"Amid the shouting on Capitol Hill, the wads of campaign cash and the activist careers shaped around the Keystone XL pipeline, the project at the flash point of America's energy debate now confronts a problem bigger than politics. It may no longer pencil out."

"Hotter days mean less cold cash for Americans, according to a new study matching 40 years of temperatures to economics."

"HOUSTON — The price of crude oil continued to collapse on Monday, plunging to a five-year low, as oil giants began to scale back their drilling ambitions and pare the ranks of their workers."

"Some of the best-known chefs in the country are leaving the kitchen this week and heading to Capitol Hill to press for mandatory labels on genetically modified food."

"President Vladimir V. Putin said Monday that he would scrap Russia’s South Stream gas pipeline, a grandiose project that was once intended to establish the country’s dominance in southeastern Europe but instead fell victim to Russia’s increasingly toxic relationship with the West."

"Falling oil prices show the 'high risk' of fossil fuel investments compared with renewable energies, the U.N.'s climate chief said on Monday at the start of 190-nation talks on a deal to slow global warming."

"VIENNA — The oil cartel OPEC decided on Thursday not to cut petroleum production, despite the plunge in prices in recent months that has indicated the diminishing clout of the organization."