By James Kanter
Published:Thursday, October 25, 2007
PARIS — The human population is living far beyond itsmeans and inflicting damage on the environment that could pass points of noreturn, according to a major report issued Thursday by the United Nations.
Climate change, the rate of extinction of species and thechallenge of feeding a growing population are among the threats puttinghumanity at risk, the UN Environment Program said in its fourth GlobalEnvironmental Outlook since 1997.
"The human population is now so large that the amountof resources needed to sustain it exceeds what is available at currentconsumption patterns," Achim Steiner, the executive director of theprogram, said in a telephone interview. Efficient use of resources and reducingwaste now are "among the greatest challenges at the beginning of 21stcentury," he said.
The program described its report, which is prepared by 388experts and scientists, as the broadest and deepest of those that the UN issueson the environment and called it "the final wake-up call to theinternational community."
Over the past two decades the world population has increasedby almost 34 percent to 6.7 billion from 5 billion; similarly, the financialwealth of the planet has soared by about a third. But the land available toeach person on earth had shrunk by 2005 to 2.02 hectares, or 5 acres, from 7.91hectares in 1900 and was projected to drop to 1.63 hectares for each person by2050, the report said.
The result of that population growth combined withunsustainable consumption has resulted in an increasingly stressed planet wherenatural disasters and environmental degradation endanger millions of humans, aswell as plant and animal species, the report said.
Steiner said that demand for resources was close to 22hectares per person, a figure that would have to be cut to between 15 and 16hectares per person to stay within existing, sustainable limits.
Persistent problems identified by the report include a rapidrise of so-called dead zones, where marine life no longer can be supportedbecause of depletion of oxygen caused by pollutants like fertilizers. Alsoincluded is the resurgence of diseases linked with environmental degradation.
The report is being published two decades after a commissionheaded by the former Norwegian prime minister Gro Harlem Brundtland warned thatthe survival of humanity was at stake from unsustainable development.
Steiner said many of the problems identified by theBrundtland Commission were even more acute because not enough had been done tostop environmental degradation as flows of goods, services, people,technologies and workers had expanded, even to isolated populations.
He did, however, identify some reasons for hope that pointedtoward better environmental stewardship.
He said West European governments had taken effectivemeasures to reduce air pollutants, and he praised efforts in parts of Brazil toroll back deforestation in the Amazon. He said an international treaty totackle the hole in the earth's ozone layer had led to the phasing-out ofrelease of 95 percent of ozone-damaging chemicals.
Steiner said more intelligent management of scarce resourcesincluding fishing grounds, land and water was needed to sustain a still largerglobal population, which he said was expected to stabilize at between 8 billionand 10 billion people.
"Life would be easier if we didn't have the kind ofpopulation growth rates that we have at the moment," Steiner said."But to force people to stop having children would be a simplistic answer.The more realistic, ethical and practical issue is to accelerate humanwell-being and make more rational use of the resources we have on this planet."
Steiner said environmental tipping points, at whichdegradation can lead to abrupt, accelerating or potentially irreversiblechanges, would increasingly occur in locations like particular rivers orforests, where populations would lack the ability to repair damage because thegravity of a problem would be far beyond their physical or economic means.
Looking ahead, Steiner said parts of Africa could reachenvironmental tipping points if changing rainfall patterns stemming fromclimate change turned semi-arid zones into arid zones, and made agriculturethat sustained millions of people much harder.
Steiner said other tipping points triggered by climatechange could occur in areas like India and China if Himalayan glaciers shrankso much that they no longer supplied adequate amounts of water to populationsin those countries.
He also warned of a global collapse of all species beingfished by 2050, if fishing around the world continued at its present pace.
The report said 250 percent more fish are being caught thanthe oceans can produce in a sustainable manner, and that the number of fishstocks classed as collapsed had roughly doubled to 30 percent globally over thepast 20 years.
The report said that current changes in biodiversity werethe fastest in human history, with species becoming extinct a hundred times asfast as the rate in the fossil record. It said 12 percent of birds werethreatened with extinction; for mammals the figure was 23 percent and foramphibians it was more than 30 percent.
"Scientists now refer to a sixth major extinctioncrisis that's under way," Steiner said.
The first mass extinction, about 440 million years ago, andthe four succeeding extinctions were the result of physical shocks to theplanet like volcanic eruptions and plate tectonic shifts.
The report said that annual emissions of CO2 from fossilfuels have risen by about one-third since 1987 and that the threat from climatechange now was so urgent that only very large cuts in greenhouse gases of 60 to80 percent could stop irreversible change.
The effects of global warming, like the melting ice in theArctic are "accelerating at a pace that goes beyond the scenarios andmodels we've been using," Steiner said.
Climate change, however, was an issue that gained hugemomentum over the past year, with governments, industries and citizensincreasingly seeking solutions to the problem, Steiner said. The recent awardof the Nobel Peace Prize to the Intergovernmental Panel on Climate Change andto former Vice President Al Gore was a sign of widespread scientific consensusthat climate change is under way, he said.
Steiner called for an accelerated effort on a far widerrange of environmental issues to build the same sense of urgency as shown onclimate change over the past year to address the worsening situations ofbiodiversity, land degradation, fisheries and freshwater.
Many biologists and climate scientists have concluded thathuman activities have become a dominant influence on the planet's climate andecosystems. But there is still a range of views on whether this could result ina catastrophic unraveling of natural resources as the human population headstoward nine billion by midcentury, or more of a steady diminution in diversity.