The majority of Americans would choose more fuel-efficient vehicles if they were widely available — and the same holds true for cleaner fuels. Those are the conclusions of major public opinion surveys published by the Pew Research Center and UPI/Zogby International.

But the reality is that most of the sedans, trucks and sport utility vehicles available for purchase today are not built to optimize fuel economy and reduce carbon emissions. And it’s all but impossible to find fuels that emit less carbon dioxide than traditional gasoline, such as biodiesel, E-85 or hydrogen, at a local fueling station.

The simple truth is that we no longer can afford to delay. The world’s leading climate change experts have concluded that catastrophic global warming is just around the corner, unless we take dramatic steps to change our habits.

So what can be done?

First, we should raise the Corporate Average Fuel Economy standards for all cars, trucks and SUVs.

Second, we need to increase the supply of cleaner fuels and require improvements to vehicular technology to reduce tailpipe emissions.

With more than 240 million motor vehicles in use today — spewing 20 pounds of carbon dioxide emissions into the atmosphere with every gallon of gasoline burned — this one sector produces more than 2 billion metric tons of carbon dioxide every year, or roughly one-third of total U.S. greenhouse gas emissions. And the use of automobiles alone produces about 25 percent of all U.S. emissions.

So the transportation sector is a good place to start.

That’s why Sen.Olympia Snowe (R-Maine) and I have joined with a bipartisan coalition of Senators, including Daniel Inouye (D-Hawaii), Dick Durbin (D-Ill.), John Kerry (D-Mass.), Barbara Boxer (D-Calif.), Bill Nelson (D-Fla.), Maria Cantwell (D-Wash.), Frank Lautenberg (D-N.J.), Joe Lieberman (ID-Conn.), Bob Menendez (D-N.J.), Susan Collins (R-Maine), Jack Reed (D-R.I.), Patrick Leahy (D-Vt.), Bernie Sanders (I-Vt.), Chris Dodd (D-Conn.) and Daniel Akaka (D-Hawaii), to push for legislation that would require automakers to build a cleaner fleet.

Specifically, the Ten-in-Ten Fuel Economy Act (S. 357) would raise CAFE standards for all new U.S. sedans, light trucks and SUVs from 25 miles per gallon to 35 mpg by model year 2019.

This critical step would:

• Reduce U.S. transportation emissions by 18 percent below projected levels by 2025, which is the equivalent of taking 60 million of today’s cars off the road in one year; and

• Save 2.1 million barrels of oil per day by 2025, which is nearly the amount of oil we currently import from the Persian Gulf.

The National Academy of Sciences tells us these improvements can be achieved using existing technologies — and they won’t affect performance or safety.

So this bill offers a common-sense, cost-effective approach to improve fuel economy. Congress must find the political will to pass it.

We also must target emissions that come from the use of motor vehicles.

The combustion of traditional gasoline is the primary cause of emissions in the transportation sector. And the use of motor vehicles consumes 185 billion gallons of gasoline annually.

So I’ve joined with Sens. Collins and Snowe to introduce legislation to reduce the carbon content of the fuels on which they run and improve technologies that reduce tailpipe emissions.

By 2016, the Clean Fuels and Vehicles Act of 2007 (S. 1073) would mandate the auto industry to reduce tailpipe emissions from new vehicles by 30 percent below 2002 levels. This would apply California’s landmark tailpipe emissions reduction standard nationwide.

Automakers could cut tailpipe emissions through the development of better engines, transmissions, aerodynamics and air conditioning systems, as well as through the production of vehicles that can run on low-carbon fuels.

The bill also would require fuel suppliers to increase the percentage of low-carbon fuels — biodiesel, E-85, hydrogen, electricity and others — in the motor vehicle fuel supply. Having these cleaner alternatives to traditional gasoline would reduce emissions from the use of motor vehicles by 10 percent below projected levels by 2030.

By 2030, this bill would:

• Reduce greenhouse gas emissions from the use of motor vehicles by 22 percent below projected levels;

• Prevent 662 million metric tons of carbon dioxide from being produced, the equivalent of taking 96 million of today’s automobiles off the road in one year; and

• Reduce U.S. oil consumption by 3.6 million barrels of oil per day or roughly one and a half times the amount of oil imported from the Persian Gulf today.

So this would be a major step in the right direction.

But this is not all we can do.

We also must slash harmful greenhouse gas emissions across the board. And I believe our best bet is a sector-by-sector approach. This would include cap-and-trade programs for the electricity and industrial sectors as well as energy-efficiency incentives for homes, businesses and industries.

So I urge my colleagues to join with me in this fight — and get serious about global warming.

Let’s begin by building a cleaner fleet and increasing the supply of low-carbon fuels to power our vehicles.

Global warming cannot be stopped, but it can be slowed. The time for action is now.

Sen. Dianne Feinstein (D-Calif.) is chairwoman of the Rules and Administration Committee and the Appropriations subcommittee on Interior, Environment and related agencies.