A study reveals that sea otter recovery has helped buffer century-scale declines in California's kelp forests. Historical kelp canopy surveys from 1910–1912 showed coverage of about 120.4 km², slightly higher than the 112.0 km² recorded in 2014–2016. However, regional variations were significant, with increases in central California (+57.6%) and losses along the northern (-63.0%) and southern (-52.1%) coasts. Random Forest models identified sea otter population density as the primary driver of kelp changes, alongside benthic substrate, extreme heat, and primary productivity. The study highlights the importance of sea otters in maintaining kelp forest resilience. It also shows that kelp carbon storage may have increased by 5.3% over the last century, despite overall canopy decline. The research underscores the need for nature-based solutions to enhance coastal resilience to climate change. The findings suggest that restoring trophic relationships and minimizing coastal development stressors can improve kelp forest resilience in a warming climate. The study emphasizes the importance of long-term ecological records for understanding ecosystem dynamics and effective restoration. The results highlight the critical role of sea otters in maintaining kelp forest health and the need for conservation efforts to protect these ecosystems. The study also points to the potential of trophic rewilding to support natural climate resilience and carbon storage. The research underscores the importance of integrating kelp forests into blue carbon initiatives to enhance biodiversity, build natural climate resilience, and store carbon. The study provides a blueprint for nature-based solutions to address climate change and protect coastal ecosystems.A study reveals that sea otter recovery has helped buffer century-scale declines in California's kelp forests. Historical kelp canopy surveys from 1910–1912 showed coverage of about 120.4 km², slightly higher than the 112.0 km² recorded in 2014–2016. However, regional variations were significant, with increases in central California (+57.6%) and losses along the northern (-63.0%) and southern (-52.1%) coasts. Random Forest models identified sea otter population density as the primary driver of kelp changes, alongside benthic substrate, extreme heat, and primary productivity. The study highlights the importance of sea otters in maintaining kelp forest resilience. It also shows that kelp carbon storage may have increased by 5.3% over the last century, despite overall canopy decline. The research underscores the need for nature-based solutions to enhance coastal resilience to climate change. The findings suggest that restoring trophic relationships and minimizing coastal development stressors can improve kelp forest resilience in a warming climate. The study emphasizes the importance of long-term ecological records for understanding ecosystem dynamics and effective restoration. The results highlight the critical role of sea otters in maintaining kelp forest health and the need for conservation efforts to protect these ecosystems. The study also points to the potential of trophic rewilding to support natural climate resilience and carbon storage. The research underscores the importance of integrating kelp forests into blue carbon initiatives to enhance biodiversity, build natural climate resilience, and store carbon. The study provides a blueprint for nature-based solutions to address climate change and protect coastal ecosystems.