The human population is living far beyond its means and inflicting damage to the environment that could pass points of no return, according to a major report issued Thursday by the United Nations.
Climate change, the rate of extinction of species and the challenge of feeding a growing population are putting humanity at risk, the UN Environment Program said in its fourth Global Environmental Outlook since 1997.
“The human population is now so large that the amount of resources needed to sustain it exceeds what is available at current consumption patterns,” Achim Steiner, the executive director of the Environment Program, said in a telephone interview.
Many biologists and climate scientists have concluded that human activities have become a dominant influence on Earth’s climate and ecosystems. But there is still a range of views on whether the changes could have catastrophic effects, as the human population heads toward 9 billion by midcentury.
The world population has been increasing, to 6.7 billion from 5 billion two decades ago. And the land available to each person has long been shrinking, to 5 acres in 2005 from 19.5 acres in 1900, the report said.
Population growth combined with unsustainable consumption has produced an increasingly stressed planet where natural disasters and environmental degradation endanger people, plants and animal species.
Persistent problems include a rapid rise of “dead zones,” where marine life no longer can be supported because pollutants such as runoff fertilizers deplete oxygen.
But Steiner said that Western European governments had taken effective measures to reduce air pollutants, that Brazil had made efforts to roll back some deforestation and that an international treaty to tackle the hole in Earth’s ozone layer had led to the phasing out of 95 percent of ozone-damaging chemicals.
“Life would be easier if we didn’t have the kind of population 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 human well-being and make more rational use of the resources we have on this planet.”
He said that parts of Africa could reach an environmental tipping point if changing rainfall patterns turn semi-arid zones into arid zones and make agriculture much harder. Another tipping point could occur in India and China, he said, if Himalayan glaciers shrink so much that they no longer supply adequate amounts of water.
He also warned of a global collapse by 2050 of all species being fished, if fishing continues at its current pace. In the spirit of the UN report, President Nicolas Sarkozy of France outlined plans Thursday to fight climate change.
He said he would make 1 billion euros, or $1.4 billion, available over four years to develop energy sources and maintain biodiversity. He said spending on nuclear research would be matched by spending on research into clean technologies and environmental protection.