Climate Change Verdict: Science Debate Concludes, Solution Debate Begins
sduford on Feb 08 2007 at 6:27 pm | Filed under: Global Warming, The Science
The IPCC summary for policymakers definitively proclaimed the globe to be warming as a result of human activity, now the science shifts to impacts and solutions
By David Biello, Scientific American
The debate over whether the Earth’s climate is changing and whether humanity is responsible for that change closed in Paris on February 2. The Intergovernmental Panel on Climate Change (IPCC) released its summary for policymakers–a summation of the salient science in its much-longer report due in May–in which it said that climate change is “unequivocal” and estimated the chances of humans being behind it at 90 percent–”very likely.”
New observations and new models contributed to this certainty, ranging from Antarctic ice cores to improved understanding of solar fluxes. Carbon dioxide (CO2) levels in the atmosphere–379 parts-per-million (ppm) in 2005–have reached levels not seen in the last 650,000 years, which have varied between 180 ppm and 300 ppm. The burning of fossil fuels is the main CO2 contributor to the atmosphere, followed by clearing land for agriculture.