December 31, 2009 – Original Source: Science Daily
As the Arctic warms, permafrost will degrade, potentially resulting in increased groundwater runoff as frozen ground that had blocked the flow of water melts. To investigate how groundwater systems will evolve as surface temperatures rise, Bense et al. developed a model to simulate an idealized aquifer covered by a layer of permafrost.
They ran the simulation under three scenarios, starting with three initial surface temperatures (-2, -1.5, and -1 degrees Celsius, or 28.4, 29.3 and 30.2 degrees Fahrenheit), corresponding to different permafrost thicknesses. In each case, they increased the average seasonal surface temperature by 3 degrees C (5.4 degrees F) over 100 years, an average of model predictions for temperature increase in the Arctic over the next century.
After the warming period, in each scenario the temperature was then held constant for the next 1100 years.
The authors found that although the initial distribution of ice influences the response, in all cases groundwater flow to streams and rivers accelerates over time. In fact, the results indicate that substantial increases in groundwater flow are likely over the next few centuries even if surface air temperatures stabilize at current levels.
The research is published in Geophysical Research Letters. Authors include V. F. Bense: School of Environmental Sciences, University of East Anglia, Norwich, UK; G. Ferguson: Department of Earth Sciences, Saint Francis Xavier University, Antigonish, Nova Scotia, Canada; H. Kooi: Faculty of Earth and Life Sciences, VU University, Amsterdam, Netherlands.
- Bense et al. Evolution of shallow groundwater flow systems in areas of degrading permafrost. Geophysical Research Letters, 2009; 36 (22): L22401 DOI: 10.1029/2009GL039225