House opponents of U.S. EPA's plans to regulate greenhouse gas emissions have become more sophisticated since February, when the House passed a rider to defund the climate program as part of a bill to temporarily fund the federal government, environmentalists said today.

This can be seen, they said, in changes made to a policy rider Interior and Environment Appropriations Subcommittee Chairman Mike Simpson (R-Idaho) has included in his committee's fiscal 2012 spending bill, which not only would prohibit the use of funds to formulate or implement greenhouse gas rules for stationary sources but would temporarily amend the Clean Air Act to remove EPA's obligation to do so.

The language the House passed in February as part of a stopgap spending bill would have prohibited the use of funds only, leaving the Clean Air Act unamended.

"It's not surprising they would have fixed that," said John Coequyt, the Sierra Club's senior climate and energy representative, who said the language in the House-passed continuing resolution was "extremely problematic" and would have effectively required some facilities to operate without a valid permit.

"It was obvious that that was an unworkable solution," he added. "No one was trying to come to a workable solution, because it was a political statement that the House was making."

John Walke of the Natural Resources Defense Council, in a call with reporters this morning, said that he could not see any potential for unintended consequences with the current language, which removes not only the funding for the greenhouse gas stationary source program in fiscal 2012 but also the legal basis for it.

"I think the drafters learned some lessons there, because they appear to do a pretty emphatically destructive job of abolishing EPA's authority," he said.

The House-passed continuing resolution would have placed utilities and other entities in certain states in an untenable position, environmentalists said, making it impossible for them to get valid permits that cover greenhouse gas emissions for the duration of the bill, but not removing the requirement that they have such a permit in order to operate. The language was jettisoned from the final version of the bill, which became law in April.

The language in the fiscal 2012 bill, by contrast, specifies among other things that "any Federal statutory or regulatory provision requiring a permit (or permit condition) under the Clean Air Act for emissions of greenhouse gases from a stationary source to address climate change shall be of no legal effect."

While the fiscal 2012 language would not create the de facto moratorium on permitting that environmentalists warned could follow the continuing resolution, Coequyt said it was still not a serious attempt to legislate, because the Senate and White House are unlikely to agree to it.

"I think it's really hard to make the case that this requirement is in any way impacting the economy," he said.

The House Appropriations Committee will mark up the spending bill tomorrow, and the full House could consider it as soon as this week.