Global Climate Change: A Warmer and More Unpredictable Future

Abstract

On May 9, 2013, the earth’s climate system reached a notable milestone. The concentration of carbon dioxide, or CO2, at the Mauna Loa Observatory in Hawaii passed 400 parts per million (ppm) when averaged over a whole day. This is the first time in more than 3 million years that the concentration has been this high. The CO2 concentration has increased by 40 % since 1890 when levels were about 280 ppm, an unprecedented rate of increase. Over the past million years, CO2 ranged between about 170 and 300 ppm as ice ages waned and waxed. According to Professor Clive Hamilton of Charles Sturt University in Canberra, Australia, “if you are not frightened by this fact,” and it is a fact, “then you are ignoring or denying science.” The rapidly increasing CO2 is a harbinger of dramatic climate changes to come in this century. But nowhere are these changes going to be felt more dramatically than in the American Southwest and along the coasts of the country.