Nurses Warn of Escalating Effects of Climate Change on Public Health. The nation’s largest U.S. organization of nurses today criticized the new State Department report on the Keystone XL Pipeline, presumably intended to encourage a green light on construction of the controversial project, for paying inadequate attention to the serious consequences on public health. “There is broad concern about the harmful health effects linked to both the extraction and transport of tar sands, as well as how the Pipeline will accelerate the steadily worsening erosion of health we see every day as a result of climate change,†said Jean Ross, RN, co-president of National Nurses United.