Scientific evidence supports the view that the earth’s climate is changing. A broad array of organizations (federal, state, local, multilateral, faith-based, private and nongovernmental) is working to address climate change. Despite this extensive activity, the public health effects of climate change remain largely unaddressed. CDC considers climate change a serious public health concern.Some of the impacts on health that we will see might include: direct effects of heat, air-polution related effects, increased allergies, water and food-born diseases, vector and zoonotic diseases, food and water scarcity, mental health problems and impacts on chronic diseases. Dr. Gerberding was ready to provide Congress with specifics on each of those problems but Pres. Bush said no.
Bush also didn't want you to know that "sophisticated models to predict climate and heat exist". You can read the entire testimony, complete with redacted portions, here.