An L1 positioned dust cloud as an effective method of space-based geoengineering

In this paper a method of geoengineering is proposed involving clouds of dust placed in the vicinity of the L1 point as an alternative to the use of thin film reflectors. The aim of this scheme is to reduce the manufacturing requirement for space-based geoengineering. It has been concluded that the mass requirement for a cloud placed at the classical L1 point, to create an average solar insolation reduction of 1.7%, is 2.93x109 kg yr-1 whilst a cloud placed at a displaced equilibrium point created by the inclusion of the effect of solar radiation pressure is 8.87x108 kg yr-1. These mass ejection rates are considerably less than the mass required in other unprocessed dust cloud methods proposed and, for a geoengineering period of 10 years, they are comparable to thin film reflector geoengineering requirements. It is envisaged that the required mass of dust can be extracted from captured near Earth asteroids, whilst stabilised in the required position using the impulse provided by solar collectors or mass drivers used to eject material from the asteroid surface.