Ice phenology and effects of climate change on lakes
Long term records of ice phenology, the timing of freeze and breakup, and ice cover duration have proven to be useful indicators of climate change. Ice phenology is sensitive to both water body-specific characteristics (e.g., depth, surface area, and elevation) and broader scale meteorological variables (e.g., temperature and snow depth). The interplay among these factors complicates the response of individual lakes to climate change. In collaboration with John Magnuson and Barbara Benson at the University of Wisconsin Center for Limnology, we have been studying temporal and spatial patterns in ice phenology change at scales from the Great Lakes region to the entire Northern Hemisphere.
Much of the data that we use comes from citizen scientists who have kept records of freeze and breakup dates. We’re always interested in including new records of freeze and thaw dates in the database. If you know of any such records, please don’t hesitate to get in touch.
Ice phenology records from lakes throughout the Northern Hemisphere show dramatic evidence of climate warming. In the Laurentian Great Lakes region, between 1975 and 2004, the average freeze date increased by 10 days and the average thaw date decreased by 6 days. The period of ice cover is shrinking from both ends. Rates of ice cover loss, however, are not the same in all places. Ice cover is shrinking most rapidly along the southern boundary of the region in which lakes routinely freeze. Lakes farther north are losing ice at a relatively slower rate. Gesa Weyhenmeyer and colleagues have an elegant explanation for this phenomenon that relates to nonlinear changes in the period of time that temperatures are below freezing.
Benson, B., Magnuson, J.J., Jensen, O.P., Card, V.M., Hodgkins, G., Korhonen, J., Livingstone, D.M., Stewart, K.M., Weyhenmeyer, G.A., Granin, N.G. 2012. Extreme events, trends, and variability in Northern Hemisphere lake-ice phenology (1855 - 2005). Climatic Change. 112:299-323. PDF
Weyhenmeyer, G. A., D. M. Livingstone, M. Meili, O. P. Jensen, B. Benson, J. J. Magnuson. 2010. Large geographical differences in the sensitivity of ice-covered lakes and rivers in the Northern Hemisphere to temperature changes. Global Change Biology. doi: 10.1111/j.1365-2486.2010.02249.x PDF
White, M.A., K.M. de Beurs, K. Didan, D.W. Inouye, A.D. Richardson, O.P. Jensen, J. O’Keefe, G. Zhang, R.R. Nemani, W.J.D. van Leeuwen, J.F. Brown, A. de Wit, M. Schaepman, X. Lin, M. Dettinger, A.S. Bailey, J. Kimbal, M.D. Schwartz, D.D. Baldocchi, J.T. Lee, and W.K. Lauenroth. 2009. Intercomparison, interpretation, and assessment of spring phenology in North America estimated from remote sensing for 1982-2006. Global Change Biology. doi: 10.1111/j.1365-2486.2009.01910.x PDF
Jensen, O.P., B.J. Benson, J.J. Magnuson, V.M. Card, M.N. Futter, P.A. Soranno, K.M. Stewart. 2007. Spatial analysis of ice phenology trends across the Laurentian Great Lakes region during a recent warming period. Limnology & Oceanography 52:2013-2026. PDF
Magnuson, J. J., B. J. Benson, O. P. Jensen, T. B. Clark, V. Card, M. N. Futter, P. A. Soranno, K. M. Stewart. 2005. Persistence of coherence of ice-off dates for inland lakes across the Laurentian Great Lakes region. Verh. Internat. Verein. Limnol. 29:521-527. PDF
Photo credits Olaf Jensen, John Magnuson, Brant Allen, Jeremy Monroe | Site design Freshwaters Illustrated