Artificial Flooding Leads to Thicker and Brighter Arctic Sea Ice

[Geoengineering News]

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2025EF007894

Authors: Edward Blanchard-Wrigglesworth, Andrea Ceccolini, Andrew Smith, Andrew Woods, Cían Sherwin, Konrad Borowski, Pascal Martin-Daguet, Simon Woods, et al.

First published: 22 May 2026

https://doi.org/10.1029/2025EF007894Digital 

Abstract

We describe and present results from a 2024/2025 field campaign that is the first to test and observe the impact of flooding and meltwater draining on Arctic sea ice over the winter growth and spring melt seasons. The campaign was conducted in Cambridge Bay, Nunavut, Canada. A 1 by 1 km fieldwork site was used, comprising three control areas, which were never flooded, and eight test areas. In these, flooding treatments were carried out by pumping seawater onto the sea ice. Some test areas were flooded once (in December or January), while others were flooded twice (in December and February, or January and February). The total area flooded was 0.25 km2. Additionally, one control area was used for a melt pond drainage experiment during spring. By mid May, prior to melt, flooded test areas were up to 32 cm thicker than control areas, with snow cover that was 1–13 cm thinner. Areas flooded twice exhibited greater thickening than those flooded once. During the melt period, sea ice in the flooded areas appeared brighter and showed slower melt rates, remaining thicker than that in the control areas. The drained melt pond site also brightened markedly within 1 week of borehole drilling. Comparison with a historical sea ice thickness record from Cambridge Bay indicates that a 30 cm increase corresponds to roughly the magnitude of long-term thinning observed over the past 50 years.

Plain Language Summary

Arctic sea ice has been declining for the last few decades, and in the summer is expected to disappear by the middle of the century, causing further Arctic warming, coastal erosion, loss of wildlife, and impacting Arctic livelihoods. In response, several engineering approaches have been suggested to help slow down the loss of Arctic sea ice, such as stratospheric aerosol injection, surface albedo modification, or promoting sea ice thickening by flooding the surface with seawater during winter. This last idea has been tested in models, and here we document the first experiment to test it in the field with a small-scale (1 by 1 km) fieldwork campaign. Over the winter of 2024/2025, we flooded and monitored several test areas, while leaving control areas unaffected. We found that by the end of the winter sea ice growth season in mid-May, sea ice that had been flooded was up to 32 cm thicker than unflooded sea ice, equivalent to 50 years of thinning in the region. We also found that flooded sea ice was brighter during the melt season, leading to slower melt rates. In addition, a melt pond draining test in late May showed the surrounding area to effectively drain and brighten within days.

Source: AGU