Newspaper article International New York Times

Mass Extinction, by Our Own Hand

Newspaper article International New York Times

Mass Extinction, by Our Own Hand

Article excerpt

Al Gore reviews "The Sixth Extinction," by The New Yorker science writer Elizabeth Kolbert.

The Sixth Extinction. An Unnatural History. By Elizabeth Kolbert.Illustrated. 319 pages. Henry Holt & Company. $28.

Over the past decade, Elizabeth Kolbert has established herself as one of our very best science writers. She has developed a distinctive and eloquent voice of conscience on issues arising from the extraordinary assault on the ecosphere, and those who have enjoyed her previous works like "Field Notes From a Catastrophe" will not be disappointed by her powerful new book, "The Sixth Extinction: An Unnatural History."

Ms. Kolbert, a staff writer at The New Yorker, reports from the front lines of the violent collision between civilization and our planet's ecosystem: the Andes, the Amazon rain forest, the Great Barrier Reef -- and her backyard. In lucid prose, she examines the role of man-made climate change in causing what biologists call the sixth mass extinction -- the current spasm of plant and animal loss that threatens to eliminate 20 to 50 percent of all living species on earth within this century.

Extinction is a relatively new idea in the scientific community. Well into the 18th century, people found it impossible to accept the idea that species had once lived on earth but had been subsequently lost. Scientists simply could not envision a planetary force powerful enough to wipe out forms of life that were common in prior ages.

In the same way, and for many of the same reasons, many today find it inconceivable that we could possibly be responsible for destroying the integrity of our planet's ecology. There are psychological barriers to even imagining that what we love so much could be lost -- could be destroyed forever. As a result, many of us refuse to contemplate it. Like an audience entertained by a magician, we allow ourselves to be deceived by those with a stake in persuading us to ignore reality.

For example, we continue to use the world's atmosphere as an open sewer for the daily dumping of more than 90 million tons of gaseous waste. If trends continue, the global temperature will keep rising, triggering "world-altering events," Ms. Kolbert writes. According to a conservative and unchallenged calculation by the climatologist James Hansen, the man-made pollution already in the atmosphere traps as much extra heat energy every 24 hours as would be released by the explosion of 400,000 Hiroshima-class nuclear bombs.

The resulting rapid warming of both the atmosphere and the ocean, which Ms. Kolbert notes has absorbed about one-third of the carbon dioxide we have produced, is wreaking havoc on earth's delicately balanced ecosystems. It threatens both the web of living species with which we share the planet and the future viability of civilization. "By disrupting these systems," Ms. Kolbert writes, "we're putting our own survival in danger."

The earth's water cycle is being dangerously disturbed, as warmer oceans evaporate more water vapor into the air. Warmer air holds more moisture (there has been an astonishing 4 percent increase in global humidity in just the last 30 years) and funnels it toward landmasses, where it is released in much larger downpours, causing larger and more frequent floods and mudslides.

The extra heat is also absorbed in the top layer of the seas, which makes ocean-based storms more destructive. Just before Hurricane Sandy, the area of the Atlantic immediately windward from New York City and New Jersey was up to nine degrees warmer than normal. And just before Typhoon Haiyan hit the Philippines, the area of the Pacific from which it drew its energy was about 5.4 degrees above average.

Our oceans, a crucial food source for billions, have become not only warmer but also more acidic than they have been in millions of years. They struggle to absorb excess heat and carbon pollution -- which is why, as Ms. Kolbert points out, coral reefs might be the first entire ecosystem to go extinct in the modern era. …

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