"The war of words between the Obama reelection campaign and billionaire conservative activists Charles and David Koch escalated Wednesday. The president's campaign manager, Jim Messina, sent a letter to Philip Ellender, Koch’s president for government and public affairs, disputing Ellender's claim that an organization partially backed by the brothers represented the interests of thousands of grassroots donors."

"The House approved a bill Wednesday that rewrites two decades of water law in California, wiping out environmental protections and dropping reforms of federal irrigation policy that have long irritated agribusiness in the Central Valley."

"Senate Energy and Natural Resources Committee Chairman Jeff Bingaman (D-N.M.) will introduce legislation Thursday mandating that power companies generate a major portion of the country’s electricity from low-carbon energy sources."

"An associate of the Heartland Institute, the thinktank devoted to discrediting climate change, taught a course at a top Canadian university that contained more than 140 false, biased and misleading claims about climate science, an expert audit has found."

"GRAND JUNCTION, Colo.—Chevron Corp. is giving up its experimental oil shale lease in northwest Colorado, saying it wants to free up its resources for other priorities."

"Move over, Solyndra. Conservatives opposed to the Obama administration's spending on clean energy have a new whipping boy.

The electric Chevrolet Volt is the new focus of angry conservative blog posts, testy congressional hearings and joking videos. And Republican presidential candidates Mitt Romney and Newt Gingrich have taken shots at the car's puny sales and size, with Gingrich jeering, 'You can't put a gun rack on a Volt.'

"Federal agencies [Monday] released environmental justice strategies, implementation plans and progress reports, outlining steps they will take to protect communities facing serious health and environmental risks, particularly low-income, minority and tribal populations."

"U.S. environmental regulators have proposed a new rule that limits requirements for factories to hold permits for greenhouse gas carbon emissions to the largest sources such as big coal-fired power plants and big manufacturers."

"If the importance and complexity of a court case can be established based on the number of lawyers at the lectern, then the battle over the Obama administration greenhouse gas regulations is of epic proportions. When the three interlinked cases are argued over two days at the U.S. Court of Appeals for the District of Columbia Circuit this week, no fewer than 18 different attorneys will advocate for their clients before the three-judge panel."

"TransCanada said Monday that it would reapply for a permit to build the Keystone XL pipeline from Canadian oil sands formations in Alberta to refineries on the Gulf of Mexico, assuring that the fiercely contested project will remain a source of political heat throughout the presidential campaign.