Aerosols and Climate

The chapter describes the important role aerosols may have played in the past and are still playing in today’s climate, discussing aerosol distribution, aerosol–climate interaction, aerosol–radiation interaction, aerosol–cloud interaction and aerosol–surface interaction. The biogeochemical aspects are illustrated using the CLAW hypothesis about feedback of dimethylsulphide on climate, and the role that volatile organic carbons may play in shaping today’s climate. Aerosol sources and sinks are shown and it is clear that a substantial part today originates from humans. The aerosols may interact with radiation through scattering and absorption and with clouds to change the availability of cloud condensation nuclei. The basic physics of these interactions are described. The role of volcanic explosions and dust is elucidated and, particularly, the role of dust and associated iron in glacial–interglacial transitions is discussed.