"Scientists monitoring global atmospheric carbon dioxide concentrations report that, for the first time in human history, CO2 levels could soon rise above 400 parts per million for a sustained period of time in much of the Northern Hemisphere."

"The latest round of international climate change talks commenced [Monday] with the now perennial warning about the need for greater urgency from governments as they battle to curb global greenhouse gas emissions."

"Environmental groups on Monday announced a new ad campaign that highlights ExxonMobil's massive oil spill in Arkansas last month. The ads will be concentrated in the Washington, D.C., Metro's Foggy Bottom station, which is used by many State Department employees commuting to work, as the agency considers whether to approve the construction of the Keystone XL pipeline."

"PITTSBURGH -- The Environmental Protection Agency has dramatically lowered its estimate of how much of a potent heat-trapping gas leaks during natural gas production, in a shift with major implications for a debate that has divided environmentalists: Does the recent boom in fracking help or hurt the fight against climate change?"

"The campaign group formed to support Barack Obama's political agenda has launched an initiative to shame members of Congress who deny the science behind climate change."

"HATCH, N.M. -- In southern New Mexico, the mighty Rio Grande has gone dry -- reduced to a sandy wash winding from this chile farming community to the nation's leading pecan-producing county. Only puddles remain, leaving gangs of carp to huddle together in a desperate effort to avoid the fate of thousands of freshwater clams, their shells empty and broken on the river bottom."

"The Environmental Protection Agency issued a sharply critical assessment of the State Department's recent environmental impact review of the controversial Keystone XL pipeline, certain to complicate efforts to win approval for the $7-billion project."

"CLEARWATER -- Despite warnings from scientists, rising sea levels still seem little more than a distant, imperceptible threat, a phenomenon whose change is measured in centimeters over decades."

"WASHINGTON -- A dozen states and cities and three major environmental groups have notified the Environmental Protection Agency that they plan to sue the regulator unless it issues final rules limiting greenhouse gas emissions from new power plants."

"WASHINGTON, DC -- Support for global action to curb climate change is growing stronger within the G8 group of the world’s largest industrial democracies, which includes the United States and Japan."

"LONDON -- The development of low-carbon energy is progressing too slowly to limit global warming, the International Energy Agency (IEA) said on Wednesday."

"MOSCOW — It was once protected by ice. Now regulation will have to do the work."

"After a generation of effort, New England's waters are clean enough to support an oyster industry. But climate change could undermine those gains."

The 2013 Pulitzer Prize for National Reporting went to InsideClimate News, a 5-year-old web-only nonprofit, for its book-length feature series on the 2010 Enbridge tar-sands oil spill that fouled miles of Michigan's Kalamazoo River. InsideClimate has been one of the most aggressive media outlets covering the current spill in Mayflower, Arkansas. ExxonMobil recently threatened one of InsideClimate's reporters with arrest for trying to find a federal government press office handling the spill.

"CANBERRA -- The summer ice melt in parts of Antarctica is at its highest level in 1,000 years, Australian and British researchers reported on Monday, adding new evidence of the impact of global warming on sensitive Antarctic glaciers and ice shelves."