The answer to global warming may be blowing in the wind. It's probably also driving on four wheels and could be in your next tank of gas.
Scientists are cooking up solutions based on current technology that they say could dramatically turn down the heat of global warming over the next 50 years.
Innovations such as cheaper wind power, gas-electric hybrid cars and gas cards that generate funds for climate change projects already are available. Introducing them across the nation could put a dent in the growth of greenhouse gases that are warming the planet, scientists say.
The concentration of carbon dioxide -- a potent greenhouse gas -- is likely to double before the end of the century, the United Nations says. Scientists say further warming is inevitable as greenhouse gas emissions climb but that the worse effects can still be avoided.
"The question now is not 'whether to adapt?' but 'how to adapt?' " says a 2004 U.N. report on climate change.
The solutions, say experts, must come from action by politicians, business people, scientists and individuals. Over the next century, power could be derived from sources that release less carbon dioxide into the atmosphere such as nuclear fusion, hydrogen fuel cells and more efficient combustion engines.
Scientists: Technology already exists
Technology is a crucial component to meeting the challenge of global warming, say climate researchers and policy experts.
"You need technology," says Elliot Diringer, international strategies director with the Pew Center on Global Climate Change. "There's no question about that. The question is, 'What is the most efficient way to not only generate the technology but get it deployed.' "
The Intergovernmental Panel on Climate Change, a U.N. body issuing regular assessments on the climate, says innovation has advanced faster than expected. It estimates technological improvements could reduce greenhouse gas emissions below 2000 levels within 20 years and avert even more risky levels of such concentrations.
The IPCC has estimated that technological improvements could some time between 2010 and 2020 reduce greenhouse gas emissions to levels below those in the year 2000.
"We need to move as fast as we can," Diringer says. "The longer we wait to take concerted action, the greater the impacts will be ... the more it will cost to achieve the reduction."
Technology with the greatest potential to reduce greenhouse gas emissions already exists, say Princeton University scientists Stephen Pacala and Robert Socolow in a 2004 study published in the journal Science.
Improving efficiency and conservation could slash billions of tons in atmospheric emissions of greenhouse gases each year. Improvements such as efficient engineering, better gas mileage and new fuel sources for vehicles and power plants have the potential to halt growth of emissions by around 2050, according to the study.
"It is important not to become beguiled by the possibility of revolutionary technology," the Princeton authors write in Science. "Humanity can solve the carbon and climate problem in the first half of this century simply by scaling up what we already know how to do."
The scientists picked seven actions that they say could stabilize the climate by 2054. They focused on technology already in place that simply needs to be expanded -- a lot.
Cars are an easy target. Each gallon of gas burned releases about 20 pounds of heat-trapping carbon dioxide into the atmosphere, according to the Environmental Protection Agency. That's a lot of carbon for the 2 billion cars that may be on the road by 2054, nearly four times the number today, the authors report.
The Science article suggests that doubling the average fuel efficiency of cars from 30 miles per gallon today to 60, switching to wind-generated hydrogen fuels or halving the annual number of miles traveled per car to 5,000 could slash carbon dioxide emissions. The savings would provide one-seventh of the total cuts needed to stabilize U.S. emissions, the article states.
Other such actions include replacing coal power plant capacity with natural gas, doubling nuclear power capacity to 700 gigawatts or adding 2 million wind turbines, about 50 times the current number.
Low-tech methods exist, too. Halting tropical deforestation by 2054, instead of halving it, as well as reforesting about 965,255 square miles in the tropics would slash emissions by one-seventh, the Science article says. Better agriculture practices that slow erosion and reduce plowing would have the same effect, the article says.
In addition, scientists are eyeing plenty of other technologies being developed to stabilize emissions.
Burying carbon dioxide allows fossil fuel companies to continue pumping oil while mitigating greenhouse emissions. The United Nations estimates by 2050 it should be possible to store half of cumulative global emissions in underground reservoirs at reasonable prices.
The U.S. government already has launched a test project at a West Virginia coal power plant. The energy company BP sends 1 million tons of carbon dioxide each year beneath the sands of the Sahara desert at one of its facilities in Algeria.
These carbon sequestration projects send millions of tons of carbon dioxide gas into underground geologic formations such as aquifers or gas beds now filled with water, natural gas or oil.
The risks of such techniques include leakage of carbon dioxide from underground reservoirs that may endanger human life and the environment. Scientists are studying techniques to find which rock formations permanently store gases such as carbon dioxide.
Renewable power is a major facet of reducing global warming emissions, according to the United Nations.
Because most renewable energy sources -- wind, ocean tides, solar, biomass fuel -- emit less carbon dioxide into the atmosphere than they absorb, they do not add to climate change. The share of renewables in the world energy supply accounts for at least 14 percent of the total, the United Nations estimates.
The price of these renewable fuels and technology is plummeting as demand grows and hardware improves. "Green" tariffs, already introduced in some European countries, guarantee premium prices for energy derived from renewable sources.
States such as New York and California also require utilities to generate a fraction of their energy supply from renewables.
Carbon emissions trading is designed to make global warming prevention affordable, according to the U.N. Convention on Climate Change
Under the Kyoto Protocol, participating countries agree to emit a certain amount of carbon. If a country cannot afford to meet its carbon emissions limit, it can buy "credits" from a country that has produced less than its allotted amount.
Although critics say there are significant problems under the Kyoto system, the United Nations says emissions trading allows countries gradually to eliminate carbon dioxide while preventing some economic hardships of reducing emissions growth.
Companies also are devising ways for businesses and individuals to offset greenhouse emissions. Oregon-based Climate Neutral Network says it soon will offer air travelers access to "Cool Class" air travel in which a portion of airline fares, negotiated through contracts with different companies, are invested in ways to reduce greenhouse emissions.
BP Amoco also recently created a "Climate Cool Fuel" gas card. As a preferred supplier, Climate Neutral says BP Amoco can increase sales in return for investing in mitigating emissions. It estimates "Cool Fuel" could offset U.S. emissions by almost 1 percent if a significant number of oil customers participate.