By introducing a tax on carbon dioxide emissions in conjunction with other related measures, the economic burden of efforts to curb global warming could be minimized, according to an Environment Agency report released earlier this week.

The report details the results of the first set of simulations comparing the efficiency of a variety of schemes aimed at reaching a uniform result -- a 2 percent reduction in greenhouse gases by 2010 based on 1990 levels. This represents the agency's most detailed attempt at outlining various schemes.

The simulations indicated that various means of reducing emissions exist and will likely prompt expanded debate as the agency grapples to find a satisfactory emissions reduction plan.

The simulations showed that simply introducing a carbon emissions tax would impair the nation's gross domestic product in 2010 by 0.68 percent compared with what would otherwise have been the case.

On the other hand, a mixture of policies, including promoting carbon dioxide emissions trading and the wise use of carbon tax revenues, could lower the contraction to around 0.24 percent.

"Through a combination of policies -- such as taxes and emissions trading, and taxes and investment in energy-saving subsidies -- it is possible to achieve nearly the same level of . . . emissions reductions," the paper says.

A straight carbon tax would cost around 30,000 yen to 40,000 yen per ton of carbon dioxide, equivalent to 1,555 liters of gasoline, the report says.

This would translate to up to 26 yen per liter more for consumers at the pumps, whereas a simulation indicated that a wisely concocted combination of steps could greatly lower the burden, possibly to as low as 1 yen per liter.

The paper, for the first time, states that the efficient use of revenues from a carbon tax -- such as for subsidies that reward energy efficiency -- could greatly mitigate the economic impact of greenhouse gas reduction efforts.

The report adds that a shift from regulatory steps to market-based incentives is visible overseas, noting that major European countries are set to introduce taxes as a tool to combat the emission of greenhouse gases and that the U.S. and Canada are preparing to establish carbon trading.

Agency officials said that further deliberation will determine which blend of policies are the most viable, and the outcome of the deliberations will likely be reflected in the revised Basic Environment Plan when it is presented later this year.

Agency officials said the earliest a carbon tax and coordinated reduction scheme would debut would be 2002.