The case for global-warming alarmism is melting faster than those mythical disappearing Himalayan glaciers, but Al Gore isn’t backing down.

In a long op-ed piece for The New York Times the other day, Gore cranked up the doomsday rhetoric. Human beings, he warned, “face an unimaginable calamity requiring large-scale, preventive measures to protect human civilization as we know it.” His 1,900-word essay made no mention of his financial interest in promoting such measures — Gore has invested heavily in carbon-offset markets, electric vehicles, and other ventures that would profit handsomely from legislation curbing the use of fossil fuels, and is reportedly poised to become the world’s first “carbon billionaire.” However, he did mention “global-warming pollution” no fewer than four times, declaring that “our grandchildren would one day look back on us as a criminal generation” if we don’t move decisively to reduce it.

By “global-warming pollution,” Gore means carbon dioxide (CO2), which is a “pollutant” in roughly the way oxygen and water are pollutants: Human existence would be impossible without them. CO2 is essential to photosynthesis, the process that sustains plant life and generates the oxygen that human beings and animals inhale. Far from polluting the world, carbon dioxide enriches it. Higher levels of CO2 are associated with larger crop yields, increased forest growth, and longer growing seasons — in short, with a greener planet.

Of course carbon dioxide also contributes to the greenhouse effect that keeps the earth warm. But the vast majority of atmospheric CO2 occurs naturally, and it is far from clear that the carbon dioxide contributed by human industry has a significant impact on the world’s climate.

On the other hand, it is quite clear that the economic and agricultural activity responsible for that anthropogenic CO2 has been enormously beneficial to myriads of men, women, and children. In just the last two decades, life expectancy in developing nations has climbed appreciably and infant mortality has fallen. Hundreds of millions of Indian and Chinese citizens have been lifted out of poverty. Whatever else might be said about carbon dioxide, it has helped make possible a dramatic increase in the quality of many human lives.

But there is no awareness of such tradeoffs in Gore’s latest screed. He brushes aside as unimportant the recently exposed blunders in the 2007 assessment report of the Intergovernmental Panel on Climate Change. These include claims that Himalayan glaciers could disappear by 2035, that global warming could slash African crop yields by 50 percent, and that 55 percent of the Netherlands — more than twice the correct amount — is below sea level.

Gore seems equally untroubled by Climategate, the scandal involving researchers at the University of East Anglia’s Climatic Research Unit, who apparently schemed to manipulate temperature data to prevent their critics from being published in peer-reviewed journals, and to destroy records and calculations to keep climate skeptics from double-checking them.

Both the Intergovernmental Panel on Climate Change’s errors and the Climatic Research Unit scandal have triggered major investigations, and opinion polls show a falloff in the percentage of the public that believes either global warming is cause for serious concern or that scientists see eye to eye on the issue. Yet Gore insists, against all evidence, that “the overwhelming consensus on global warming remains unchanged.”

To climate alarmists like Gore, everything proves their point. For years they argued that global warming would mean a decline in snow cover and shorter ski seasons. “Children just aren’t going to know what snow is,” one climate scientist lamented to reporters in 2000. The IPCC itself was clear that climate change was resulting in more rain and less snow.

Undaunted, Gore now claims that the blizzards that have walloped the Northeast in recent weeks are also proof of global warming. “Climate change causes more frequent and severe snowstorms,” he posted on his blog last month.

Gore is a True Believer; his climate hyperbole is less a matter of science than of faith. In almost messianic terms, he urges Congress to sharply restrain Americans’ access to energy. “What is at stake,” he writes, “is our ability to use the rule of law as an instrument of human redemption.”

But while Gore prays for redemption, the pews in the Church of Climate Catastrophe are gradually emptying. The public’s skeptical common sense, it turns out, is pretty robust. Just like those Himalayan glaciers.