The carbon tax was a popular idea in the early 1990s when climate change was first coming to the fore as an environmental issue. Countries such as Sweden and Denmark introduced taxes on industrial emissions as well as some consumer items, such as gasoline.

Other countries, such as Britain, followed suit in the 21st century, although the experience of New Zealand might be more common. A carbon tax was proposed there and later withdrawn by the government in 2005.

The idea is being debated in countries such as Canada and Japan, but action — at least in North America — has been taken in recent months on a more regional level. Quebec implemented a modest tax on petroleum producers in 2007, while British Columbia is set to introduce its broad-based carbon tax on July 1.

Even municipalities, such as Boulder, Colo., and the San Francisco area have gotten in on the act. Boulder charges a consumer tax on electricity while the Bay Area tax targets industrial polluters.