Journal Article

Observed Regional Impacts of Marine Heatwaves on Sea‐Air CO2 Exchange

Burger, Friedrich A, Li, Catherine, Frölicher, Thomas L, Raible, Christoph C

2024

Overview

Marine heatwaves (MHWs) have devastating effects on ecosystems. Yet a global assessment of the regional impacts of MHWs on the sea‐air CO2 ${\\text{CO}}_{2}$ exchange is missing. Here, we analyze 30 global observation‐based sea‐air CO2 ${\\text{CO}}_{2}$ flux data sets from 1990 to 2019. Globally, the oceanic CO2 ${\\text{CO}}_{2}$ uptake is reduced by 8% (3%–19% across data sets) during MHWs. Regionally, the equatorial Pacific experiences a 31% (3%–49%) reduction in CO2 ${\\text{CO}}_{2}$ release and MHWs often coincide with extreme sea‐air CO2 ${\\text{CO}}_{2}$ flux anomalies in this region. The oceanic CO2 ${\\text{CO}}_{2}$ uptake decreases during MHWs by 29% (19%–37%) and 14% (5%–21%) in the low‐to‐mid latitude Northern and Southern Hemisphere, respectively. Reduced dissolved inorganic carbon in the tropics weakens outgassing, while high ocean temperatures diminish uptake in the low‐to‐mid latitudes. In the subpolar North Pacific and Southern Ocean, enhanced carbon uptake occurs during MHWs, but uncertainties in pCO2 ${\\text{CO}}_{2}$ data sets limit a comprehensive assessment in these regions.

• Publisher: John Wiley & Sons, Inc
• Subject: Air / Anomalies / Atmosphere / Carbon dioxide / Carbon dioxide exchange / Carbon uptake / Datasets / Dissolved inorganic carbon / Equatorial regions / Exchanging / Heat waves / Latitude / Marine ecosystems / Marine heatwaves / Ocean temperature / Oceans / Outgassing / Regional analysis / Regions / Sea surface temperature / Southern Hemisphere / Surface temperature / Temporal variations / Tropical environment / Tropical environments