05/13/2013
CO2 Levels Reach Record High, Scientists Concerned
Earth’s atmosphere is entering an era that hasn’t been seen for millions of years, and the scientific community is worried. Scientists in Hawaii announced the level of carbon dioxide in the air has reached 400 parts per million. The last time the greenhouse gas reached this mark, horses and camels lived in the Arctic. Oceans were at least 30 feet higher -- a level that would flood major cities around the world.
■Class discussion: Why has the concentration of carbon dioxide risen so high? What does this mean for our future? Can mankind do anything to stop or limit greenhouse warming? What ideas have some scientists proposed to cope with the changing climate? What was the world like during the "Hothouse Earth" era the last time carbon dioxide levels were so high?