Volcanic eruptions can have a major influence on the Earth system. Aerosols, gas molecules, and fine ash particles from large explosive eruptions can remain in the stratosphere for months to years, decreasing incoming solar radiation and causing Earth’s surface to cool. Eruption records reflect t... Show moreVolcanic eruptions can have a major influence on the Earth system. Aerosols, gas molecules, and fine ash particles from large explosive eruptions can remain in the stratosphere for months to years, decreasing incoming solar radiation and causing Earth’s surface to cool. Eruption records reflect temperature decreases significant enough to disrupt the water cycle and reduce atmospheric carbon dioxide concentrations. The impact of volcanic eruptions on ocean biogeochemistry has not been well studied, yet there is a pressing need to explore this topic because volcanic eruptions are analogous to radiation management geoengineering schemes and to the climate effects of a potential nuclear conflict. Understanding these effects may also help us understand the effects of past asteroid collisions with the Earth. Using output from the Community Earth System Model Large Ensemble (CESM-LE), which includes atmospheric and biogeochemistry components, we investigated the effects of three major volcanic eruptions in the past (Agung 1963, El Chichón 1982, Mount Pinatubo 1991) on the modeled ocean potential hydrogen (pH.) Ocean pH is a measure of ocean acidity that is closely tied to temperature, salinity, and carbon dioxide solubility in seawater. We show that sea surface temperatures decrease following a volcanic eruption (see figure below) and global ocean pH rises in the next two to three years. We further show this effect is amplified in the equatorial Pacific as a result of slower upwelling of corrosive water during an El Niño-like event, which supports current scientific discussion regarding El Niño-like responses following a volcanic eruption. Show less
