kidding. Virtually anything that has happened weather-wise has been attributed to the global-warming scenario, even though these assertions are mutually inconsistent. Indeed, although I can’t seem to lay my hands on it right now, U.S. News recently printed an item to the effect that increases in temperatures are causing more severe winters on much of the Earth. Yes, basically, global warming causes global cooling. And as I have noted previously, the science behind all of this is questionable, to say the least.

But even if this were a problem worth of public-policy attention, it would certainly not merit action by state governments. No state can impose regulations draconian enough truly to have a measurable impact on emissions, given the global nature of the issue. Regulations such as those just imposed by Gov. Locke are purely symbolic — but what is not symbolic is the cost, passed along to ratepayers in the form of higher energy prices.

There’s been talk of North Carolina developing a “strategy” to deal with CO2 emissions and global warming. Let’s hope our politicians in North Carolina, unlike the governors and legislators of a frightening number of other states, are all talk and no action.

Hood is president of the John Locke Foundation and publisher of Carolina Journal.