Are corn husks better than corn for producing energy? Ethanol is the alternative fuel that could finally wean the U.S. from its expensive oil habit and in turn prevent the millions of tons of carbon emissions that go with it. The Department of Energy has doubled its 2005 commitment to funding research into biofuels—any non-petroleum fuel source, including corn, soybean, switchgrass, municipal waste and (ick) used cooking oil. Already, half of the nearly 11 billion bushels of corn produced each year is turned into ethanol, and most new cars are capable of running on E10 (10% ethanol and 90% gas).

Reducing your impact on the earth is not just a question of what you drive but also of what you live in. Residential energy use accounts for 16% of greenhouse-gas emissions. If you begin thinking green at the blueprint stage, however, low-tech, pragmatic techniques will maximize your new home's efficiency. Installing those systems from the ground up is cheaper than retrofitting. "Doing simple things could drastically reduce your energy costs, by 40%," says Oru Bose, a sustainable-design architect in Santa Fe, N.M.

The hottest thing in household energy savings is the compact fluorescent lightbulb (CFL), a funny-looking swirl that fits into standard sockets. CFLs cost three to five times as much as conventional incandescent bulbs yet use one-quarter the electricity and last several years longer. They are available virtually everywhere lightbulbs are sold. Most labels don't say "CFL" (GE calls its bulbs Energy Savers), and in some cases the telltale twist is enclosed in frosted glass. The wattage gives them away: many 7-watt CFLs are comparable to a regular 40-watt bulb, 26 watts is the typical CFL equivalent of 100 watts and so on. Or just look for the Energy Star label.

Cities can save energy—and money—by illuminating public spaces with LEDs, or light-emitting diodes. Last December Raleigh, N.C., turned one floor of a municipal parking garage into a testing ground for LEDs (see the before-and-after photos at cree.com/LEDcity). The new white, brighter fixtures use 40% less electricity than the high-pressure sodium bulbs they replaced. Although they cost two to three times as much, they can go five or more years without upkeep. Traditional bulbs must be replaced every 18 months. Other types of LEDs are already at work in traffic lights, outdoor displays (like those in New York City's Times Square) and stadiums; airports even use LEDs on their taxiways. If your city is still burning tax money on old lights, ask the mayor why.

Everyone agrees that it's necessary to reduce carbon emissions around the world. There is less agreement over exactly how nations should go about achieving a more carbon-free planet. Hence, the environmental equivalent of Elvis vs. the Beatles: cap-and-trade carbon emissions, or impose a carbon tax on all users? With cap-and-trade programs, governments limit the level of carbon that can be emitted by an industry. Companies that hold their emissions below the cap can sell their remaining allowance on a carbon market, while companies that exceed their limit must purchase credits on that market. Carbon taxes are more straightforward: a set tax rate is placed on the consumption of carbon in any form—fossil-fuel electricity, gasoline—with the idea that raising the price will encourage industries and individuals to consume less. At the moment, cap-and-trade has the upper hand, since it serves as the backbone of the current Kyoto Protocol, and helped the U.S. reduce acid rain in the 1990s—but don't write off the tax just yet.

Oversize houses aren't just architecturally offensive; they also generally require more energy to heat and cool than smaller ones, even with efficient appliances. And in the U.S., big houses are becoming the norm, even though a relatively inefficient small house consumes less energy than a greener large house and uses fewer building materials, which expand the carbon footprint. A typical new single-family home in the U.S. is nearly 2,500 square feet today, up from about 1,000 square feet in 1950, even as the average household has shrunk from 3.4 to 2.6 people.

You could make your own clothes with needle and thread using 100% organic cotton sheared from sheep you raised on a Whole Foods diet, but the environmental quality of your wardrobe is ultimately determined by the way you wash it. A recent study by Cambridge University's Institute of Manufacturing found that 60% of the energy associated with a piece of clothing is spent in washing and drying it. Over its lifetime, a T shirt can send up to 9 lbs. of carbon dioxide into the air.

Where do old fleece jackets go to die? Back to the mountain. Outdoor-gear label Patagonia is collecting used clothing (regardless of brand) made from Polartec and Capilene to melt and make into new fabric and clothes. (Some of that fleece is especially virtuous, starting out as fabric made from recycled plastic.) The company estimates that making polyester fiber out of recycled garments, compared with using new polyester, will result in a 76% energy savings and reduce greenhouse gases 71%.

Almost everything about the Bank of America tower, a soaring skyscraper under construction near Times Square in New York City, has been designed to minimize the use of energy. Take the concrete. Making the stuff from scratch is very energy intensive, so the builders are using a mix of 55% concrete and 45% slag, a waste product from blast furnaces. Mixing slag with concrete saves energy and makes the concrete stronger. The tower will save so-called gray water from washrooms and use it to flush the toilets. The building will also generate much of its own electricity from natural gas, a less potent carbon emitter than coal. These features will account for $3.5 million of a total building cost of $1.2 billion, but the owners expect to recoup that in a few years with all the energy they'll save. When it's finished next year, the tower will be the second highest in the city, but it stands alone as the greenest building in New York.

With clever engineering and an elegantly simple design, Diane von Furstenberg reinvigorated women's fashion in the 1970s with the wrap dress. Can she do the same for a building? Her newest project is a 35,000-sq.-ft. office, showroom and retail store in Manhattan's trendy meatpacking district, all heated and cooled by water pumped from deep underground. This geothermal system taps into water that is a relatively stable 55?F and transfers that heat to warm the building in the winter and cool it in the summer. The building's roof is covered in easy-to-maintain plants and grasses, and has two heliostat mirrors, which track the sun and direct its rays into the building, reducing the use of artificial lights during the day. Who says being environmentally conscious can't be cool—and hot?

High-end hand-me-downs (the smart set calls them vintage) are more ecologically sound than new clothes. Why? Buying a shirt the second time around means you avoid consuming all the energy used in producing and shipping a new one and, therefore, the carbon emissions associated with it. Every item of clothing you own has an impact on the environment. Some synthetic textiles are made with petroleum products. Cotton accounts for less than 3% of farmed land globally but consumes about a quarter of the pesticides. One quick way to change your duds: invite friends over for a closet swap, to which everyone brings a few items they want to trade. It's easy on the environment—and your pocketbook.

Coal is one of the dirtiest fuels around and a major source of the world's carbon dioxide emissions. It's also hard to live without. In the U.S., half the electricity generated comes from coal. What if coal-fired plants stopped spewing their carbon dioxide fumes into the air and instead sequestered them—pumped them deep into the ground for storage?

With transport accounting for more than 30% of U.S. carbon dioxide emissions, one of the best ways to reduce them is by riding something many of us haven't tried since the ninth grade: a bus. Public transit saves an estimated 1.4 billion gal. of gas annually, which translates into about 14 million tons of CO2, according to the American Public Transportation Association.

If you're a true environmentalist, a dyed-in-the-wool greenie, then why not pack up your leafy rural home and move to New York City—preferably to a tall building right in the middle of Manhattan?

The Big Apple is home to the greenest citizens in the U.S. Relatively few New Yorkers own cars—one of the biggest contributors to an individual's carbon emissions. Most walk, bike or ride public transit to work—all more efficient transport than the best hybrids.

Eliminating your paper trail by banking and paying bills online does more than save trees. It also helps reduce fuel consumption by the trucks and planes that transport paper checks. If every U.S. home viewed and paid its bills online, the switch would cut solid waste by 1.6 billion tons a year and curb greenhouse-gas emissions by 2.1 million tons a year, according to Javelin Strategy & Research. Worried about security? Don't be. Just ignore e-mails "phishing" for personal data, and monitor all (electronic) statements for any unauthorized debits. Report problems immediately, and your credit won't take the hit. To avoid unnecessary carbon dioxide-emitting car trips to the bank on payday, ask your employer to directly deposit your paycheck. You'll get your money faster that way too.

Most of the 25 tons of CO2 emissions each American is responsible for each year come from the home. Here are some easy ways to get that number down in a hurry without rebuilding. Open a window instead of running the AC. Adjust the thermostat a couple of degrees higher in the summer and lower in the winter. Caulk and weatherstrip all your doors and windows. Insulate your walls and ceilings. Use the dishwasher only when it's full. Install low-flow showerheads. Wash your clothes in warm or cold water. Turn down the thermostat on the water heater. At the end of the year, don't be surprised if your house feels lighter. It just lost 4,000 lbs. of carbon dioxide.

How green is your abode? A home energy audit, which most utility providers will do free of charge, will tell you the amount of power your household consumes and what you can do to reduce it. The average family can find ways to shave 1,000 lbs. of CO2 emissions each year. Energy auditors use special equipment like blower doors and infrared cameras to help you pinpoint exactly how your house is losing energy. You can also perform a do-it-yourself audit (see time.com/audit), but this is one time you might actually want to be audited by the experts.

More than 600 utilities in 37 states offer green energy, but unless you read the fine print on your bill, you may not know if your power company is one of them. (To find out, visit eere.energy.gov/greenpower.) If you don't live in a green power zone, you can support the industry by buying renewable energy certificates, which allow you to purchase green energy in another part of the country. The extra dollars will dispense green power to the national power grid.

You wouldn't buy a car without knowing its gas mileage. Why not do the same when choosing energy-efficient ovens or even supermarkets and hotels? Energy Star, a rating system by the Environmental Protection Agency, will help you find them. Approved products can be pricier, but they cost less to power. Commercial buildings account for nearly 18% of U.S. greenhouse-gas emissions, but those with the Energy Star label consume 35% less energy than the average. By using Energy Star appliances at home, consumers can reduce their utility bill as much as 30%.

Improving your home's efficiency doesn't have to mean hours in the attic tearing out the insulation. It might be as simple as giving your dear old water heater a warm hug. Wrapping your heater in an insulated blanket—one costs about $10 to $20 at home centers—could save your household about 250 lbs. in CO2 emissions annually. Most water heaters more than five years old are constantly losing heat and wasting energy because they lack internal insulation. If the surface feels warm to the touch, get your heater an extra blankie. You'll both feel better.

Which is responsible for more global warming: your BMW or your Big Mac? Believe it or not, it's the burger. The international meat industry generates roughly 18% of the world's greenhouse-gas emissions—even more than transportation—according to a report last year from the U.N.'s Food and Agriculture Organization.

Arnold Schwarzenegger may have signed the world's toughest anti-global-warming law, but it is Democrat Terry Tamminen, his environmental adviser, who is emerging as the state's real Terminator, winning industry support and the endorsement of a Republican Governor for a mandate to reduce the state's emissions 80% by 2050.

The plastic bags you bring home from the supermarket probably end up in a landfill. Every year, more than 500 billion plastic bags are distributed, and less than 3% of those bags are recycled. They are typically made of polyethylene and can take up to 1,000 years to biodegrade in landfills that emit harmful greenhouse gases. Reducing your contribution to plastic-bag pollution is as simple as using a cloth bag (or one made of biodegradable plant-based materials) instead of wasting plastic ones. For your next trip to the grocery store, BYOB.

Fruit, vegetables, meat and milk produced closer to home rack up fewer "petroleum miles" than products trucked cross-country to your table. How do you find them? Search localharvest.org by ZIP code for farmers' markets, greengrocers and food co-ops in your area. The website, which includes handy contact information in its directory listings, also identifies restaurants that specialize in regional and seasonal ingredients.

Until we can travel by fireplace, Harry Potter-style, the only way to get from Los Angeles to London is by carbon-spewing jet airliner. One simple change can help: adjust the exit and entry points each nation sets for its airspace so that planes can fly in as straight a line as possible. Last year the International Air Transport Association negotiated a more direct route from China to Europe that shaved an average 30 minutes off flight time, eliminating 84,800 metric tons of CO2 annually. Unifying European airspace as a "single sky" could cut fuel use up to 12%.

You won't be able to stop global warming on your wedding day, but your choices can lessen the carbon footprint of your event. For example, if your guests are traveling long distances, offset the carbon emissions from their trips with a donation to renewable—energy projects. The sustainable—wedding website Portovert.com, in partnership with NativeEnergy, a renewable energy company, offers a wedding carbon calculator where couples can enter the number of guests and approximate miles traveled, to calculate the carbon impact of their wedding—related travel.

How can a tie help fight climate change? When you leave it at home. In the "cool biz" summer of 2005, Japanese salarymen swapped their trademark dark blue business suits for open collars and light tropical colors. It was all part of the Japanese government's effort to save energy by keeping its office temperatures at 82.4?F throughout the summer.

A screen saver is not an energy saver. According to the U.S. Department of Energy, 75% of all the electricity consumed in the home is standby power used to keep electronics running when those TVs, DVRs, computers, monitors and stereos are "off." The average desktop computer, not including the monitor, consumes from 60 to 250 watts a day. Compared with a machine left on 24/7, a computer that is in use four hours a day and turned off the rest of the time would save you about $70 a year. The carbon impact would be even greater. Shutting it off would reduce the machine's CO2 emissions 83%, to just 63 kg a year.

Bright green may not be in this season, but eco-friendly makeup has trend written all over it. In February, Cargo Cosmetics launched PlantLove, a botanical lipstick packaged in a 100% biodegradable tube made of polylactic acid—a corn-based renewable resource. When the tube is empty, plant it in the ground, and it sprouts flowers. The product represents only a sliver of the $50 billion industry in the U.S., but it's growing fast. The market for organic personal-care products will increase more than 8% this year.

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Assigning an office switch-off monitor might sound a little like third grade, but it could cut carbon emissions by reducing electricity use, not to mention extending equipment life and lowering maintenance costs. It's not exactly glamorous work: walking the halls to make sure that computers, monitors, desk lights, printers and fax machines are turned off daily. Air conditioners and overhead lights can be timed for turnoff: Aim for off-peak energy use to be about one-fifth of peak use. In the morning, the switch-on monitor takes over.

What if we could build a giant mirror in space to deflect the sun's energy? Or inject sulfur into the stratosphere to cool the earth? Scientists are examining such sci-fi methods as a gigantic Plan B should efforts to end carbon emissions fail. Geoengineering, as the field is called, involves rearranging the environment on a planetary scale. The best-known idea involves the so-called space mirrors. Roger Angel, an astronomer at the University of Arizona, suggests putting trillions of small, ultra-thin lenses into orbit, enough to form a cylindrical cloud with a diameter half the size of the Earth's equator and a length of 60,000 miles. Placed 1.5 million km above the Earth's surface, the massive mirror would reduce the amount of sunlight reaching the planet by about 2%, which Angel believes would be enough to offset a significant amount of warming. Implementing this plan would be no mean feat: the mirrors would collectively weigh 20 million tons and cost trillions of dollars. And to get all those lenses into orbit, we'd have to launch rockets every five minutes for 10 years.

Few things rip through the serenity of a Sunday in suburbia like the 70-db wail of a gas-powered leaf blower. Improvements have been made to make them more efficient, but using that motorized hurricane for just an hour still sucks down 1 pt. of gas and oil. With more than 30 million acres of lawn in the U.S., it's a high price to pay for a job that can be done almost as well, if somewhat more slowly, with a rake. Besides, you can't lean on a leaf blower when you're done.

Americans recycled 42 million tons of paper last year—50% of what they used—but still pulverized the rest. Paper does grow on trees: 900 million of them every year become pulp and paper.

We can reduce that number by buying more recycled paper. It uses 60% less energy than virgin paper. Each ton purchased saves 4,000 kW-h of energy, 7,000 gal. of water and 17 trees, and a tree has the capacity to filter up to 60 lbs. of pollutants from the air.

To cut back on carbon, environmentalists are using the force of the free market. In carbon-emissions trading, the government puts a cap on how much carbon an industry is allowed to emit from power plants, factories and cars. Innovative companies could meet those caps through actual reductions and earn carbon "credits," which they could sell to industry laggards. Connecticut, Delaware, Maine, New Hampshire, New Jersey, New York and Vermont have agreed on a regional cap-and-trade system. Arizona, California, New Mexico, Oregon and Washington have signed a similar pact. New emissions-reduction technology is sexier, but old-fashioned horse trading might just be more effective.

Paper or plastic? How about neither? All those Styrofoam peanuts and impregnable plastic CD cases cost energy to manufacture and deliver, and that means carbon. You can reduce the amount of packaging with a little consumer vigilance. Give back the extra napkins or unwanted sugar packets; carry that gallon of milk by its handle. True eco-nerds will even bring their own cup to a Starbucks.

One of the most ambitious of the Kyoto Protocol's plans to help cut greenhouse gases was the Clean Development Mechanism, through which companies in the rich world could earn credit not for reducing their own emissions but for investing in energy efficient projects in the developing world. The idea, which was included in the Kyoto Protocol at the insistence of the U.S., has helped create a global trade in carbon credits, in addition to the broader emissions-trading market. So far, hundreds of projects have been approved, some two-thirds of them in just three countries: Brazil, China and India. Together, the projects save the equivalent of about 115 million tons of carbon dioxide per year, and range from installing more energy efficient machinery in paper and cardboard factories to building wind turbines to generate renewable power.

The U.S. spends more than $5 billion a year on fossil-fuel-derived fertilizers that leak chemicals into the ground and accelerate the release of nitrous oxide—a greenhouse gas. Try alternatives, from old-fashioned compost to grass clippings, which contain about 4% nitrogen. More adventurous gardeners use a homemade fertilizer mix that includes seaweed extracts for potassium and fish proteins and oils for nitrogen. Or go native and embrace wildflowers and indigenous grasses. Weeds are a matter of taste.

The essential injustice of global warming is that the poor will suffer the worst effects while contributing far less to carbon emissions than the rich. So here's a radical solution: divide greenhouse-gas emissions by population, and give everyone in the world the right to emit the same amount of carbon—a personal carbon allowance.

Essentially, allowances are a cap-and-trade scheme for individuals. They set a clear target and let the market work out the details. Bike to work and live beneath your allowance, and you can sell your carbon credits to energy spendthrifts who refuse to give up their SUVs. The balance of your allowance might be recorded on a sort of carbon-debit card, so if you buy that SUV, you'll be spending carbon too. If you want to keep living as if it's 1989, all you have to do is pay for it.

The next time you get behind the wheel of your car, turn to the passenger seat. Chances are, it's empty. In most of the U.S., the single-occupant driver still reigns supreme. Nearly 80% of people drive to work alone; about 38% drive alone in general. In some places, that's starting to change. As part of its Clean Air Act, Washington State appealed to business with incentives to encourage employees to drive less or at least stop driving alone. A state tax credit benefits companies that encourage their employees to carpool, ride the bus, walk or bike to work, or work a compressed workweek. The result: about 20,000 fewer vehicle trips each morning since the program started in 1991, saving commuters $13.7 million and 5.8 million gallons of gas, and reducing 78,000 tons of air pollutants and CO2-equivalent gases.

Feeling full of climate-change guilt, Americans are snapping up carbon offsets from Web-based retailers and nonprofits. Unlike mandatory allowances, offsets allow consumers to pay voluntarily to reduce carbon emissions by a quantity equal to their estimated contribution. The money typically funds clean-energy projects, pollution control, tree planting and forest conservation. But offsets are picking up skeptics along with customers. Critics say consumers have little assurance that the projects they underwrite really reduce emissions and warn that those buying offsets may sometimes pay for improvements that would have happened anyway. They also argue that carbon-offset trading distracts from the urgent need to change U.S. policies to address global warming.

Homes in London account for 44% of the city's CO2 emissions, more than twice the amount spewed out through transport. Worse still, the city needs to add 35,000 more every year to keep up with London's ballooning population.

So you own a plain-vanilla, nonhybrid, American-made gas guzzler and can't afford (or can't wait for) a hybrid. Now what? Just giving your engine a tune-up can improve gas mileage 4% and often much more. Replacing a clogged air filter can boost efficiency 10%. And keeping tires properly inflated can improve gas mileage more than 3%. The bottom line? If you can boost your gas mileage from 20 to 24 m.p.g., your old heap will put 200 fewer pounds of CO2 into the atmosphere each year.

United Parcel Service took a detour to the right on its way to curb CO2 emissions. In 2004, UPS announced that its drivers would avoid making left turns. The time spent idling while waiting to turn against oncoming traffic burns fuel and costs millions each year. A software program maps a customized route for every driver to minimize lefts.

In metro New York, UPS has reduced CO2 emissions by 1,000 metric tons since January. Today 83% of UPS facilities are heading in the right direction; within two years, the policy will be adopted nationwide.

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It seems like simple arithmetic: a tree can absorb up to a ton of carbon dioxide over its lifetime, so planting one should be an easy way to mitigate climate change. Turns out it's not so simple. Recent studies have shown that trees in temperate latitudes—including most of the U.S.—actually have a net warming effect on the climate. The heat that dark leaves absorb outweighs the carbon they soak up.

The poor coal plant: not only does it emit environment-damaging compounds, but even the newest (which can cost as much as $3 billion to build) lose more than half the heat generated when the coal is burned. But in co-generation power plants, that excess heat is captured and reused for domestic and industrial heating, nearly doubling a plant?s efficiency. The process is similar to what goes on in your car—think of the engine as a mini cogeneration plant. When the engine runs, it create excess heat while driving the car, and in cold weather, that waste product is used to warm the car.

Going on vacation doesn't have to mean leaving your green conscience at home. The car-sharing service Zipcar rents hybrids cars in five U.S. cities, Toronto and London. A few specialty companies offer rental cars that run on biodiesel fuel, a clean-burning substance derived from renewable sources like vegetable oil. Bio-Beetle rents eco-friendly cars, ranging from Passats to Jeeps, in Hawaii and Los Angeles. A week's rental in L.A. runs from $200 to $300. And competitor EV Rental Cars has started to expand beyond the West Coast.

If cars have to meet energy standards, why don't power plants? Carbon-emission standards limiting the amount of CO2 that a new power plant can spew are in place in a handful of states. California's tough new rules virtually exclude new coal plants until clean-coal technology comes on line, and could establish a national standard—just as they might for auto emissions. A federal carbon standard would be aggressively opposed by power companies that depend on coal. But it could also spur investment in renewables, clean coal and even nuclear (that's another fight) more rapidly than carbon taxes or cap-and-trade systems. With 159 new coal-powered plants slated for the next decade, a critical choice is looming.

Georg Zielke, his wife and kids share a five-bedroom "passive house" in Darmstadt, Germany, with heating costs 90% lower than their neighbors'. Extra insulation and state-of-the-art ventilation recycle the energy from passive sources such as body heat, the sun and household appliances to warm the air. When it gets really cold, the Zielkes just turn on the TV.

The chance to buy a carbon offset—in essence, an emissions indulgence—appeals to the environmental sinner in all of us. But there is an older path to reducing our impact on the planet that will feel familar to Evangelical Christians and Buddhists alike. Live simply. Meditate. Consume less. Think more. Get to know your neighbors. Borrow when you need to and lend when asked. E.F. Schumacher praised that philosophy this way in Small Is Beautiful: "Amazingly small means leading to extraordinarily satisfying results."

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