Significant Reduction of Potential Exposure to Extreme Marine Heatwaves by Achieving Carbon Neutrality

Abstract

Abstract Marine heatwave (MHW), a prolonged period of anomalously warm seawater, has a catastrophic repercussion on marine ecosystems. With global warming, MHWs have become increasingly frequent, intense, and prolonged. To avoid irreversible damages from such extreme events, net‐zero carbon emissions by the 2050s, called carbon neutrality, were proposed. Here, we evaluate the impact of carbon neutrality on MHWs in the late 21st century using multi‐model projections from the Coupled Model Intercomparison Project Phase 6 (CMIP6) Shared Socioeconomic Pathway (SSP) 1–1.9 and SSP3‐7.0 scenarios. It is found that if the current regional rivalry over carbon emissions continues (i.e., SSP3‐7.0), the MHWs in the late 21st century will become stronger and longer than historical ones, especially in the western boundary current and equatorial current regions. Approximately 68% of the global ocean will be exposed to permanent MHWs, regionally 93% in the Indian Ocean, 76% in the Pacific Ocean, 68% in the Atlantic Ocean, 65% in the Coastal Ocean, and 48% in the Southern Ocean. Such MHWs can be significantly reduced by achieving carbon neutrality (i.e., SSP1‐1.9). In particular, the spatial proportion of the ocean exposed to permanent MHWs can be reduced to as low as 0.02%–0.07%, depending on the regions. This result underscores the critical importance of ongoing efforts to achieve net‐zero carbon emissions to reduce the potential ecological risks induced by extreme MHWs.

Keywords

• marine heatwaves
• carbon neutrality
• exposure
• reduction
• SSP1‐1.9
• CMIP6