Thursday, June 7, 2012
Human activity may be driving the earth's climate toward an irreversible tipping point, say researchers from the University of California and around the world. This could mean major changes to ecosystems we rely on for clean water, fisheries and agriculture.
About forty-three percent of Earth's land surface has been converted to agricultural or urban use. Scientists claim this and other human pressures on the climate mean we could see a major species extinctions and ecosystem changes within a few generations.
UC Berkeley paleontologist Tony Barnosky said at a minimum, the change would be as great as the last glacial transition - where about half the large mammals went extinct. He said we're putting substantial and unprecedented pressures on climate and ocean.
"All of those things are more intense than what happened during last time we saw one of these major global state shifts 11k-700 years ago, so pressures we're exerting are actually stronger than pressures exerted during last time this happened," explained Barnosky.
If the planet hits such a tipping point, he said it'd really be a new world biologically. And for California that grows over 200 crops, that could mean major shifts in what can be grown.