Ocean Acidification

Ocean uptake of anthropogenic CO2 causes a decline in seawater pH, a process known as ocean acidification, which may adversely affect marine organisms. We investigate whether continental weathering can mitigate future ocean acidification by sequestering atmospheric CO2. We conducted simulations under a suite of carbon emission scenarios with different weathering parameterizations. The short-term impact of a strong weathering feedback was only notable for large emissions with slow injection. This mitigation by enhanced weathering, however, is an order of magnitude smaller than the expected maximum pH decline based on the default parameterizations. Thus on short timescales, weathering has little effect on future atmospheric CO2 and ocean acidification, regardless of the assumed weathering feedback strength. But on longer timescales and for large emissions, different weathering parameterizations introduce large uncertainties regarding the time when pCO2 will return to climatically relevant levels of, say, 400 μatm in the future.



Uchikawa, J., and R. E. Zeebe, 2008. Influence of terrestrial weathering on ocean acidification and the next glacial inception, Geophysical Research Letters 35:L23608. Article.