Intensifying Heat Stresses in Marine Protected Areas

Marine Protected Areas (MPAs) are vital for preserving marine biodiversity and supporting sustainable resource management. However, the intensifying impacts of future temperature extremes, such as marine heatwaves (MHWs), pose significant risks to marine ecosystems. This study utilizes high-resolution climate projections under the SSP585 scenario (AWI-CM3) to examine 21^st century changes in MHWs, defined as extreme deviations from the seasonally varying long-term temperature trend, within global MPAs, focusing on the surface to a depth of 300 meters. Our findings reveal that, while the frequency of MHWs is expected to decline, their intensity and duration are projected to increase, exacerbating accumulative impacts. On average, accumulative intensity is anticipated to rise by approximately 30 %, surpassing the global average increase of 25%. Notably, substantial increases are identified in mid- and high-latitude MPAs below the surface, while in the surface layer, such increases are observed in tropical MPAs. These results highlight the urgent need to understand how marine organisms and habitats will adapt to escalating heat stresses. Such insights are critical for ensuring the resilience and sustainability of marine ecosystems in the face of future climate challenges.