Climate Warnings, Growing Louder

The news that atmospheric concentrations of carbon dioxide, the most important global warming gas, have hit 400 parts per million for the first time in millions of years increases the pressure on President Obama to deliver on his pledges to limit this country’s greenhouse gas emissions.
Read the editorial of nyt :
http://www.nytimes.com/2013/05/19/opinion/sunday/climate-warnings-growing-louder.html?hp&_r=0