The earth’s atmosphere hasn’t held this much CO2 since the Pliocene Epoch, an ancient era that ended more than 2 million years before the first Homo sapiens appeared. Global CO2 levels hovered between 170 ppm and 300 ppm for ages until the Industrial Revolution, when a steady ascent began. The U.N. Intergovernmental Panel on Climate Change estimates 450 ppm is when the worst effects of climate change will begin.
Graphic courtesy NOAA
Dr. James E. Hansen says we must change energy policy to provide every citizen affordable access to clean energy – we are morally obligated to our children and grandchildren to do so.
Photo courtesy http://www.ted.com/talks/james_hansen_why_i_must_speak_out_about_climate_change.html
NASA’s Dr. James E. Hansen says, “The most exciting planetary research involves trying to understand the climate change on earth that will result from anthropogenic changes of the atmospheric composition.”
Photo courtesy http://www.guardian.co.uk/environment/2009/jan/01/scentist-letter-hansen-barack-obama