There is a growing possibility that the U.S. will pass no climate change legislation in this session of Congress: the uphill climb is at least as steep, and probably steeper, as it is for health care legislation. President Barack Obama cannot presume to hold his own party in line on climate change. Several Democratic senators have already asked him to stop pushing for a bill in 2010, given the proximity to the midterm elections.

The fracture lines are countless, but probably the most important one runs through public opinion. A recent poll showed only 36 percent of Americans believing that the evidence of human-induced climate change is firm, down from 47 percent in early 2008. The rise of unemployment has perhaps made people more reluctant to accept adverse news on living standards. There is also considerable public confusion about climate science and possible remedies.

Vested interests, especially coal and oil, play their predictable role. Half the states produce at least some coal, and around 30 states produce at least a bit of oil. In the dozen or so major coal or oil states, opposition to climate change action is politically powerful and well organized. Oil-producing states in the Gulf of Mexico tend to resist climate action even though the Gulf is probably already experiencing damage from rising hurricane intensity.

The environmental community is also divided. Many environmental groups oppose nuclear power and any use of coal, even with carbon capture and sequestration technology. Conservationists have fought many renewable energy projects, opposing wind power near farms and coastlines, solar thermal plants in the desert and high-voltage transmission lines near residential communities.

Another factor is the bargaining approach to climate legislation. Rather than defining a plan toward a low-carbon economy, the White House has left the negotiations to Congress and the lobbyists. The result is sprawling draft legislation, hard for the public to understand and replete with hidden and overt financial transfers to vested interests, especially in the allocation of emissions rights under a complex cap-and-trade system.

Perhaps the legislation can still narrowly pass, which at this point would be the best option. If it stalls this spring, however, the climate and the rest of the world can’t wait. A different approach is needed. Here are some components.

First, the Environmental Protection Agency has the mandate to move under the Clean Air Act. It could impose a timetable of emissions standards for electric utilities and for vehicles, which together account for around three fourths of carbon emissions. There is also broad support for needed R&D funds and important scope for energy efficiency through weatherproofing and green building codes.

Second, if cap-and-trade stalls, the administration and Congress should rethink their opposition to the much simpler option of a carbon tax. A predictable carbon tax would be much more effective than the cumbersome and nontransparent cap-and-trade system and might win broader assent as part of a package of deficit reduction.

Third, the public needs to hear a plan. The administration has embraced a goal of 17 percent reduction of greenhouse gas emissions by 2020, but it hasn’t told us how that would be achieved. The public is scared that even this modest goal would slam jobs and living standards. It’s time to spell out the changes in power generation, automobile technology and energy efficiency that can take us to our goals at modest cost and huge social benefit.

Fourth, it’s time to step up the response to the climate skeptics, who have misled the public. The Wall Street Journal leads the campaign against climate science, writing editorials charging that scientists are engaged in a massive conspiracy. I have made repeated invitations to the Journal editors to meet with climate scientists publicly for an open discussion or debate, but all have been rebuffed.

Let’s hear more from the president’s science adviser, John P. Holdren, Nobel laureate energy secretary Steven Chu, the National Academy of Sciences and other authorities. The public will learn to appreciate that the scientific community is working urgently, rigorously and ingeniously to better understand the complex climate system, for our shared safety and well-being.