Isaksen, ISA; Granier, C; Myhre, G; Berntsen, T; Dalsøren, SB; Gauss, M; Klimont, Z; Benestad, R; Bousquet, P; Collins, W; Cox, T; Eyring, V; Fowler, D; Fuzzi, S; Jöckel, P; Laj, P; Lohmann, U; Maione, M; Monks, P; Prevot, ASH; Raes, F et al

Atmospheric Environment

Published date October 1, 2009

Atmospheric composition change: Climate–Chemistry interactions

  • States chemically active climate compounds are either primary compounds like methane (CH4), removed by oxidation in the atmosphere, or secondary compounds like ozone (O3), sulfate and organic aerosols, both formed and removed in the atmosphere
  • States man-induced climate–chemistry interaction is a two-way process: emissions of pollutants change the atmospheric composition contributing to climate change through the aforementioned climate components, and climate change, through changes in temperature, dynamics, the hydrological cycle, atmospheric stability, and biosphere-atmosphere interactions, affects the atmospheric composition and oxidation processes in the troposphere
  • States a key factor is the oxidation potential involving compounds like O3and the hydroxyl radical (OH)
  • Identifies several areas where climate change can affect the tropospheric oxidation process and the chemical composition:
    • enhanced stratospheric–tropospheric exchange of ozone
    • more frequent periods with stable conditions favoring pollution build up over industrial areas
    • enhanced temperature induced biogenic emissions
    • methane releases from permafrost thawing, and
    • enhanced concentration through reduced biospheric uptake
  • States emission scenarios for the coming decades have a large uncertainty range, in particular with respect to regional trends, leading to a significant uncertainty range in estimated regional composition changes and climate impact