World carbon emissions will essentially have to come to a halt by midcentury to avoid severe disruption of the earth's climate system, warn the 47 authors of the Worldwatch Institute's book, 'State of the World 2009: Into a Warming World.'
World carbon emissions will essentially have to come to a halt by midcentury to avoid severe disruption of the earth's climate system, warn the 47 authors of the Worldwatch Institute's book, .
Released Tuesday, the Washington, D.C., sustainability research group's 26th annual State of the World report says that the coming year will be crucial for the earth's climate. In December, world leaders will gather in Copenhagen, Denmark, to hammer out a successor to the Kyoto Protocol, which sought to curb greenhouse-gas emissions to prevent the earth from warming more than 3.6 degrees Fahrenheit above preindustrial levels. Scientists say the planet's average temperature has gone up 1.4 degrees F. since the mid 18th century.
But this threshold is probably too high, argues a chapter by climate scientist W.L. Hare. A 3.6 degree F. rise would probably lead to mass extinctions, famine, water shortages, and coastal flooding, writes Mr. Hare, an environmental scientist with the Potsdam Institute for Climate Impact Research and a lead author of the United Nation's climate panel's seminal 2007 report on global warming. Hare, who says that uncertainties about climate sensitivity make it impossible to define an unambiguously safe warming threshold, urges that we do everything we can to avoid a warming of more than 0.4 degrees above present levels.