Climate change could bring with it a wide variety of health problems, according to a study of possible effects in Washington state, released today by Physicians for Social Responsibility. For example, higher temperatures could increase concentrations of ground-level ozone and other air pollutants, aggravating asthma cases, and expand the habitat of ticks that carry Lyme disease. Meanwhile, separate research has found that while some plants may grow faster in a world with greater concentrations of carbon dioxide, the nutritional value of the plants’ leaves might drop significantly.