Geoengineering our future climate What is geoengineering? . The intentional large-scale manipulation of the environment intended to reduce undesired anthropogenic climate change · Has to be intentional · Has to be large scale . It is a relatively new field 2 types of approaches · Solar Radiation Management - intervenes in SW radiation system - aims to increase the reflectivity of the earth's surface so less shortwave radiation is absorbed · Carbon Dioxide Removal - intervenes in LW radiation system - aims to reduce the amount of CO2 in the atmosphere Solar Radiation Management techniques Stratospheric sulphate aerosols · Aims to mimic the effect of volcanoes (causes a rapid decrease in temperature for a few years) . One strategy is to attach on the back of planes something that will eject aerosols that will reflect back the SW radiation from the sun · Railguns can project ballistics into the upper atmosphere that will explode and release aerosols in the stratosphere · There has been no practical experiments to test this technology Solar "sunshade" (mirror in space) . We put up in Earth's orbit a big reflector that will reflect back the sunlight and decreases the intensity of radiation reaching the top of our atmosphere . There is a Lagrange (?) point which always lays between Earth and the sun . This scheme would take about 25 years and cost a few trillion dollars - feasible . We have to create a world similar to one half a billion years ago where the solar constant was weaker Cloud seeding . Clouds are important in the way they reflect radiation . Cloud seeding can create more clouds/make the clouds we have more reflective . You need the presence of cloud condensation nuclei . One solution is to find a mechanism to eject sea spray aerosols (directly from the sea) into the atmosphere we would create more clouds Crop albedo geoengineering . There is a huge area on the earth's surface that is dedicated to crops and agriculture - they are quite reflective already . We could modify the crops that we grow through genetic engineering to become brighter and more reflective
. The early stages of research have already started in this field . Could cause a 1°C cooling with a 10% change . Crops induced cooling is most significant in the areas with thin sea ice as the ice will not melt and will instead continue to be reflective Desert albedo geoengineering · The desert regions have a high albedo - can make it even higher by putting out huge highly reflective metallic sheets that would reflect back the incoming solar radiation . This could be very effective within the desert regions themselves and globally also . However, this would also cause a decrease in precipitation and the effect of monsoons in the desert regions Urban albedo geoengineering . Basically painting the roofs of newly constructed buildings white in order to increase the albedo of urban areas . This is being