Global warming occurs because carbon dioxide (CO₂) and other gasses released by the combustion of fossil fuels are building up in the atmosphere and preventing the sun's heat from escaping back into space. Many scientists, as well as the U.S. Environmental Protection Agency, are concerned that global warming could lead to serious changes in our climate, causing more dangerous storms and hurricanes, rising sea levels, and the spread of tropical diseases. In December, delegates from around the world will meet in Japan to determine ways their countries can reduce fossil fuel emissions. You can do your part at home:

Drive a fuel-efficient car. If your new car gets 10 mpg more than your old one, you can reduce CO2 emissions by 2,500 pounds a year.

Walk, bike, carpool or use mass transit. If you leave your car at home two days a week, you'll reduce CO2 emissions by 1,590 pounds a year.

Weatherize your home. Insulate walls and ceilings, caulk and weatherstrip around doors and windows, and wrap your water heater in an insulating jacket to reduce CO2 emissions by up to 4,000 pounds a year.

Use energy-efficient appliances. If you replaced your existing refrigerator with a high-efficiency model, you'd reduce your CO2 emissions by 220 pounds a year. Energy-efficient appliances are now available for microwave ovens, stoves, dishwashers and computers, as well.

Reduce, reuse and... Recycle? You guessed it. Buying food and other products in reusable or recyclable packaging can reduce CO2 emissions by 230 pounds a year, while recycling all of your home's waste newsprint, cardboard, glass and metal can reduce emissions an additional 850 pounds a year.

At the office, consider these additional ideas:

Turn off the power. Flick off lights and turn off computers and other equipment when you leave your office for long periods of time.

Use e-mail. Use electronic mail and electronic faxes rather than paper and the postal system whenever possible.

Use a reusable mug. Choose reusable over throwaways as much as possible.

Support company programs to save energy. Participate in company carpools, waste paper recycling programs and environmentally friendly landscape strategies. Tele-commute if possible.