Climate Change Induced Seasonal Amplification of the Indian Ocean CO2 Sink

Abstract

This study investigates changes in the mean and seasonal states of oceanic carbon uptake across the Indian Ocean (IO) using an improved, high‐resolution, observationally constrained long‐term (1980–2019) surface ocean pCO2 ${\text{pCO}}_{2}$ data product. The Arabian Sea shows a ∼14% decline in CO2 ${\text{CO}}_{2}$ flux amplitude along with reduced mean source strength. In contrast, the Equatorial IO exhibits the largest increase in seasonal amplitude (∼48%), followed by the Southern IO (∼23%), while the Bay of Bengal shows only a modest change (∼7%). Despite these differences, mean source strength decreases in both the Bay of Bengal and Equatorial IO, whereas the Southern IO shows an enhanced carbon sink. Amplitude changes in the Arabian Sea and Bay of Bengal are driven by shifts in flux sensitivity to wind speed and evolving seasonality of the ocean‐atmosphere pCO2 ${\text{pCO}}_{2}$ gradient, whereas in the Equatorial and Southern regions, they are primarily controlled by the evolving pCO2 ${\text{pCO}}_{2}$ gradient alone.