Prime Minister David Cameron once dog-sledded across a shrinking Norwegian glacier to showcase his concern for global warming. Now, environmentalists say, his pledge to lead a new era of the "green Conservative" is in danger of melting away.

Cameron's troubled road on the environment illustrates the potential pitfalls ahead for any Republican leader who might try to emulate his grab for the political center. Even as he maintains a tough stance on fiscal discipline, Cameron has sought to appeal to moderates by supporting issues ranging from gay marriage to combating climate change. But he has paid with a series of political backlashes that have, at times, forced him to curtail his ambitions.

In few areas is that more true, environmentalists say, than on the issue of climate change. The latest blow, they say, came when Cameron recently called for a rollback of "green taxes" in British energy bills that help pay for, among other things, better insulation in low-income homes and subsidies for alternative energies. Cameron did not elaborate on his idea. But advocates described it as the latest setback on what he once promised would be the "greenest" government in British history.