Billionaire climate activist Tom Steyer, who's increasingly throwing his weight around in politics, said approving the Keystone XL oil sands pipeline would create political hurdles for President Obama’s second-term agenda and cost him the support of key donors.

Steyer, a major Democratic fundraiser, told Grist magazine that Keystone opponents have leverage to exert over Obama even though he’s free of having to run for reelection.

“If you look at the people who support Obama, and then you look at the people who support him actively and give money, the number of people who care about climate in this second group is actually a majority — not out of the people who support him, but the people who are really active and give money. It's an enormously high percentage," Steyer, who made his fortune running a hedge fund, said in the wide-ranging interview.

Steyer cautioned that Obama should be careful not to alienate these influential supporters.

The Obama administration on Thursday unveiled a new proposal for its first major regulation of hydraulic fracturing on public lands, attempting to address at least a portion of the controversial drilling practice that's unlocked vast new supplies of U.S. oil and gas but has also raised fears about its environmental impact, particularly on local water supplies.

The proposal is softer on energy producers than an initial draft floated by the Interior Department’s Bureau of Land Management last year. Over the past several months, oil and gas executives—including lobbyists for ExxonMobil, Halliburton, and the American Petroleum Institute—have met several times with administration officials, asking them to loosen the rule.

Environmentalists immediately slammed the proposal, saying that it gives far too many concessions to the industry and won’t protect communities from possible contamination of water tables.

"These rules protect industry, not people. They are riddled with gaping holes that endanger clean, safe drinking water supplies for millions of Americans nationwide," said Frances Beinecke, president of the Natural Resources Defense Council. 

After boycotting the same confirmation vote a week earlier, Republican senators agreed Thursday to show up for a committee vote on President Barack Obama’s pick to be the nation’s top air and water quality regulator.

The Senate Environment and Public Works Committee voted 10-8 to move along Gina McCarthy’s nomination as administrator of the Environmental Protection Agency to the full Senate for a vote.

Republicans, led by Louisiana Sen. David Vitter, held up the committee vote for several weeks, saying the EPA hadn’t adequately answered questions about McCarthy’s role as a deputy there. Vitter asked McCarthy a record-breaking 653 questions, out of 1,120 from the committee.

The owner of a crude oil pipeline that runs between Maine and Montreal is asking Vermont environmental regulators to reconsider a ruling that would require a new review under the state's land-use planning law if the company seeks to move Canadian tar sands oil to Portland for possible shipment to markets across the world.

In its motion to reconsider, the Portland-Montreal Pipeline Corp. Pipeline said the coordinator of the District 7 Environmental Commission, who issued the ruling last month, got the facts wrong that she used to reach her conclusion that any effort to reverse the flow would represent a significant change that would require it to be reviewed by the state's land use development law, Act. 250.