Credit Christoph Niemann (This book was selected as one of The New York Times Book Review’s 10 Best Books of 2014. For the rest of the list, click.) Over the past decade, Elizabeth Kolbert has established herself as one of our very best science writers.
Kohlberg's theory of moral development offered a framework for how children form moral reasoning through a series of six key stages.
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.” 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,” 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 Kolbert notes has absorbed about one-third of the carbon dioxide we have produced, is wreaking havoc on earth’s delicately balanced ecosystems. Gotan Project La Revancha Del Tango Flac Torrent. It threatens both the web of living species with which we share the planet and the future viability of civilization. “By disrupting these systems,” 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. Advertisement 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 Kolbert points out, coral reefs might be the first entire ecosystem to go extinct in the modern era. The same extra heat pulls moisture from soil in drought-prone regions, causing deeper and longer-lasting droughts. The drying of trees and other vegetation leads also to an increase in the frequency and average size of fires. Food crops are threatened not only by more pests and the disruption of long-predictable rainy season-dry season patterns, but also by the growing impact of heat stress itself on corn, wheat, rice and other staples. Earth’s ice-covered regions are melting. The vanishing of the Arctic ice cap is changing the heat absorption at the top of the world, and may be affecting the location of the Northern Hemisphere jet stream and storm tracks and slowing down the movement of storm systems.
Meanwhile, the growing loss of ice in Antarctica and Greenland is accelerating sea level rise and threatening low-lying coastal cities and regions. Viruses, bacteria, disease-carrying species like mosquitoes and ticks, and pest species like bark beetles are now being pushed far beyond their native ranges. Everywhere the intricate interconnections crucial to sustaining life are increasingly being pulled apart.
Credit Christoph Niemann This is the world we’ve made. And in her timely, meticulously researched and well-written book, Kolbert combines scientific analysis and personal narratives to explain it to us. The result is a clear and comprehensive history of earth’s previous mass extinctions — and the species we’ve lost — and an engaging description of the extraordinarily complex nature of life.
Most important, Kolbert delivers a compelling call to action. “Right now,” she writes, “we are deciding, without quite meaning to, which evolutionary pathways will remain open and which will forever be closed. No other creature has ever managed this, and it will, unfortunately, be our most enduring legacy.” Kolbert expertly traces the “twisting” intellectual history of how we’ve come to understand the concept of extinction, and more recently, how we’ve come to recognize our role in it.
When mastodon bones were first studied, in 1739, many scientists reasoned that the large and unique bones belonged to an elephant or hippopotamus. But in 1796, the French naturalist Georges Cuvier presented evidence of an entirely new theory: The bones belonged to a lost species from “a world previous to ours.” Cuvier collected and studied as many fossils as he could, eventually identifying dozens of extinct species, and over the next several decades, with the contributions of Charles Lyell and Charles Darwin, extinction evolved as a scientific concept. Today, Kolbert writes, we are witnessing a similar mass extinction event happening in the geologic blink of an eye. According to E. Wilson, the present extinction rate in the tropics is “on the order of 10,000 times greater than the naturally occurring background extinction rate” and will reduce biological diversity to its lowest level since the last great extinction. This time, however, a giant asteroid isn’t to blame — we are, by altering environmental conditions on our planet so swiftly and dramatically that a large proportion of other species cannot adapt.
And we are risking our own future as well, by fundamentally altering the integrity of the climate balance that has persisted in more or less the same configuration since the end of the last ice age, and which has fostered the flourishing of human civilization. As early as the 1840s, scientists noticed large gaps in the fossil record — time periods in which earth’s biodiversity declined rapidly and could not be explained by a static system. Some scientists theorized that abrupt climate changes had caused past mass extinction events.
The path leads up a hill, across a fast-moving stream, back across the stream, and then past the carcass of a sheep. In my view it's raining, but here in the Southern Uplands of Scotland, I'm told, this counts as only a light drizzle, or smirr. Just beyond the final switchback, there's a waterfall, half shrouded in mist, and an outcropping of jagged rock. The rock has bands that run vertically, like a layer cake that's been tipped on its side. My guide, Jan Zalasiewicz, a British stratigrapher, points to a wide stripe of gray. 'Bad things happened in here,' he says. The stripe was laid down some 445 million years ago, as sediments slowly piled up on the bottom of an ancient ocean.
In those days life was still confined mostly to the water, and it was undergoing a crisis. Between one edge of the three-foot-thick gray band and the other, some 80 percent of marine species died out, many of them the sorts of creatures, like graptolites, that no longer exist.
The extinction event, known as the end-Ordovician, was one of the five biggest of the past half billion years. It coincided with extreme changes in climate, in global sea levels, and in ocean chemistry—all caused, perhaps, by a supercontinent drifting over the South Pole. Stratigraphers like Zalasiewicz are, as a rule, hard to impress. Their job is to piece together Earth's history from clues that can be coaxed out of layers of rock millions of years after the fact. They take the long view—the extremely long view—of events, only the most violent of which are likely to leave behind clear, lasting signals. It's those events that mark the crucial episodes in the planet's 4.5-billion-year story, the turning points that divide it into comprehensible chapters. So it's disconcerting to learn that many stratigraphers have come to believe that we are such an event—that human beings have so altered the planet in just the past century or two that we've ushered in a new epoch: the Anthropocene.
Standing in the smirr, I ask Zalasiewicz what he thinks this epoch will look like to the geologists of the distant future, whoever or whatever they may be. Will the transition be a moderate one, like dozens of others that appear in the record, or will it show up as a sharp band in which very bad things happened—like the mass extinction at the end of the Ordovician? That, Zalasiewicz says, is what we are in the process of determining. The word 'Anthropocene' was coined by Dutch chemist Paul Crutzen about a decade ago. One day Crutzen, who shared a Nobel Prize for discovering the effects of ozone-depleting compounds, was sitting at a scientific conference.
The conference chairman kept referring to the Holocene, the epoch that began at the end of the last ice age, 11,500 years ago, and that—officially, at least—continues to this day. 'Let's stop it,' Crutzen recalls blurting out. 'We are no longer in the Holocene. We are in the Anthropocene.'
Well, it was quiet in the room for a while.' When the group took a coffee break, the Anthropocene was the main topic of conversation. Someone suggested that Crutzen copyright the word. Way back in the 1870s, an Italian geologist named Antonio Stoppani proposed that people had introduced a new era, which he labeled the anthropozoic. Stoppani's proposal was ignored; other scientists found it unscientific. The Anthropocene, by contrast, struck a chord. Human impacts on the world have become a lot more obvious since Stoppani's day, in part because the size of the population has roughly quadrupled, to nearly seven billion.
'The pattern of human population growth in the twentieth century was more bacterial than primate,' biologist E. Wilson has written. Wilson calculates that human biomass is already a hundred times larger than that of any other large animal species that has ever walked the Earth. Spectralive Nxt V4 Rapidshare Free. In 2002, when Crutzen wrote up the Anthropocene idea in the journal Nature, the concept was immediately picked up by researchers working in a wide range of disciplines.
Soon it began to appear regularly in the scientific press. 'Global Analysis of River Systems: From Earth System Controls to Anthropocene Syndromes' ran the title of one 2003 paper. 'Soils and Sediments in the Anthropocene' was the headline of another, published in 2004.
At first most of the scientists using the new geologic term were not geologists. Zalasiewicz, who is one, found the discussions intriguing. 'I noticed that Crutzen's term was appearing in the serious literature, without quotation marks and without a sense of irony,' he says. In 2007 Zalasiewicz was serving as chairman of the Geological Society of London's Stratigraphy Commission. At a meeting he decided to ask his fellow stratigraphers what they thought of the Anthropocene. Twenty-one of 22 thought the concept had merit.
The group agreed to look at it as a formal problem in geology. Would the Anthropocene satisfy the criteria used for naming a new epoch? In geologic parlance, epochs are relatively short time spans, though they can extend for tens of millions of years. (Periods, such as the Ordovician and the Cretaceous, last much longer, and eras, like the Mesozoic, longer still.) The boundaries between epochs are defined by changes preserved in sedimentary rocks—the emergence of one type of commonly fossilized organism, say, or the disappearance of another. The rock record of the present doesn't exist yet, of course.
So the question was: When it does, will human impacts show up as 'stratigraphically significant'? The answer, Zalasiewicz's group decided, is yes—though not necessarily for the reasons you'd expect.