Why aerosols are important in climate change monitoring
Considerable research is being undertaken to understand the impact that aerosols have in the global radiation balance. Radiative forcing is defined as the “change in net irradiance at the tropopause after allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values.” (IPCC, 2007).
In other words, radiative forcing is the imbalance between incoming solar radiation and outgoing infrared radiation which causes a change in the Earth’s radiative balance. This imbalance causes changes in global temperatures. The IPCC report suggests a linear relationship between the global mean equilibrium surface temperature changes and the amount of radiative forcing.
Aerosols impact on radiative forcing is still not fully understood due to a variety of reasons including the dynamic nature and short life of aerosols in the atmosphere. Aerosols have both a direct impact on incoming radiation by scattering and absorbing solar and thermal radiation and also an indirect effect through cloud development, cloud albedo changes and precipitation occurrence (Ghan S.J & Schwartz, S.E).