In recent years, the U.S. debate on global warming policy has been stymied by the unachievable goals of the Kyoto Protocol. Cutting U.S. emissions by one-quarter in barely a decade, as agreed at Kyoto, was never politically feasible.

Now the Bush administration, nearly a year after pulling out of the Kyoto Protocol, has finally announced its own plan for global warming. It falls far short of a grand strategy but does take a few important steps forward.

One of them is to offer a better way to measure progress on the problem. The Bush plan sets goals in terms of "greenhouse gas intensity" -- the ratio of greenhouse gas emissions per unit of economic activity. That ratio declines as the economy grows and policies encourage people to control emissions of greenhouse gases. The administration seeks an 18 percent reduction in intensity over the next decade.

By contrast, the Kyoto approach would require the United States and all other industrialized nations to regulate their total quantity of emissions to exacting targets during brief five-year periods. Thus the Kyoto approach unwittingly pitted advocates of economic growth against those who sought environmental protection, especially in the United States. As the U.S. economy grew rapidly in the 1990s, emissions soared, and it became ever harder to devise an economic plan for meeting the Kyoto limits.

The truth is that policymakers are not able to plan compliance for Kyoto-style targets because they don't really have much control over the short-term volume of emissions. Governments can implement such policies as fuel economy standards or tax credits for carbon-free fuels, but these are most effective only over long time periods. By putting a spotlight on trends in greenhouse gas intensity over long periods of time, the new approach better matches goals with the real leverage available to policy- makers.

The administration's plan would also invest more in scientific research on the causes and dangers of global warming. And it wisely pumps new money into research on energy technologies, such as fuel cells, that may allow future generations to move beyond fossil fuels.

But the weaknesses in the plan are severe. First, it is exceedingly modest. The planned cut in greenhouse gas intensity -- less than 2 percent per year compounded over the next decade -- sounds like a lot, but viewed from the long perspective of economic history it is trivial. In the 19th century, U.S. greenhouse gas intensity rose as industrialization accelerated the burning of fossil fuels even more rapidly than the economy swelled. Greenhouse gas intensity peaked in 1917 and has been declining ever since, on average about 1.5 percent per year.

New economic activities -- such as banking and software design -- do not require the same level of emissions as old energy-intensive industries such as steel production.

The Bush plan does little to accelerate this decoupling of economic growth from greenhouse gas emissions. Even the planned cut in intensity will not stop the growth in total emissions, which will probably rise about 10 percent in the next decade.

The Europeans won't be impressed. Their greenhouse gas intensity is already one-third lower than the United States' and slated to decline more than 2 percent per year over the next decade.

A second weakness in the Bush plan is the lack of credible incentives for firms to invest in emission reductions. Clear signals are necessary because the power plants, cars and factories we build today will constrain our freedom to control emissions in the coming decades.

Rather, the plan only encourages firms to implement voluntary reductions in emissions. Firms that make cuts would earn credits that would be honored in the future, if the United States ever adopts a mandatory emission control scheme.

This voluntary system could accelerate development of a binding emission trading system for the United States, which would be a welcome step forward. In the interim, though, the voluntary approach will create a snake pit of promises and technical problems that will hamper serious future efforts to control emissions. For example, how will the U.S. government know whether a firm has reduced its emissions? A complicated and intrusive scheme to review every project might offer answers, but it would be costly and bureaucratic. Worse, this approach allows firms that happen to install technologies that reduce emissions to stake a claim on credits that would be tradable in the future. In essence, it encourages a land rush in which the dirtiest firms with the largest potential for emission reductions can seize the greatest property rights. A better approach would start with a simple, binding system today.

Third, the new plan fails to solve many of the problems that rightly led the Bush administration to criticize the Kyoto framework. Last spring the president lambasted Kyoto for setting arbitrary short-term targets. His plan is little different -- it sets vapid short-term goals, yet is silent on long-term trajectories that matter most.

Nor does the plan offer a credible reply to the administration's critique that Kyoto fails to require participation by developing countries. The administration's plan offers some additional funding to entice developing countries, but the sum total is actually much smaller than the schemes that other nations are already developing within the Kyoto framework.

The good news is that the administration has broken its silence on the important problem of global warming and offered a reasonable framework for debating policy goals. The bad news is that it offers little else.

The writer directs the Program on Energy and Sustainable Development at Stanford. He is a senior fellow at the Council on Foreign Relations and author of "The Collapse of the Kyoto Protocol and the Struggle to Slow Global Warming."