Global Warming has Increased the Distance Traveled by Marine Heatwaves
Study key findings & significance
- The frequency of marine heat waves (MHWs) showed an insignificant trend, and the duration, intensity, area and moving distance increased greatly over 1982–2020
- The strongest MHWs (more than the 80th percentile) have the largest increase in moving distance
- The extreme MHW category dominates the increase in projection/total area due to the rising moving distance
Due to the destructive effects of marine heatwaves (MHWs) on marine ecosystems and local economies, whether they become more frequent and stronger under global warming has attracted much attention. The proposed event-based algorithm identifies 3,843 MHWs during 1982–2020. Except for the MHW frequency, the global averaged duration, intensity, area and moving distance increased significantly. The contributions of the frequency and mean projection area to the total projection area were further investigated from the four categories of MHWs. The results showed that for moderate MHWs, frequency contributes more than the mean projection area to the increase in projection area; however, for strong, severe, and extreme MHWs, the mean projection area contributes much more than frequency. Due to the increased moving distance, the projected area change of the extreme MHW dominates the increase in the total projected area. The high sensitivity of extreme MHWs to global warming deserves extra attention.