Future Changes in δ 13 C of Dissolved Inorganic Carbon in the Ocean

Emissions of carbon dioxide from fossil fuel combustion are reducing the ratio 13C/12C, δ13C, in atmospheric CO2 and ocean terrestrial biosphere that exchanges with atmosphere on timescales decades to centuries. Future changes emissions vary across different scenarios may cause decreases more than 6% δ13CO2 between 1850 2100. The effects these potential three-dimensional distribution δ13C have not yet been investigated. Here, we use an biogeochemical-circulation model forced a range Shared Socioeconomic Pathway (SSP)-based simulate dissolved inorganic In future, vertical horizontal gradients characteristic biological pump reduced or reversed, relative preindustrial period, reversal occurring higher emission scenarios. For highest scenario, SSP5-8.5, surface center Pacific subtropical gyres falls 2.2% −3.5% by lower scenarios, but then rebounds. relationship anthropogenic (Cant) shows larger scatter all suggesting uncertainties δ13C-based estimates Cant increase future. These simulations were run fixed physical forcing circulation, providing baseline predicted δ13C. Further work is needed investigate impact climate-carbon cycle feedbacks changes.