EARTH may be nearing an ecological tipping point that threatens biodiversity, food production and water supplies as humans consume resources at an unsustainable pace, according to an article to be published tomorrow in the journal 'Nature'.
About 43pc of the Earth's surface has been built upon or is being used for agriculture to support the planet's seven billion inhabitants, according to Anthony Barnosky, a professor of integrated biology at the University of California, Berkeley. As that figure approaches 50pc, there may be irreversible and significant environmental changes.
Without policy and behavioural changes, the planet's environment will suffer, Prof Barnosky said. "When that happens you get a period of societal adjustment that usually includes economic problems, wars and famines."
Humans consume 2.25 acres of resources per capita, and with the Earth's population projected to reach nine billion by 2045, half of all land may be in use by 2025, he said.
That includes Antarctica, Greenland and other mostly uninhabitable regions.
Small-scale ecosystems have shown that once 50pc of an area is altered, biodiversity is often lost and animal and plant species are at risk of extinction, he said.
There's "an urgent need" to reduce population growth and per-capita resource use, grow more food on less land and replace fossil fuels with renewable energy sources.
"It's a global society, and these are global problems, and the only way we can solve them is through global co-operation," Prof Barnosky said.
"The big winners in the world 50 years from now will be the nations that have developed new forms of energy. Those nations and entrepreneurs are going to come out ahead."