WASHINGTON - Have you heard the news? Scientists have found a planet that can support life. Parts of its atmosphere are too hot for year-round habitation, its gases impede breathing and surface conditions are sometimes fatal. But by constructing a network of sealed facilities, tunnels and vehicles, humans could survive on this planet for decades, and perhaps even centuries.

The planet is called Earth.

If you've seen this planet lately, you know what's going on: record-shattering temperatures, scores of Americans dead. By summer's end, the toll will be in the hundreds. It's not as bad as 2003, when a heat wave killed more than 35,000 people in Europe. But according to global-warming forecasts, within 40 years, every other summer will be like that one.

Thank goodness for air conditioning. To keep old folks alive, cities from Washington to Los Angeles are opening artificially cooled buildings to the public.

Meanwhile, people are lining up to buy window units. According to the Air-Conditioning and Refrigeration Institute, shipments of air conditioners and heat pumps have tripled over the past three decades.

The percentage of single-family homes built with central air has gone from 36 to 87. The percentage of cars built with air conditioning has risen from 61 to 98. In 1970, 42 percent of occupied mobile homes had it. By 2003, that percentage had more than doubled.

It's a heartwarming -- or, more precisely, a heart-cooling -- story. Unfortunately, the story doesn't end there. Air conditioning takes indoor heat and pushes it outdoors. To do this, it uses energy, which increases production of greenhouse gases, which warm the atmosphere. From a cooling standpoint, the first transaction is a wash, and the second is a loss. We're cooking our planet to refrigerate the diminishing part that's still habitable.

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All over the country, power consumption is breaking records, and air conditioning is a huge reason why. We use about one-sixth of our electricity to cool ourselves. That's more than the total electricity consumption of India, a country whose population exceeds 1 billion. To get the electricity, we burn oil and coal. We also run air conditioners in our cars, which reduces urban fuel efficiency by up to four miles per gallon, at an annual cost of 7 billion gallons of gasoline.

More burning of oil and coal means more greenhouse gases. Stan Cox, a scientist at the Land Institute, calculates that air-conditioning the average U.S. home requires 3,400 pounds of carbon dioxide production per year. The effects of this are particularly bad at night.

Over the past five summers, very high minimum daily temperatures -- those that score in the top 10 percent historically -- have been far more widespread in this country than during any other five-year period. This is what's killing people. Outdoor air used to cool at night, allowing us to recover from the day's heat. Now it doesn't. To fuel our air conditioning, we're destroying nature's.

The hotter it gets, the more energy we burn. In 1981, one in three American households with central air used it all summer long. By 1997, more than half did. Countries once cooled by outdoor air now cool themselves. In Britain, 75 percent of new cars have air conditioning. In Canada, energy consumption for residential cooling has doubled in 10 years, and half the homes now have central air or window units. Kuujjuaq, an Eskimo village 1,000 miles north of Montreal, just bought 10 air conditioners. According to the mayor, it has been getting hot lately.

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