Cutting global warming pollution would not only make the planet healthier, it would make people healthier too, new research suggests.

Slashing carbon dioxide emissions could save millions of lives, mostly by reducing preventable deaths from heart and lung diseases, according to studies released Nov. 25 and published in a special issue of The Lancet British medical journal.

"Relying on fossil fuels leads to unhealthy lifestyles, increasing our chances for getting sick and in some cases takes years from our lives," U.S. Health and Human Services Secretary Kathleen Sebelius said in a telecast briefing from her home state of Kansas. "As greenhouse gas emissions go down, so do deaths from cardiovascular and respiratory diseases. This is not a small effect."

Instead of looking at the health ills caused by future global warming, as past studies have done, this research looks at the immediate benefits of doing something about the problem, said Linda Birnbaum, director of the U.S. National Institute of Environmental Health Sciences. That agency helped fund the studies along with the Wellcome Trust and several other international public health groups.

The calculations of lives saved were based on computer models that looked at pollution-caused illnesses in certain cities. The figures are also based on the world making dramatic changes in daily life that may at first seem too hard and costly to do, researchers conceded.

Some possible benefits seemed highly speculative, the researchers conceded, based on people driving less and walking and cycling more. Other proposals studied were more concrete and achievable, such as eliminating cook stoves that burn dung, charcoal and other polluting fuels in the developing world.

And cutting carbon dioxide emissions also makes the air cleaner, reducing lung damage for millions of people, doctors said.

For example, switching to low-polluting cars in London and Delhi, India, would save 160 lost years of life in London and nearly 1,700 in Delhi for every million residents, one study found. But if people also drove less and walked or biked more, those extra saved years would soar to more than 7,300 years in London and 12,500 years in Delhi because of less heart disease.

"The science is really excellent; the modeling is quite good," said Dr. Paul Epstein of the Harvard School of Medicine's Center for Health and the Global Environment. "It really takes the whole field a step farther."