Revistes Catalanes amb Accés Obert (RACO)

Mar de núvols. Oceans, aerosols, núvols i canvi climàtic

Rafel Simó

Resum


Earth climate is closely linked to the chemistry of the atmosphere through the influence of the latter on the radiative balance. Greenhouse gases and aerosols cause heat retention at the earth surface and the lower atmosphere, and aerosols and clouds affect the atmospheric albedo (i.e., the amount of solar radiation that is reflected back to space and never reaches the surface). Aerosols, hence, play a multiple role in regulating climate, either by their optical properties or by seeding cloud formation. There are many sources of aerosols, but over the remote ocean, far from continents, most come from the oxidation of sulphur, carbon, nitrogen, and iodine gases emitted by the oceans’ microbiota. Since the industrial revolution, aerosols have been playing a significant role in slowing down global warming. Over the current century, the oceans are predicted to reduce their cooling capabilities by sequestering less CO2 and increasing too little their emission of aerosols and cloud precursors. Together with the expected reduction of anthropogenic aerosol loads due to the development of cleaner combustion technologies, these effects are predicted to accelerate temperature rise unless greenhouse gas emissions are dramatically reduced.

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