October 19, 2015
By the end of the century, spring could arrive almost three weeks earlier in parts of the United States. This is according to a report published recently in Environmental Research Letters by UW-Madison scientists and collaborators at the U.S. Fish and Wildlife Service and U.S. Geological Survey.
The onset of spring plant growth has shifted earlier over the past several decades due to rising global temperatures. Using extended spring indices and downscaled climate data, the researchers (from UW-Madison: postdoctoral fellow Andrew Allstadt; Nelson Institute Center for Climatic Research senior scientist Steve Vavrus; and Forest and Wildlife Ecology Professors Anna Pidgeon and Volker Radeloff) projected changes in spring onset through 2100 in the contiguous United States. Averaged across the study region, the team found a median shift of 23 days earlier.
Accelerated spring onset carries implications for agriculture and for wildlife; for instance, earlier warm weather can cause mismatches between the availability of plant resources and dependent animals, and potentially lead to more "false springs," when subsequent freezing temperatures damage new plant growth.
"Our projections show that winter will be shorter – which sounds great for those of us in Wisconsin," Allstadt said in a statement. "But long-distance migratory birds, for example, time their migration based on day length in their winter range. They may arrive in their breeding range to find that the plant resources that they require are already gone."
While the findings showed an increased false spring risk in the Great Plains and portions of the Midwest, risk remained constant or decreased elsewhere. And due to the complex effects of global climate change on seasonal shifts, the authors note, local predictions of change are difficult. View the full report.