Liévanos et al., 2019; Schwieterman et al., 2019). Warming and hypoxia are mostly positively correlated and tolerances to both phenomena are often linked after long-term acclimation . Acute short-term heat shocks can impair hypoxia tolerance, for instance, in intertidal fish . This is relevant for shallow waters, specifically for MHWs . Ocean acidification can increase hypoxia tolerance in some cases, possibly by downregulating activity  and/or changing blood oxygenation . Other studies, however, reported additive negative effects of acidification and warming on hypoxia tolerance , in line with the oxygen- and capacity-limited thermal tolerance  hypothesis presented in AR5 : Warming causes increased metabolic rates and oxygen demand in ectotherms, which at some point exceed supply capacities  and reduce aerobic scope. In consequence, expansion of OMZs and other regions where warming, hypoxia and acidification combine will further reduce habitat for many fish and invertebrates  .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report