GLOBAL WARMING AND ICE AGES: I. Prospects For Physics-Based Modulation Of Global Change*

It has been suggested that large-scale climate changes, mostly due to atmospheric injection of "greenhouse gases" connected with fossil-fired energy production, should be forestalled by internationally-agreed reductions in, e.g., electricity generation. The potential economic impacts of such limitations are obviously large: ≥$1011/year. We propose that for far smaller — <1% — costs, the mean thermal effects of "greenhouse gases" may be obviated in any of several distinct ways, some of them novel. These suggestions are all based on scatterers that prevent a small fraction of solar radiation from reaching all or part of the Earth. We propose research directed to quite near-term realization of one or more of these inexpensive approaches to cancel the effects of the "greenhouse gas" injection. While the magnitude of the climatic impact of "greenhouse gases" is currently uncertain, the prospect of severe failure of the climate, for instance at the onset of the next Ice Age, is undeniable. The proposals in this paper may lead to quite practical methods to reduce or eliminate all climate