Los Angeles — Take a deep breath. Now hold it. And hold it. And hold it. . . .

The Environmental Protection Agency recently designated carbon dioxide a “pollutant.” CO2 is the same gas you and every human being emit when you exhale, talk, laugh, or sing. Plants eat CO2 for breakfast, lunch, and dinner. Too bad the Obama administration and the Democratic Congress are not populated by trees and shrubs. Human liberals lack the appreciation for CO2 that would animate politically active flora. Instead, Washington’s statists are crafting a carbon clampdown that would slash CO2 to levels best achieved with a magic wand.

Democratic Representatives Henry Waxman of California and Ed Markey of Massachusetts have introduced the American Clean Energy and Security Act. Also known as “the cap-and-trade bill,” these 648 pages of legislative swamp gas would stifle the already ailing economy with brand-new costs and regulations designed to defeat so-called global warming.

Michigan Democrat John Dingell dared to utter the truth on April 24. “Nobody in this country realizes that cap-and-trade is a tax, and a great big one.” How big? $646 billion between 2012 and 2019, according to President Obama’s budget.

Even worse, this bill aims roughly to halve CO2 levels from about 900 parts per million, the level to which they are expected to rise by 2100. Page 336 declares that analysis mandated by the bill “shall address . . . whether United States actions, in concert with international action, are sufficient to avoid . . . atmospheric greenhouse gas concentrations above 450 parts per million carbon dioxide equivalent.”

As Iain Murray explains, achieving this goal involves numbers almost too huge to count and requires projects nearly too large to contemplate. During an April 23 seminar at the Heritage Foundation’s Resource Bank, Murray — a senior fellow with the Competitive Enterprise Institute — detailed what it would take to cut Earth’s CO2 by about 50 percent by the time people party like it’s 2099.

A staggering 3,700 gigatons (3.7 trillion tons) of CO2 must be squelched worldwide until century’s end to hit this benchmark. This equals 41.1 gigatons of CO2 for each of the 90 years between 2010 and 2100.

How can mankind make this happen? Select any one of the following choices from this menu of dizzying options.

‐Increase current wind-turbine capacity 575-fold.

‐Construct 5,589 1-gigawatt nuclear power plants, producing 15 times today’s output.

‐Build 11,220 “zero emission” 500-megawatt coal-burning electrical plants.

‐Install 41,100 facilities to sequester CO2, similar to Norway’s Sleipner project. Only three comparable sites now exist.

‐Plant trees on now-barren land covering 14.2 million square miles, roughly four times the size of the United States.

CO2 hidden within a new forest’s trees would stay stashed until 2100. But wind turbines and atomic reactors age. Either of those strategies would have to be repeated periodically until the 22nd century at epic expense. Remember: Every $1 billion spent combating CO2 as if it were the swine-flu virus is $1 billion less to cure the swine flu, educate kindergartners, or feed impoverished octogenarians.

“The idea that the world can achieve these atmospheric targets at anything approaching affordable cost is quite simply fantasy,” Murray tells me. “After ten years with no temperature increase — something the climate models failed to predict — it is irresponsible in the extreme to suggest we should try to meet these targets at any cost. It would be like Gerald Ford’s flu vaccinations, which seemed like a good idea to save a few hundred lives, but ended up killing a thousand — except the human cost here could be orders of magnitude bigger.”

Two days before Murray’s presentation, Angelenos broiled in 90-degree heat. Hours after he spoke, Heritage’s guests at the posh Century Plaza Hotel huddled around the X Bar’s outdoor fire pits and struggled to stay warm amid unusually brisk evening temperatures. This confirmed an observation by one of Iain Murray’s colleagues that encapsulates the folly of this entire issue.

“Today, we call it climate change,” CEI’s Chris Horner has said. “We used to call it weather.”