Climate Change & Global Warming

The annual average concentration of carbon dioxide (CO2) in the atmosphere stood at 395.3 parts per million (ppm) in 2013—a 27 percent increase compared to conditions before the Industrial Revolution. On May 9, 2013, the daily average concentration of CO2 surpassed 400 ppm for the first time at the Mauna Loa Observatory in Hawaii.

March 2012

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    It is virtually certain our world will continue to warm over this century and beyond. The exact amount of warming that will occur in the coming century depends largely on the energy choices that we make now and in the next few decades.