Exposure of marine protected areas to future ocean warming: Indices to guide climate adaptation planning

Climate change may undermine the values that marine protected areas (MPAs) are designed to conserve. Managers require an understanding of MPA climate-exposure to prioritise management actions. We present globally relevant indices for quantifying the exposure of MPAs to future ocean warming and discuss their implications for prioritising climate adaptation management actions using a network of marine parks on Australia's east coast as a case-study. Sea surface temperature (SST) data from a multi-model ensemble of downscaled climate models forced under SSP2-4.5 and SSP5-8.5 scenarios were used to quantify rates of warming and future timepoints that novel SST conditions are projected to emerge within MPAs. These measures were integrated using weighted sum models to calculate a novel 'index of relative exposure' used to rank marine parks by their exposure to future warming. Our findings reveal which marine parks are likely to be most exposed to future warming (i.e. Batemans Marine Park) and those that are less exposed and have potential to act as climate refugia (e.g. Port Stephens-Great Lakes Marine Park). We highlight the utility of this information for managers and policy makers considering nine key MPA climate change adaptation actions.