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Source: IPCC Climate Change (2001) Synthesis Report Working Group 1, 11, 111 www.ipcc.ch.
Aerosols are shown on the climate forcing diagram above.
Climate forcings , or factors that push the climate to change, include both natural factors and human influences. Two key natural events and processes are the intensity of the sun reaching the earth and the concentration of volcanic dust that reflects light back into space. Both affect how much energy gets through to Earth’s atmosphere and how much of the energy is reflected back into space. See Albedo sections 3.2.6 and 3.3.1
Especially in industrialized areas, local air pollution gases and particles, and alterations of land use are contributing factors. Sooty aerosols have a warming effect. Sulphate aerosols have a cooling effect due to their atmospheric chemistry. See also winds and jet stream section 3.2.3.a, b
Natural aerosols generally cause a cooling effect.
Activity
- List the aerosols that have been introduced to the atmosphere by human activity using the IPPC chart above.
- Explain what the title of this diagram means. Why are the units used watts per square metre?
- What areas need the most research to increase the level of certainty?
Research
- Why do sulphates have a negative or cooling effect?