Fine-Grained Insolation Modulation.
We note technical possibilities of modulating insolation in a latitude-dependent manner. Consistent with the slow latitudinal mixing-time of the stratosphere well above the tropopause, different amounts of scattering material might be deployed(e.g., at middle stratospheric altitudes, ~25 km) at different latitudes, so as to vary the magnitude of insolation modulation for relatively narrow latitudinal bands around the Earth, e.g., to reduce heating of the tropics by preferential loading of the mid-stratospheric tropical reservoir with insolation scatterer.Indeed, scatterers of sunlight could be deployed at some latitudes to decrement insolation, while scatterers of Earth-emitted long-wavelength infrared radiation (which effectively increment insolation) could be deployed at other latitudes.
Differential cooling and heating, respectively, of underlying land-and-ocean latitudinal bands could thereby be accomplished. Furthermore, use of scatterers of varying stratospheric residence times to simultaneously modulate insolation and LWIR radiative losses in a specified latitude band might be employed to fine-tune, e.g., diurnal or seasonal temperature variability.
We have reviewed all the approaches known to us which appear to be of practical significance with respect to addressing the large-scale thermal effects of climate failure –both
global warming and Ice Ages – from the perspective of insolation modulation. In the course of this review, we have applied fundamental physical design principles to mass-optimize several previous proposals in order to enhance their practicality, and we have been able to remove more than an order-of-magnitude of superfluous mass from some earlier conceptual designs. Two insolation modulation systems which we have considered – quasi-resonant scatterers for intra-atmospheric applications and the small-angle-scattering system for deep space use – are apparently novel. These involve total system masses of the order of 10
tons – which is 2-5 orders of magnitude less mass than that of the most interesting previous proposals. We conclude that the insolation modulation approach to prevention of climate failure is certainly technically feasible-in-principle, and that the total costs-to-own its best examples may be