Cool your home, warm the planet.

When more than two dozen countries undertook in 1989 to fix the ozone hole over Antarctica, they began replacing chloroflourocarbons in refrigerators, air conditioners and hair spray.

But they had little idea that using other gases that contain chlorine or fluorine instead also would contribute greatly to global warming.

CFCs destroy ozone, the atmospheric layer that helps protect against the sun’s most harmful rays, and trap the earth’s heat, contributing to a rise in average surface temperatures.

In theory, the ban should have helped both problems. But the countries that first signed the Montreal Protocol 17 years ago failed to recognize that CFC users would seek out the cheapest available alternative.

The chemicals that replaced CFCs are better for the ozone layer, but do little to help global warming. These chemicals, too, act as a reflective layer in the atmosphere that traps heat like a greenhouse.

That effect is at odds with the intent of a second treaty, drawn up in Kyoto, Japan, in 1997 by the same countries behind the Montreal pact. In fact, the volume of greenhouse gases created as a result of the Montreal agreement’s phaseout of CFCs is two times to three times the amount of global-warming carbon dioxide the Kyoto agreement is supposed to eliminate.

This unintended consequence now haunts the nations that signed both U.N. treaties.

Switzerland first tried in 1990 to sound an alarm that the solution for plugging the ozone hole might contribute to another environmental problem. The reaction?

“Nothing, or almost,” said Blaise Horisberger, the Swiss representative to U.N.-backed Montreal treaty. “We have been permanently raising this issue. It has been really difficult.”

Horisberger, a biologist with the Swiss Agency for the Environment, Forests and Landscape, kept trying. Finally, the first formal, secret talks on the subject were held in Montreal last month.

“Saving the ozone layer by reducing CFCs and at the same time promoting alternatives was an urgent crisis in the early years of the Montreal Protocol,” said Marco Gonzalez, the treaty’s executive secretary, in Nairobi, Kenya. “Now there is always a need to find new substances which are safe, energy-efficient and also have minimal impact across a range of environmental issues.”

$2 billion investment

The Montreal Protocol, which now has 189 member nations, is considered one of the most effective environmental treaties. Almost $2.1 billion has been spent through an affiliated fund to prod countries to stop making and using CFCs and other ozone-damaging chemicals in refrigerators, air conditioners, foams and other products.

Scientists blame CFCs for poking a huge, seasonal hole in the stratospheric ozone layer about 7 miles to 14 miles over Antarctica. Last year, the ozone hole peaked at about 10 million square miles, or the size of North America. That was below the 2003 record size of about 11 million square miles. Scientists expect the hole will not heal until 2065.

CFCs also are thinning the ozone layer over the Arctic and, to a lesser extent, globally. As the protective layer thins, more ultraviolet radiation gets through, increasing people’s risk of skin cancer and cataracts and threatening more plants and animals with extinction.

Some of the replacement chemicals whose use has grown because of the Montreal treaty — hydrochloroflourocarbons, or HCFCs, and their byproducts, hydrofluorocarbons, or HFCs — decompose faster than CFCs because they contain hydrogen.

But, like CFCs, they are considered potent greenhouse gases that harm the climate — up to 10,000 times worse than carbon dioxide emissions.

The Kyoto treaty’s goal is to reduce carbon dioxide emissions from power plants, motor vehicles and other sources that burn fossil fuels by about 1 billion tons by 2012.

Use of HCFCs and HFCs is projected to add the equivalent of 2 billion to 3 billion tons of carbon dioxide emissions to the atmosphere by 2015, U.N. climate experts said in a recent report. The CFCs they replace also would have added that much.

“But now the question is, who’s going to ensure that the replacements are not going to cause global warming?” said Alexander von Bismarck, campaigns director for the Environmental Investigation Agency, a nonprofit watchdog group in London and Washington. “It’s shocking that so far nobody’s taking responsibility.”

“A massive opportunity to help stave off climate change is currently being cast aside,” he said.

These cylinders at a Chinese facility contain HCFC-22 refrigerant chemicals.

The U.N. report says the atmosphere could be spared the equivalent of 1 billion tons of carbon dioxide emissions if countries used ammonia, hydrocarbons, carbon dioxide or other ozone-friendly chemicals, rather than HCFCs and HFCs, in foams and refrigerants. Such alternatives are more common in Europe.

“This potential of not using greenhouse gases is not fully used,” said Horisberger, the Swiss official. “It’s because of many reasons — technical, big commercial interests.”

Industry is split over how to replace CFCs and HCFCs.

One of the biggest producers of fluorine-based refrigerants, Honeywell International Inc., says it is discontinuing its use of “the older technology, environmentally unfriendly CFC and HCFC refrigerants,” and replacing those chlorine-containing chemicals with HFCs in retrofits and in new equipment.