Is Western North America's Water Supply Imperiled by the Mere Maintenance of Earth's Current Climate?
Wolfe, B.B., Edwards, T.W.D., Hall, R.I. and Johnston, J.W. 2011. A 5200-year record of freshwater availability for regions in western North America fed by high-elevation runoff. Geophysical Research Letters 38: 10.1029/2011GL047599.
In their newest study of the subject, the four Canadian researchers expanded the time span of the lake-level history to the past 5200 years, based on new analyses of sediment cores they collected in July of 2004 from North Pond (a lagoon on Bustard Island located at the western end of Lake Athabasca); and in doing so they discovered -- see the figure below -- that "modern society in western Canada developed during a rare interval of relatively abundant freshwater supply -- now a rapidly diminishing by-product of the LIA glacier expansion, which is in agreement with late 20th century decline in Athabasca River discharge identified in hydrometric records (Burn et al., 2004; Schindler and Donahue, 2006)." And, frightenly, their data suggest, as they describe it, that "the transition from water abundance to scarcity can occur within a human lifespan," which, as they caution, "is a very short amount of time for societies to adapt."
The Reconstructed water level history of Lake Athabasca. Adapted from Wolfe et al. (2011).
The data in the figure above also suggest that the peak warmth of the Medieval Warm Period -- which was unrelated to any change in the atmosphere's CO2 content -- was likely significantly greater than the peak warmth that has been experienced to date during the Current Warm Period. And the rapidly declining water level over the last couple of decades -- when earth's temperature was near its modern peak, but exhibited very little trend -- suggests that lake level could continue its rapid downward course if planetary temperatures merely maintain their current values. And, therefore, Wolfe et al. conclude, in the final sentence of their report, that "as consumption of water from rivers draining the central Rocky Mountain region is on an increasing trend, we must now prepare to deal with continental-scale water-supply reductions well beyond the magnitude and duration of societal memory."
Burn, D.H., Abdul Aziz, O.I. and Pictroniro, A. 2004. A comparison of trends in hydrological variables for two watersheds in the Mackenzie River Basin. Canadian Water Resources Journal 29: 283-298.
Johnston, J.W., Koster, D., Wolfe, B.B., Hall, R.I., Edwards, T.W.D., Endres, A.L., Martin, M.E., Wiklund, J.A. and Light, C. 2010. Quantifying Lake Athabasca (Canada) water level during the Little Ice Age highstand from paleolimnological and geophysical analyses of a transgressive barrier-beach complex. The Holocene 20: 801-811.
Schindler, D.W. and Donahue, W.F. 2006. An impending water crisis in Canada's western prairie provinces. Proceedings of the National Academy of Sciences USA 103: 7210-7216.
Sinnatamby, R.N., Yi, Y., Sokal, M.A., Clogg-Wright, K.P., Asada, T., Vardy, S.H., Karst-Riddoch, T.L., Last, W.M., Johnston, J.W., Hall, R.I., Wolfe, B.B. and Edwards, T.W.D. 2010. Historical and paleolimnological evidence for expansion of Lake Athabasca (Canada) during the Little Ice Age. Journal of Paleolimnology 43: 705-717.
Wolfe, B.B., Hall, R.I., Edwards, T.W.D., Jarvis, S.R., Sinnatamby, R.N., Yi, Y. and Johnston, J.W. 2008. Climate-driven shifts in quantity and seasonality of river discharge over the past 1000 years from the hydrographic apex of North America. Geophysical Research Letters 35: 10.1029/2008GL036125.