Bioclimatic changes in false springs across the United States
Climate warming yields potentially longer growing seasons in energy-limited portions of the Earth, offering potential benefits to ecological and agricultural systems. Species receptive to thermal accumulation during the spring may break dormancy and begin development earlier in the year; however, advances in phenological timing may leave early-stage vegetation growth vulnerable to cold damage when hard freezes follow green-up resulting in a false spring. With continued widespread warming of the global land surface in the coming decades, it is relevant to examine how false springs may change under various representative concentration pathways. Spatiotemporal patterns of green-up dates, last spring freezes, and false springs are modeled across the contiguous United States from 1950 to 2099 using downscaled climate projections. Results indicate widespread advancement in the timing of green-up and last spring freeze dates over the period, with last spring freezes trending earlier in the year relative to green-up. Although regionally variable, these changes result in an overall reduction of false springs across the US.
Alexander Peterson is a first-year Master's student in the Geography Department at the UI. Studying under Dr. John Abatzoglou, his research explores applied aspects of climate and climate change. Prior to starting his Master's this fall, Alexander worked as a Natural Resources and Environmental Technician for Naval Facilities Engineering Command in the Puget Sound region of Washington, where he surveyed and mapped various natural resources and wildlife species. He graduated summa cum laude from the UI in the spring of 2013, majoring in Geography with a minor in Climate Science. His current area of study focuses on microclimates and their application to agricultural systems and ecology, in addition to modeling future changes in freeze events and spring vegetation growth across the United States.