Concerns are rising in California about a climate change mechanism known as carbon offsets -- similar concerns, in fact, to those now being felt in B.C.

California is moving to enact what is arguably one of the world's most comprehensive greenhouse gas reductions programs, known as A.B. 32.

The Golden State's cap-and-trade legislation, under that program, includes a mechanism where polluters can meet up to 8 percent of their emissions targets without actually shrinking their carbon footprint.

How do they do it? By investing in projects, such as reforestation schemes, that lower greenhouse gases.

But some observers are already questioning the system, worrying for example, about a forest owner who sets aside trees for preservation that he or she would have never cut down in the first place.

"If we cannot ensure with a high degree of confidence that the offset credits are real," Brian Nowicki, California climate policy director for the Center for Biological Diversity told Greenwire, "then this calls into question whether we are really achieving these reductions and thereby undermines the integrity of the cap-and-trade program as a whole."

As The Tyee reported last week, B.C.'s own carbon offset program is facing similar challenges.

The province is aiming to make every government building carbon neutral, a goal achieved by having institutions such as schools and hospitals buy carbon credits from a crown corporation called the Pacific Carbon Trust.

Critics claim that these institutions are being overcharged, and that the credits they purchase, especially for certain projects, amount to little more than hypothetical greenhouse gas reductions.

"And we're talking money from kids and patients to make this happen?" asked Bob Simpson, Independent MLA for Cariboo North.

Across the Pacific Ocean, Australia is struggling with public "fears" over its own climate change initiative, a carbon tax for corporate polluters.

"The government is going to stick to its guns," Australian Climate Change minister Greg Combet told Bloomberg. "We will continue to explain this to people."

Geoff Dembicki reports on energy and climate change issues for the Tyee and others.