Anthropogenic climate change is worsening North American pollen seasons

William R L Anderegg, School of Biological Sciences, University of Utah, Salt Lake City, UT 84112;, John T Abatzoglou, Management of Complex Systems Department, University of California, Merced, CA 95343;, Leander D L Anderegg, Department of Integrative Biology, University of California, Berkeley, CA 94720;, Department of Evology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106;, Leonard Bielory, Center for Environmental Prediction, Rutgers University, New Brunswick, NJ 08854;, Department of Medicine, Allergy and Immunology and Ophthalmology, Hackensack Meridian School of Medicine, Nutley, NJ 07110;, New Jersey Center for Science, Technology and Mathematics, Kean University, Union, NJ 07083;, Patrick L Kinney, School of Public Health, Boston University, Boston, MA 02118;, Lewis Ziska, Mailman School of Public Health, Columbia University, New York, NY 10032