Glacier geoengineering to address sea-level rise: A geotechnical approach

It is remarkable that the high-end sea level rise threat over the next few hundred years comes almost entirely from only a handful of ice streams and large glaciers. These occupy a few percent of ice sheets’ coastline. Accordingly, spatially limited interventions at source may provide globally-equitable mitigation from rising seas. Ice streams control draining of ice sheets; glacier retreat or acceleration serves to greatly increase potential sea level rise. While various climatic geoengineering approaches have been considered, serious consideration of geotechnical approaches has been limited – particularly regarding glaciers. This study summarises novel and extant geotechnical techniques for glacier restraint, identifying candidates for further research. These include draining or freezing the bed; altering surface albedo; creating obstacles: retaining snow; stiffening shear margins with ice; blocking warm sea water entry; thickening ice shelves (increasing buttressing, and strengthening fractured shelves against disintegration); as well as using regional climate engineering or local cloud seeding to cool the glacier or add snow. Not all of these ideas are judged reasonable or feasible, and even fewer are likely to be found to be advisable after further consideration. By describing and evaluating the potential and risks of a large menu of responses – even apparently hopeless ones – we can increase the chances of finding one that works in times of need.