Associated Press: Carbon dioxide levels in the atmosphere reached a record high in 2013 as increasing levels of man-made pollution transform the planet, the U.N. weather agency said Tuesday.
In an annual report, the World Meteorological Organization said that carbon dioxide, the heat-trapping gas blamed for the largest share of global warming, rose to global concentrations of 396 parts per million last year, the biggest year-to-year change in three decades.
That's an increase of 2.9 ppm from the previous year...