The impact of Pinatubo on tropospheric chemistry and climate

Narcisa Banda

Methane (CH4) is the second most abundant anthropogenic greenhouse gas in the atmosphere after CO2. The evolution of its concentration in the past decades is not well understood. Particularly after the eruption of Mt. Pinatubo in 1991, large variations in the methane growth rate were observed. The eruption affected the global atmospheric composition and climate. SO2 injected in the stratosphere formed aerosols, which blocked the solar radiation. Stratospheric ozone was depleted by heterogeneous reactions on the sulphate aerosols. These changes in the stratosphere altered the amount of UV radiation reaching the troposphere, causing changes in photochemistry. Cooler temperatures after the eruption affected natural methane emissions from wetlands. Using the global chemistry model TM5, and the climate model EC-Earth, we aim to get a better understanding of the methane budget in the years following the Pinatubo eruption.