ISSN 0001-4338, Izvestiya, Atmospheric and Oceanic Physics, 2011, Vol. 47, No. 4, pp. 430–438. © Pleiades Publishing, Ltd., 2011. Original Russian Text © E.M. Volodin, S.V. Kostrykin, A.G. Ryaboshapko, 2011, published in Izvestiya AN. Fizika Atmosfery i Okeana, 2011, Vol. 47, No. 4, pp. 467–476. 430 1. INTRODUCTION In recent years there has been a resurgence of inter- est in the development of unconventional measures to stabilize the Earth’s climate (geoengineering), among which the stratospheric injection of sulfur compounds resulting in the formation of aerosol is considered to be one of the most promising methods [1]. The con- clusion about the benefits of using such methods can certainly be made only on the basis of a complex assessment of the consequences of geoengineering. A number of papers are therefore devoted to mathemat- ically modeling the consequences of geoengineering. Models of intermediate complexity [2, 3], as well as atmosphere–ocean general circulation models, including atmosphere–ocean general circulation and atmospheric chemistry [4, 5], are used for their assess- ment. The results of studies on the simulation of geongineering were summarized in [1]. The distinc- tion of the given paper from those listed above is, firstly, an investigation of the effectiveness of the geoengineering approach depending on the latitude and longitude of injection of sulfur compounds. Sec- ondly, the given paper most fully treats the variety of factors that influence or depend on the simulated geoengineering, including the transport and chemical conversions of sulfur compounds resulting in the for- mation of aerosol, atmosphere–ocean general circu- lation, the carbon cycle, and atmospheric chemistry. 2. DESCRIPTION OF THE MODEL AND NUMERICAL EXPERIMENTS A model of the Earth’s system that included the atmospheric dynamics, the ocean dynamics, atmo- spheric chemistry, and the carbon cycle was used to perform a series of numerical experiments to investi- gate the effectiveness of geoengineering depending on the altitude and latitude of injection [6]. In the atmo- sphere, the model has a resolution of 5° by 4° in longi- tude and latitude and 39 levels extending to 90 km. In the ocean the resolution is 1° by 0.5° in longitude and latitude with 40 levels vertically. The model includes a module of atmospheric chemistry [7]. The influence that the geoengineered sulfate aerosol has on atmospheric chemistry is taken into account through a prescribed surface area of aero- sol particles. It is assumed that the aerosol itself does not participate in chemical reactions, but some reac- tions of the chlorine and bromine cycles, which, in particular, ultimately change the ozone concentra- tion, can proceed on its surface. The model also includes a calculation of compo- nents of the carbon cycle in accordance with [8], although the concentration of carbon dioxide in the atmosphere was prescribed. The atmospheric model is supplemented by a sulfur scheme describing the transport and physicochemical conversions of four substances: H 2 S, SO 2 , H 2 SO 4 , and Simulation of Climate Change Induced by Injection of Sulfur Compounds into the Stratosphere E. M. Volodin a , S. V. Kostrykin a , and A. G. Ryaboshapko b a Institute of Numerical Mathematics, Russian Academy of Sciences, ul. Gubkina 8, Moscow, 119991 Russia e-mail: volodin@inm.ras.ru b Institute of Global Climate and Ecology, Roshydromet, Russian Academy of Sciences, ul. Glebovskaya 20b, Moscow, 107258 Russia e-mail: agryaboshapko@mail.ru Received February 17, 2010; in final form, February 24, 2011 Abstract—An atmosphere–ocean general circulation model including the atmospheric chemistry and car- bon cycle was used to perform numerical experiments to simulate the consequences of geoengineering. Out of the five emission scenarios considered here, the scenario where the injection of sulfur compounds occurs near the equator at an altitude between 22 and 24 km can be considered the most efficient in the sense of a maximum decrease in globally averaged surface temperature. We consider the equilibrium distribution of the sulfate aerosol and changes in temperature at the Earth’s surface and at different altitudes, in precipitation, in ozone concentration, and in primary plant productivity caused by geoengineering. Keywords: climate change, geoengineering, aerosol, stratosphere, precipitation, ozone. DOI: 10.1134/S0001433811040116