Threat by marine heatwaves to adaptive large marine ecosystems in an eddy-resolving model
Xiuwen Guo, Yang Gao, Shaoqing Zhang, Lixin Wu, Ping Chang, Wenju Cai, Jakob Zscheischler, L. Ruby Leung, Justin Small, Gökhan Danabasoglu, LuAnne Thompson, Huiwang Gao
Abstract
Marine heatwaves (MHWs), episodic periods of abnormally high sea surface temperature (SST), severely affect marine ecosystems. Large Marine Ecosystems (LMEs) cover ~22% of the global ocean but account for 95% of global fisheries catches. Yet how climate change affects MHWs over LMEs remains unknown, because such LMEs are confined to the coast where low-resolution climate models are known to have biases. Here, using a high-resolution Earth system model and applying a "future threshold" that considers MHWs as anomalous warming above the long-term mean warming of SSTs, we find that future intensity and annual days of MHWs over majority of the LMEs remain higher than in the present-day climate. Better resolution of ocean mesoscale eddies enables simulation of more realistic MHWs than low-resolution models. These increases in MHWs under global warming poses a serious threat to LMEs, even if resident organisms could adapt fully to the long-term mean warming.