Scientists Describe Evidence of Impending Tipping Point for Earth

by Duane Nichols on June 17, 2012

Scientists from around the world are warning that population growth, widespread destruction of natural ecosystems, and climate change may be driving Earth toward irreversible change. This planet-wide tipping point would have destructive consequences unless adequate preparations and programs for change are instituted.

UC Berkeley professor Tony Barnosky tells how an increasing human population, coupled with climate change, could irreversibly alter Earth’s ecosystem in a video produced by Roxanne Makasdjian.

“It really will be a new world, biologically, at that point,” warns Anthony Barnosky, professor of integrative biology at the University of California, Berkeley, and lead author of the review paper appearing in the June 7 issue of the journal Nature. “The data suggests that there will be a reduction in biodiversity and severe impacts on much of what we depend on to sustain our quality of life, including, for example, fisheries, agriculture, forest products and clean water. This could happen within just a few generations.”

The Nature paper, in which the scientists compare the biological impact of past incidences of global change with processes under way today and assess evidence for what the future holds, appears in an issue devoted to the environment in advance of the June 20-22 United Nations Rio+20 Earth Summit in Rio de Janeiro, Brazil.

The result of such a major shift in the biosphere would be mixed, Barnosky noted, with some plant and animal species disappearing, new mixes of remaining species, and major disruptions in terms of which agricultural crops can grow where.

This work by 22 internationally known scientists describes an urgent need for better predictive models that are based on a detailed understanding of how the biosphere reacted in the distant past to rapidly changing conditions, including climate and human population growth.

In a related development, groundbreaking research to develop the reliable, detailed biological forecasts the paper is calling for is now underway at UC Berkeley. The endeavor, The Berkeley Initiative in Global Change Biology, or BiGCB, is a massive undertaking involving more than 100 UC Berkeley scientists from an extraordinary range of disciplines that already has received funding.

Currently, to support a population of 7 billion people, about 43 percent of Earth’s land surface has been converted to agricultural or urban use, with roads cutting through much of the remainder. The population is expected to rise to 9 billion by 2045; at that rate, current trends suggest that half Earth’s land surface will be disturbed by 2025. To Barnosky, this is disturbingly close to a global tipping point.

“My view is that humanity is at a crossroads now, where we have to make an active choice,” Barnosky said. “One choice is to acknowledge these issues and potential consequences and try to guide the future (in a way we want to). The other choice is just to throw up our hands and say, ‘Let’s just go on as usual and see what happens.’ My guess is, if we take that latter choice, yes, humanity is going to survive, but we are going to see some effects that will seriously degrade the quality of life for our children and grandchildren.”

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