Been visiting that recycling bin? Feeling a little smug about the switch from disposable to cloth diapers?

Author Bill McKibben says it's time to stop patting yourself on the back. Obsession over such details is "at best a kind of calisthenics for the race we really need to run," McKibben told a packed auditorium at East High School Monday night.Describing the perils facing Earth, McKibben outlined the radical changes in philosophy and lifestyle that humans must make if they want to save this "sweet and glorious, incredibly complicated and buzzing planet."

A staff writer for The New Yorker magazine, McKibben wrote "The End of Nature," an acclaimed and controversial book that has been translated into 15 languages. His address Monday was the first in a series of six lectures about the Earth sponsored by the Utah Museum of Natural History.

McKibben stressed the threat global warming presents to plants, trees, lakes and the 50 million species inhabiting the planet. The year 1990 was the hottest year globally since nations began recording temperatures 150 years ago, he said. The next six hottest years were all in the '80s. The drought of 1988 cut U.S. corn and soybean production by one-third that year, he said. For the first time in memory, Americans ate more grain than they grew.

"Two American summers like that in a row would result in a famine of unprecedented scale," he said.

The size and diversity of the crowd at East High School - a crowd that continued to pour into the auditorium 10 minutes after the lecture was due to start - underscored McKibben's alarm. He told the full house of worried Utahns that Earth's salvation lies in fundamental, sweeping change in the way humans view their national economies, their goals and their place in the universe.

People must shun the idea that success is measured by a standard of living that increases with each generation, bringing comfort, ease and pollution in its wake, he said.

The structure of industrialized economies must be radically altered. A U.S. recession simply means that our massive economy stopped growing, he said. That brief halt in growth sparks panic because the economy is built to survive only if it grows.

But an endless spiral of growth is not possible and brings global ruin in its wake. "It's a mindless and greedy dream that economic growth will solve the world's problems. If it could, we would have seen it in the vast economic boom since World War II."

People are naive if they think they can address global crisis with recycling. "Recycling is simply reusing the containers our immense abundance comes in," he said. We must, instead, sacrifice that abundance.

Instead of asking the "starry-eyed and idealistic" question of cloth or Pampers, ask "How many babies do I plan on diapering?" he suggested.

McKibben advocated population control as a critical element to saving the Earth. Noting that an American baby uses 35 times more resources than an African baby, he said curtailing the American population will ease the strain on our resources.

But don't make sweeping change out of fear, he suggested; make it out of love.

"If it's only fear for our own necks that drives us, it can drive us in directions as damaging as the one we are going in now. I prefer love. It is more complicated, more able. A love for the rest of creation so intense it allows us to slowly slip back into a less assertive, less dominant role."

If people don't make the sharp changes necessary, they not only watch their lakes, oceans and forests die from heat stress - they watch their own spirits wither, McKibben said.

Living on a planet ravaged by global warming, humans will lose their sense of identity, awe and connection with the divine. If the planet warms a degree a decade, as predicted, by the middle of the next century the devastation will be so great that "even though we feel crowded, there will be a sense of loneliness, a sense that there is nothing but us left in the world and that everything else lives at our sufferance," he said.

If we lose the wild of nature, we lose God, McKibben said. "Our best source of apprehending the divine and something larger than ourselves is in the natural world," he said.

As the world heats and changes under man's cloud and pollution, humans lose their chance to redeem themselves. "A generation may one day be born that can't comprehend Thoreau. They cannot find their salvation in the world's wildness because that wildness has disappeared."