Despite an ever-tightening fiscal climate, the Obama administration and Congress should maintain investments in public lands, wildlife, clean air, water and renewable energy projects that reduce greenhouse gas emissions, dozens of environmental groups said today.

The groups' annual "Green Budget 2013" report outlines an array of investment priorities ranging from the obliteration of Forest Service roads to increased funding for research on a fungus that has killed some 6 million bats.

The 260-page report also recommends repealing billion of dollars in energy industry tax subsidies, a proposal pitched in the Obama administration's last budget request but one that is unlikely to gain political traction in an election year.

The report comes days before the White House is set to release its fiscal 2013 budget request and weeks before Congress must negotiate the expiring payroll tax cut.

"It's critically important to continue investing wisely in conservation, environmental protection and clean energy programs," said Scott Slesinger, legislative director for the Natural Resources Defense Council, which co-led the report with the Wilderness Society, Defenders of Wildlife, American Rivers, the National Parks Conservation Association, the Marine Conservation Institute and the National Audubon Society.

While federal spending on land, water, ocean and wildlife programs accounted for 1.26 percent of the federal budget in fiscal 2010, Congress' failure to identify a long-term deficit-reduction plan could lead to nearly 10 percent across-the-board funding cuts for those agencies beginning in January 2013, the report warns.

Although federal funding is tight, investments in clean air, water and land protections will substantially reduce future costs -- including health care and water treatment, among other benefits -- the report says. In many cases, conservation and clean energy programs will create jobs through activities like forest thinning, road decommissioning, and renewable energy research and development, it said.

"Conservation programs provide some of the greatest return on investment," said Alan Rowsome, director of conservation funding for the Wilderness Society, which urged support for land acquisitions, collaborative forest restoration projects and the Bureau of Land Management's National Landscape Conservation System.

"The cost of these programs is a small portion of the federal budget and thus a very small percentage of the average American family's tax expenditures, yet the benefits are extraordinary," the report says.

The report also urges Congress to abandon policy riders that have stirred fierce floor battles and delayed the appropriations process in the past.

While riders to restrict U.S. EPA's ability to regulate air and water pollutants have been dropped from recent appropriations battles, many other smaller provisions have survived, including measures to transfer air pollution oversight in the Arctic, eliminate endangered species protections and block a legal ruling that limited runoff from Forest Service roads.

"This hijacking of the appropriations process must cease so that policy issues can be debated and voted on in their proper forum, allowing equally important budget decisions to be made on their own merits," the report says.

The report also fights back against industry claims that EPA rules have made the United States less competitive and have increased unemployment. It says that although a recent review found agency actions have cost more than $7 billion dollars over the past decade, the benefits of those actions were between three and 24 times the cost, mostly in health benefits.

The report also recommends the repeal of an array of energy industry tax incentives, including tens of billions of dollars in oil industry subsidies and new hard-rock mineral royalties. It also recommends funding cuts for research into nuclear reactors and the evaluation of a shuttered nuclear fuel repository at Yucca Mountain, Nev.

The repeal is unlikely to sit well with the oil and gas industry, which came out swinging after President Obama proposed the tax incentive cuts in last year's budget.

American Petroleum Institute President Jack Gerard last year warned that Obama's budget proposal included almost $90 billion in tax increases on the oil and natural gas industry.

"Studies have shown that these tax increases would discourage oil and natural gas production, lead to fewer well-paying American jobs, increase our reliance on foreign imports and potentially contribute to higher energy costs to consumers," the group said in a statement.

Rowsome, of the Wilderness Society, said the Budget Control Act passed last summer and pending cuts for fiscal 2013 could significantly hamper the president's conservation agenda.

He said funding levels for conservation programs will likely remain flat this year compared to the fiscal 2012 request, with continued investment in a few high-priority areas.

"If it's going to align with the spending caps in place this year, the total pot of discretionary dollars has only inched up slightly," he said. "That gives you a lot less room to highlight important conservation show priorities."