Artificial Upwelling - a refined narrative

The current narrative of artificial upwelling (AU) is to translocate nutrient rich deep water to the ocean surface, thereby stimulating the biological carbon pump (BCP). Our refined narrative takes the response of the solubility pump and the CO2 emission scenario into account. Using global ocean-atmosphere model experiments we show that the effectiveness of a hypothetical maximum AU deployment in all ocean areas where AU is predicted to lower surface pCO2, the draw down of CO2 from the atmosphere during years 2020–2100 depends strongly on the CO2 emission scenario and ranges from 1.01 Pg C/year (3.70 Pg CO2/year) under RCP 8.5 to 0.32 Pg C/year (1.17 Pg CO2/year) under RCP 2.6. The solubility pump becomes equally effective compared to the BCP under the highest emission scenario (RCP 8.5), but responds with CO2 outgassing under low CO2 emission scenarios. Key Points: - Artificial upwelling (AU) effectiveness to draw down CO2 from the atmosphere is strongly dependent on the future CO2 emission scenario - The solubility pump becomes as effective as the biological carbon pump under high emission scenarios - Organic matter transfer efficiency decreases under AU, likely due to higher water temperatures below the ocean's surface