"Stephen Harper heads to the White House on Wednesday to unveil a long-awaited border security agreement with U.S. President Barack Obama, but the visit comes at a particularly tense moment in Canada-U.S. relations as TransCanada's Keystone XL pipeline saga rages on."

GOP presidential candidate Jon Huntsman told conservatives Tuesday that he had doubts about the consensus science on manmade climate change -- science he once believed in. He is only the latest GOPer to flip-flop on science. There was a time when Republicans "believed" in science and cap-and-trade was a Republican invention.

"BEAVER, W.Va. -- Federal regulators on Tuesday blamed the Upper Big Branch Mine Disaster on "a workplace culture that valued production over safety," and prosecutors said a record $200 million settlement could set the stage for broad industry reforms."

"Those who fled Futaba are among the nearly 90,000 people evacuated from a 12-mile zone around the Fukushima Daiichi plant and another area to the northwest contaminated when a plume from the plant scattered radioactive cesium and iodine. Now, Japan is drawing up plans for a cleanup that is both monumental and unprecedented, in the hopes that those displaced can go home."

"DURBAN, South Africa -- The world's three biggest polluters China, the United States and India refused to move toward a new legal commitment to curb their carbon emissions Tuesday, increasing the risk that climate talks will fail to clinch a meaningful deal this week."

"DENVER -- Colorado regulators decided Monday night to wait a week before they start deliberating a proposal to require oil and gas companies to publicly disclose what chemicals they use in hydraulic fracturing."

"The federal government's strict new rules on mercury emissions are a pro-life issue that Christians should embrace to protect unborn children, according to a group of Christian environmentalists."

"Department of Agriculture researchers are working with rare plant pathogens that have the power to wipe out food crops that feed billions of people, or if harnessed and applied precisely, could control noxious weeds that have infested millions of acres of land."

"The Scripps Institution of Oceanography will present fresh evidence during a science conference in San Francisco Tuesday that pollution from central Asia affects the intensity of winter storms in California's Sierra Nevada, which provides a portion of the water consumed in San Diego County."