Greenhouse gases reached historic highs in 2013, a U.N. report says, in part because of rising emissions from automobiles and smokestacks. (Mark Ralston/AFP/Getty Images) Levels of heat-trapping carbon dioxide in the atmosphere rose at a record-shattering pace last year, a new report shows, a surge that surprised scientists and spurred fears of an accelerated warming of the planet in decades to come. Concentrations of nearly all the major greenhouse gases reached historic highs in 2013, reflecting ever-rising emissions from automobiles and smokestacks but also, scientists believe, a diminishing ability of the world’s oceans and plant life to soak up the excess carbon put into the atmosphere by humans, according to data released early Tuesday by the United Nations’ meteorological advisory body. The latest figures from the World Meteorological Organization’s monitoring network are considered particularly significant because they reflect not only the amount of carbon pumped into the air by […]