3.5: Other kinds of interventions
Outside of targeting CO2 removal or solar radiation management per se, one could in theory make more local, or more effect-specific, modifications to major climate processes.
Countering sea level rise directly
Freeman Dyson proposed, as a zany conceptual sketch illustrating a space of possibility, kites or balloons to modify the air flow over the coast of East Antarctica — to dump more snow on comparatively-stable East Antarctica, potentially sucking out from the ocean sea water released by melting of Greenland and/or West Antarctica, and thus lowering sea levels:
Or more briefly, if Greenland and West Antarctica completely melt this could lead to a 15m sea level rise which would be terrible. East Antarctica is not in danger of melting and we could try moving the current anticyclone that is over this region towards West Antarctica. The could be done with a giant series of kits along one side of this anticyclone which would push it towards West Antarctica which would suck up more moist air and create snowfall over East Antarctica. This could counteract sea level rises due to West Antarctica and Greenland melting.
“Snow-dumping in East Antarctica would be a good way to stop sea levels from rising. Sea levels have been rising since the end of the most recent ice age 12,000 years ago. Most of the rise had nothing to do with human activities, but a further catastrophic rise by fifteen meters is a possible worst-case consequence of human activities in the next two centuries. A fifteen-meter rise would be the result of a complete meltdown of the ice in Greenland and West Antarctica caused by global warming. Such a meltdown is unlikely but not impossible. Fortunately, East Antarctica is much colder and larger than Greenland and West Antarctica, and the ice cap on East Antarctica is not in danger of melting. A permanent high-pressure anticyclone over East Antarctica keeps the air over the continent dry and the snowfall meager. The same anticyclone keeps a strong westerly flow of moist air circling around the southern ocean… To dump snow onto East Antarctica, we must move the center of the anticyclone from the center to the edge of the continent. This could be done by deploying a giant array of tethered kites or balloons so as to block the westerly flow on one side only. The blockage would cause a local rise of atmospheric pressure. The center of the anticyclone would move toward the blockage, and a fraction of the circulating westerly winds on the opposite side of Antarctica would move from the ocean onto the continent. The kites or balloons might also be used to generate massive quantities of electric power for use in other projects of planetary engineering. With or without electric generators, the onshore flow of moist air at a rate of a few kilometers per hour would produce an average snowfall equivalent to a few meters of ice per year over East Antarctica. All the ice added to the continent would be subtracted from the ocean. This would be enough snowfall to counteract the sea-level rise produced by a complete meltdown of Greenland and West Antarctica in two hundred years. Year by year, we could raise or lower the kites and adjust the flow of moist air across the continent so as to hold sea levels accurately constant.”
There is a sketch of a related idea for the Arctic, where the situation by some assessments doesn’t look good — here the idea is to reduce the ice melt itself, whereas in Dyson’s idea, you would be lowering sea levels even if the ice had already melted, and regardless of the cause of that melt (as long as East Antarctica is still available as a snow dumping site). Methods for increasing ice reflectivity, e.g., with coatings of glass microspheres, have also been suggested, as has localized albedo change to the Arctic ocean.
Different major Arctic and Antarctic bodies of sea ice are melting via different processes and due to different proximal causes, and would theoretically require different types of interventions to mitigate their ice loss. An interesting aspect for the Arctic is the ice albedo, and the effect of pollution on that, as opposed to global warming per se
This article covers three potential ways to reduce glacial melting, including a) blocking warm water, b) supporting ice shelves, and c) drying subglacial streams. As the authors state:
“Even if greenhouse-gas emissions are slashed, which looks unlikely, it would take decades for the climate to stabilize… Geoengineering of glaciers will not mitigate global warming from greenhouse gases. The fate of the ice sheets will depend on how quickly we can reduce emissions. If emissions peak soon, it should be possible to preserve the ice sheets until they are again viable. If they keep rising, the aim will be to manage the collapse of the ice sheets to smooth the rate of sea-level rise and ease adaptation.”
Here is a peer-reviewed paper on the idea of supporting the West Antarctic ice, and a diagram from it: