The most interesting application for climate geo-engineering might be to overcome the next ice age. Milankovich astronomical theory and also the experience of the last 2 million years suggest that the current interglacial period (Holocene) will soon come to an end and that the earth will soon enter into another glaciation.
Alarms of an imminent ice age have been raised from time to time, for example in the 1970s after a prolonged period of climate cooling, and even more recently as the climate cooled slightly in the past few years. One needs to distinguish, however, between a Little Ice Age that may be part of a more-or-less regular 1,500-year cycle (and likely related to solar activity) and a true ice age that relates to a change in solar irradiance brought about by changes in earth’s orbit, axis inclination and precession.
Not everyone agrees that such a Milankovich glaciation is imminent. For example, Andre Berger et al believe it might be as much as 40,000 years away. In any case, everyone agrees that a glaciation would bring about unprecedented hardship to the world, including crop failures, starvation – and wipe out much of the earth’s human population.
The accepted mechanism for the initiation for a glaciation is the survival of a snow field at high northern latitudes during the summer, with feedback (due to increased albedo and cooling) enlarging the snow and ice area gradually over the years to cover much of the Northern Hemisphere. This effect may be the ‘Achilles heel’ of glaciation. Can it be stopped before it spreads?
The geo-engineering task would consist of three phases: (1) a more detailed studied of the Milankovich glaciation mechanism; (2) setting up a protocol for satellite search for surviving snowfields; (3) field experiments with soot dispersal to decrease the albedo and cause the disappearance of snowfields so they absorb solar radiation instead of reflecting it.
1. A search of climate literature suggests that the sensitive region for initiation of an ice age is in the vicinity of 56 deg North latitude, which would place it into Canada, Scandinavia, or Siberia. The coldest areas in these regions are likely to be at the higher altitudes, which narrows the search to particular locations. Since the initiation mechanism depends on the survival of high-albedo snowfields throughout the whole summer, one can search existing data sources for such locations and define others where the duration of a high-albedo snowfield might extend well into the summer before melting. It may turn out that the initiation mechanism is more complicated and depends on being “kicked-off” by a century or even a decades-long period (like a Little Ice Age) -- or perhaps even by a major volcanic eruption like the one that led to the very cold summer of 1816 – that promotes the survival of the initiating snowfield.
2. Once the likely locations are defined, one can set up a protocol whereby weather satellites can routinely observe and track the albedo in these regions, locate snow fields that survive during the summer and expand from year to year -- and alert decision makers on the possibility of an ice-age initiation. This task seems fairly routine and could be initiated with existing resources.
3. Finally one would like to demonstrate the feasibility of artificially melting and removing a snowfield. This task would investigate the technical resources needed and define the details and costs of such an operation. One possibility that comes to mind will be to use “crop-duster” planes to distribute soot material over the snow field and observe the rate of melting, comparing it to what would be expected from theory. Such field experiments could be usefully conducted while the other parts of the project are proceeding.
The end result would be to demonstrate a reliable means of overcoming the initiation of a future ice age. The geo-engineering operation of removing the high-albedo snow fields might have to be done year after year until the astronomical conditions change sufficiently so that the sun itself could operate to remove the possibility of an ice age.
S. Fred Singer, PhD, President of Science & Environmental Policy Project Dr. Singer can be reached at: comments@sepp.org 
