 Climate change should be treated as a public health issue, especially by the United States, the world's biggest long-term emitter of greenhouse gases, health and ecology experts said on Tuesday. An Earth transformed by climate change could lead to more climate-related diseases, especially those transmitted by insects and those borne by water supplies, the experts said at a meeting of the American Public Health Association. The United States and other rich countries bear special responsibility because their climate-warming emissions will have a disproportionate impact on poor countries that emit the least and have the fewest resources to deal with public health problems, said Jonathan Patz of the University of Wisconsin. "There is ... an issue of disproportional vulnerability," Patz said at a news conference. "But ... in the industrialized world, because we live in a globalized economy, an increase in disease anywhere in the world really puts everyone at risk." Health hazards related to climate change include severe heat waves and droughts, which can affect the food and water supply; more severe storms; and more ground-level ozone, also known as smog, which is sensitive to temperature and can affect people with breathing problems such as asthma. "Climate change is one of the most serious public health threats facing our nation," said Dr. Georges Benjamin, the association's executive director. "Yet few Americans are aware of the very real consequences of climate change on the health of our communities, our families and our children." The United States has long been the top emitter of climate-warming greenhouse gases, notably the carbon dioxide from coal-fired power plants and petroleum-powered vehicles. At least one study this year found China was overtaking the United States on this score, but over time, the United States has still emitted more. "In the aggregate, we are still the number one country responsible for climate change," he said, noting that carbon dioxide stays in the environment for about 70 years. Patz and Benjamin stressed that rising awareness of climate change can be seen as an opportunity to improve public health. To that end, Benjamin announced a six-month plan to develop recommendations to help public health professionals deal with the situation. Public health professionals include doctors, nurses, lawyers and health educators. The recommendations are expected to be released in April, Benjamin said.