Abstract Summary
Historical temperature variability and past exposure to heat stress have been found in recent studies to be key factors contributing to coral reef resilience. With future heat stress predicted to become more frequent and severe, prioritizing sites with locally higher variability and lower warming trends in historical and predicted temperature may represent the greatest opportunity for success of coral reef restoration activities in the face of climate change. Understanding spatial patterns of thermal history can inform selection of sites for targeted restoration efforts. NOAA Coral Reef Watch (CRW) has recently updated its Thermal History product suite, extending the period for calculating metrics to 1985-2017 and transitioning the source data to use CRW’s CoralTemp dataset. CoralTemp is a global, daily, 0.05° (~5 km) gridded sea surface temperature (SST) product, which has an internally consistent baseline through the entire period and now underpins CRW’s near real-time decision support system for coral bleaching management. The updated Thermal History suite maintains the existing thematic groupings of Stress Frequency, Stress Onset, SST Variability, SST Trend, Climatology, and Annual History, with data and images provided at https://coralreefwatch.noaa.gov/satellite/thermal_history/. Augmenting historical variability, exposure and trends with downscaled future projections of heat stress (at ~4 km resolution, https://coralreefwatch.noaa.gov/climate/projections/downscaled_bleaching_4km/) further provides managers with information to support site selection for restoration efforts. Other physical and anthropogenic site characteristics, such as those recommended in guidance for assessing reef resilience (e.g., light stress, pollution, fishing pressure), will also help guide prioritization of restoration sites.
