donderdag 28 juni 2012

A bleak prospect for our children

By Stephanie Pappas, LiveScience Senior Writer

This composite image uses a number of swaths of the Earth's surface taken on January 4, 2012.

Earth is rapidly headed toward a catastrophic breakdown if humans don't get their act together, according to an international group of scientists.
Writing Wednesday (June 6) in the journal Nature, the researchers warn that the world is headed toward a tipping point marked by extinctions and unpredictable changes on a scale not seen since the glaciers retreated 12,000 years ago.
"There is a very high possibility that by the end of the century, the Earth is going to be a very different place," study researcher Anthony Barnosky told LiveScience. Barnosky, a professor of integrative biology from the University of California, Berkeley, joined a group of 17 other scientists to warn that this new planet might not be a pleasant place to live.
"You can envision these state changes as a fast period of adjustment where we get pushed through the eye of the needle," Barnosky said. "As we're going through the eye of the needle, that's when we see political strife, economic strife, war and famine." [Top 10 Ways to Destroy Earth]

The danger of tipping
Barnosky and his colleagues reviewed research on climate change, ecology and Earth's tipping points that break the camel's back, so to speak. At certain thresholds, putting more pressure on the environment leads to a point of no return, Barnosky said. Suddenly, the planet responds in unpredictable ways, triggering major global transitions.
The most recent example of one of these transitions is the end of the last glacial period. Within not much more than 3,000 years, the Earth went from being 30 percent covered in ice to its present, nearly ice-free condition. Most extinctions and ecological changes (goodbye, woolly mammoths) occurred in just 1,600 years. Earth's biodiversity still has not recovered to what it was.
Today, Barnosky said, humans are causing changes even faster than the natural ones that pushed back the glaciers — and the changes are bigger. Driven by a 35 percent increase in atmospheric carbon dioxide since the start of the Industrial Revolution, global temperatures are rising faster than they did back then, Barnosky said. Likewise, humans have completely transformed 43 percent of Earth's land surface for cities and agriculture, compared with the 30 percent land surface transition that occurred at the end of the last glacial period. Meanwhile, the human population has exploded, putting ever more pressure on existing resources. [7 Billion Population Milestones]
"Every change we look at that we have accomplished in the past couple of centuries is actually more than what preceded one of these major state changes in the past," Barnosky said.

Backing away from the edge
The results are difficult to predict, because tipping points, by their definition, take the planet into uncharted territory. Based on past transitions, Barnosky and his colleagues predict a major loss of species (during the end of the last glacial period, half of the large-bodied mammal species in the world disappeared), as well as changes in the makeup of species in various communities on the local level. Meanwhile, humans may well be knotting our own noose as we burn through Earth's resources.
"These ecological systems actually give us our life support, our crops, our fisheries, clean water," Barnosky said. As resources shift from one nation to another, political instability can easily follow.
Pulling back from the edge will require international cooperation, Barnosky said. Under business-as-usual conditions, humankind will be using 50 percent of the land surface on the planet by 2025. It seems unavoidable that the human population will reach 9 billion by 2050, so we'll have to become more efficient to sustain ourselves, he said. That means more efficient energy use and energy production, a greater focus on renewable resources, and a need to save species and habitat today for future generations.
"My bottom line is that I want the world in 50 to 100 years to be at least as good as it is now for my children and their children, and I think most people would say the same," Barnosky said. "We're at a crossroads where if we choose to do nothing we really do face these tipping points and a less-good future for our immediate descendents."

Unfortunately the Rio+20 conference once more ended with hollow promises and no firm actions. To keep within the 2° C mean temperature rise (which is too much according to many!) it is known how much total CO² emissions until 2050 is "allowed"... and that amount will be all used-up by 2023. :-(

You might consider it the greatest and most infamous of all Ponzi Schemes!

Let *me* add a very grim tale of population growth and -collapse; all the way to extinction!

During World War II, while trying to stock a remote island in the Bering Sea with an emergency food source, the U.S. Coast Guard set in motion a classic experiment in the boom and bust of a wildlife population.
The island was St. Matthew, an unoccupied 32-mile long, four-mile wide sliver of tundra and cliffs in the Bering Sea, more than 200 miles from the nearest Alaska village. In 1944, the Coast Guard installed a loran (long range aids to navigation) station on St. Matthew to help captains of U.S. ships and aircraft pilots pinpoint their locations. The Coast Guard stationed 19 men on St. Matthew Island to operate the station. Those men—electrical technicians, cooks, medics, and others—made up the entire human population of the island.
In August 1944, the Coast Guard released 29 reindeer on the island as a backup food source for the men. Barged over from Nunivak Island, the animals landed in an ungulate paradise: lichen mats four inches thick carpeted areas of the island, and the men of the Coast Guard station were the reindeer’s only potential predators.
The men left before they had the chance to shoot a reindeer. With the end of World War II approaching, the Coast Guard pulled the men from the island. St. Matthew’s remaining residents were the seabirds that nest on its cliffs, McKay’s snow buntings and other ground-nesting birds, arctic foxes, a single species of vole, and 29 reindeer.
St. Matthew then had the classic ingredients for a population explosion—a group of healthy large herbivores with a limited food supply and no creature above them in the food chain. That’s what Dave Klein saw when he visited the island in 1957.
Klein was then a biologist working for U.S. Fish and Wildlife Service. He is now a professor emeritus with the University of Alaska Fairbanks’ Institute of Arctic Biology. The first time he hiked the length of St. Matthew Island in 1957, he and field assistant Jim Whisenhant counted 1,350 reindeer, most of which were fat and in excellent shape. Klein noticed that reindeer had trampled and overgrazed some lichen mats, foreshadowing a disaster to come.
Klein did not get a chance to return to the island until the summer of 1963, when a Coast Guard cutter dropped him and three other scientists off on the island. As their boots hit the shore, they saw reindeer tracks, reindeer droppings, bent-over willows, and reindeer after reindeer.
“We counted 6,000 of them,” Klein said. “They were really hammering the lichens.”
The herd was then at a staggering density of 47 reindeer per square mile. Klein noted the animals’ body size decreased since his last visit, as had the ratio of yearling reindeer to adults. All signs pointed to a crash ahead.
Other work commitments and the difficulty of finding a ride to St. Matthew kept Klein from returning until the summer of 1966, but he heard a startling report from men on a Coast Guard cutter who had gone ashore to hunt reindeer in August 1965—the men had seen dozens of bleached reindeer skeletons scattered over the tundra.
When Klein returned in the summer of 1966, he, another biologist and a botanist found the island covered with skeletons; they counted only 42 live reindeer, no fawns, 41 females and one male with abnormal antlers that probably wasn’t able to reproduce. During a few months, the reindeer population of St. Matthew had dropped by 99 percent.
By piecing together clues found amid the bones, Klein figured that thousands of reindeer starved during the winter following his last visit, when he counted 6,000 animals on the island. Weather records from St. Paul and Nunivak islands for the winter of 1963-1964 showed an extreme winter in both cold and amount of snowfall.
With no breeding population, the reindeer of St. Matthew Island died off by the 1980s. The unintended experiment in population dynamics and range ecology ended as it began—with winds howling over the green hills of a remote island in the Bering Sea, a place where arctic foxes are once again the largest mammals roaming the tundra.

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