350 ppm

In the article “A Last Chance to Advert Disaster,” Dr. James E. Hansen talks about the dangers of climate change.  Hansen explains how greenhouse gasses are responsible for the climate change and that humans have caused it to occur.  This change has led to the alteration of the water cycle, causing more droughts, heavier rains, and more floods.  Even with all of this data collected, many people do not see the seriousness of the issue.  The United States has declined putting limits on carbon emissions, and other developing countries have increased their emission rates.  The possible consequences which could occur if the earth is allowed to rise even two degrees fahrenheit in temperature are also described.  Glaciers could melt completely, causing a two meter rise in sea level.  In addition, the extinction of all polar species would be put at risk due to this. 

Currently the earth is made up of 385 ppm of carbon dioxide and rising 2 ppm a year.  Earth is not sustainable unless a level of 350 or less ppm is reached.  There is not much time for the earth to reach this goal however.  “A level of no more than 350 ppm is still feasible, with the help of reforestation and improved agricultural practices, but just barely – time is running out.”  To solve this problem, Hansen believes coal should no longer be used.  It is necessary for the world to transfer over to carbon-free energy for cars, instead of fossil fuels.  This would cause less carbon dioxide to be released in the atmosphere, allowing the level of carbon dioxide to decrease.  Hansen also believes that a tax should be put on carbon, so people are less inclined to use it.  Lastly, the author says it is critical for our political leaders to believe this change is necessary too.