CO2 and greenhouse gas emissions reach a record level. In May 2013, carbon dioxide levels in the atmosphere exceeded 400 parts per million. This “approaches the halfway point between pre-industrial levels and the doubling of those levels” (Washington Post J). This is a very large increase in the amount of CO2 in our atmosphere over a short period of time. We may wonder what consequences the presence of such a large volume of CO2 floating in our atmosphere could have. The Union of Concerned Scientists states that CO2 is considered a greenhouse gas. Greenhouse gases are gases that trap radiant energy in the lower atmosphere. Energy travels from the sun to the Earth, which is then absorbed by the atmosphere and the ground. Energy that is not absorbed by the ground is reflected back into the atmosphere and then goes into space or is trapped by greenhouse gases. More thermal energy will be trapped if there are more greenhouse gases floating in the Earth's atmosphere (UCS). Due to the nature of greenhouse gases, the doubling of CO2 levels in our atmosphere is expected to cause four to seven degrees of warming this century. (Washington Post J). Current CO2 levels are worrying because if more heat were trapped in the atmosphere, Earth's climate would also be expected to increase. Global average temperatures have increased at an accelerating rate in recent decades. NASA's Goddard Institute for Space Studies has been analyzing and recording global average temperatures since 1880. NASA scientists say 2013 is tied with 2009 and 2006 as the 7th warmest year. The 10 warmest years in 134 years have occurred since 2000, with the exception of 1998 and 2010 and...... middle of paper ......Scientific credibility - in a pie chart. "Why Climate Denialists Don't Have Scientific Credibility - In a Pie Chart. DeSmogBlog, November 15, 2012. Web. February 14, 2014. (G)Rice, Doyle. "The Arctic Takes a Break in 2013, But Warming is still in progress. » Gannett News Service. 2013: np SIRS Issues Researcher. February 7, 2014. (E) Sobel, Adam and the opinions expressed in this commentary are solely those of Adam Sobel. not global warming." Network, January 7, 2014. Web. February 20, 2014. (B) Spotts, Pete. “Climate change: Scientists are now 95% certain that most of us are…” Christian Science Monitor August 20 2013: np Sirs Issues Reseracher Web. February 13, 2014. “Why does CO2 get the most attention when there are so many other heat-trapping gases” Union of Concerned Scientists Union of Concerned Scientists? , May 1, 2009. Web.. 2014.