* HOW ENERGY AFFECTS THE GREENHOUSE-
A typical household uses about 7,000-10,000 kilowatt-hours (kwh) of electricity every year. Each kwh we save keeps about 1.5 pounds of CO2 out of the atmosphere.
* Households use about 750 therms of natural gas a year, on the average. Some of it leaks out of pipes and contributes directly to the greenhouse effect. The rest produces CO2 when it burns -- about 12 pounds for every therm.
* The average car uses 500 gallons of gasoline in a year. Every gallon burned adds 20 pounds of carbon dioxide to the air.
* Even wasting water contributes to the greenhouse effect because of the energy it took to pump, purify and treat that water. According to the Natural Resources Defense Council, about 6 pounds of CO2 are emitted for every 1,000 gallons of water we use.
Said another way, electricity creates about 10,000 pounds per household per year,
gas produces another 10,000, and each car about 10,000. This would mean if the average household has two cars, the amount of CO2 contribution would be about the same for cars as for lighting, heating, etc.
If this can be confirmed elsewhere, it would suggest that, at least with regard to the CO2 effect on global warming, we can make as many gains from reducing use of energy in homes as with our personal cars.