After virtually abandoning the issue for three decades, the environmental movement got a bold reality check this week from a new book highlighting relentless human population growth as a driving force behind global warming.

This wouldn’t have raised eyebrows in the 1970s, when the modern environmental movement had its genesis and Paul Erlich’s “The Population Bomb” was on just about everybody’s bookshelf.

Since then, however, overpopulation has dropped from the vocabulary of most environmentalists despite a near doubling of the world’s numbers to an estimated 6.8 billion people today.

A UN report has issued a desertification warning saying tens of millions of people could be driven from their homes, particularly in sub-Saharan Africa and Central Asia.

Without action, 50 million people could be displaced within 10 years.

Accused of scaremongering for taking climate change before the UN Security Council last week, Britain is standing firm in insisting it’s a global challenge that must not be allowed to degenerate into regional bickering.

Scientists say an “Asian haze” of pollution from rapid industrialization is boosting storms in the Pacific and having profound impacts that may be felt as far away as the Arctic.