On Earth Day, Harvard Chan experts talk climate and health The impact of climate change on health is far-reaching, according to experts from Harvard T.H. Chan School of Public Health. It can lead to higher levels of air pollution, more extreme weather events, the spread of infectious diseases, and greater risk of pandemics, they said in various media appearances on Earth Day, April 22, 2021. A NowThis Earth documentary featured Aaron Bernstein, interim director of Harvard Chan School’s Center for Climate, Health, and the Global Environment (Harvard Chan C-CHANGE) and a pediatrician, and Gina McCarthy, former C-CHANGE director, chair of its board of advisers, and currently White House National Climate Adviser in the Biden administration.