Who's afraid of CO2?

The increase in atmospheric carbon dioxide has spurred dramatic growth in Amazon rain forests, which have been expanding by two tons of biomass per acre per year.

FOR BAD news, you can't top El Niño. Week in, week out, it's been one story after another on the anomalous weather pattern's dire effects, especially in California. Pounding rainstorms have washed out highways, triggered mudslides, ruined crops, displaced thousands of residents. A few weeks ago, Governor Pete Wilson estimated damages in his state at $ 300 million. Some experts fear the toll will hit $1 billion.

A disaster all around, right?

Actually — wrong.

"El Niño Blows $6 billion into the economy," reads the headline on the March World Climate Report, a newsletter that tracks the science and politics of global climate issues. El Niño has tragically brought wreckage and ruin to some, the editors write, but "what got lost here are the remarkable benefits" it has brought to most.

To begin with, El Niño meant an unusually warm January and February for much of the Midwest and Northeast — a windfall for cities that typically spend millions of dollars each winter on snow removal. There has been a 10 percent drop in energy used for heating, a savings of $5 billion off the nation's heating bill. Thank you, El Niño.

Construction employment is up because mild temperatures gave the building season an early start. Sales of light clothing and garden supplies are running ahead of average, too.

Another El Niño effect — the suppression of tropical storms and hurricanes — has chopped at least $1 billion from the usual damage toll. And even the rains in the West have done some economic good: By enabling hydroelectric plants to run at full capacity, they have driven down the price of oil and gas — a boon for every major fuel user. "If El Niño doesn't have something to do with the phenomenal rise . . . in the Dow Jones transportation index," says World Climate Report, "we'll eat our tool-of-industry hats."

Nationwide, El Niño has been good for some $6 billion in benefits, far more than it has imposed in costs. If the climate sensationalists had you under a different impression, maybe you should be wondering what else they're getting wrong.

Global warming, say.

To hear the catastrophists tell it, a rise in the earth's temperature caused by an accumulation of greenhouse gases — mostly carbon dioxide and water — threatens an environmental doomsday. Unless we sharply curtail our use of fossil fuels, the oceans will rise, disease will spread, the polar caps will melt, wildlife will die out, and millions of human beings will starve. Global warming, they say, is the worst disaster our planet has ever faced.

No one sounds this alarm more urgently than Al Gore, who for years has championed a steep "carbon tax" to drastically force down American energy consumption.In his book Earth in the Balance, Gore writes that our "dysfunctional civilization" is "killing the atmosphere with carbon dioxide and other pollutants."

Pollutants? Carbon dioxide (CO₂) is a pollutant like water is a poison. It is one of the mainstays of life on earth. Plants cannot survive without it, just as we cannot survive without the oxygen plants exhale. Of course, too much of a good thing can be a bad thing, but how much CO₂ would be too much? Federal mine safety regulations warn that carbon dioxide in the air becomes toxic at 5,000 parts per million (ppm). Currently, CO2 concentrations in the earth's atmosphere clock in at roughly 360 ppm. Don't rush for the gas masks yet.

True, at 360 ppm, we have more CO₂ in the air than we used to; in 1940, the level was about 300 ppm. It's also true that the increase in the last 60 years is due to human activity — the vast industrial infrastructure on which modern civilization rests. Technology requires fuel, and as coal, oil, and natural gas are consumed, CO₂ is released.

But it is far from clear that human-generated CO₂ can affect the world's climate. Global temperatures fluctuate. Much of the 17th century was so cold it is known as the "Little Ice Age." For three centuries, the world has been recovering from that global cold snap; only in the last few decades has the warming finally tapered off. That's right, tapered off. The period of greatest human emissions of CO₂ has coincided with a cessation of global warming. Hard to believe? Only if you've been listening to the alarmists.

Not only isn't it necessary to curb carbon dioxide emissions, it may not even be desirable. A higher level of CO₂ in the atmosphere would mean faster growing times for plants, longer growing seasons, and a greater ability to withstand drought. Dozens of crops would produce dramatically higher yields. In just the past half-century, pine forests in the American West have shown a sharply increased growth rate. So have rain forests in the Amazon, which are growing by two tons of biomass per acre per year. More CO₂ means more vegetation. That, in turn, means more animal life. Indeed, more kinds of animal life — biodiversity — since nothing more strongly correlates with species richness than high levels of plant growth.

The spread of technology and industry, so beneficial for freedom and human living standards, is also good for Mother Nature. It unlocks carbon from deep inside the earth and makes it available for conversion into living things. A pollutant, Mr. Gore? Carbon dioxide is no pollutant. It is a life-giver.

(Jeff Jacoby is a columnist for The Boston Globe).

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