Coral Reef Exposure to Damaging Tropical Cyclone Waves in a Warming Climate

Abstract

Tropical cyclones generate large waves that physically damage coral communities and are commonly cited as a worsening threat to coral reefs under climate change. However, beyond projections of ocean basin‐scale changes in cyclone intensity, the other determinants of future coral reef damage such as cyclone size and duration remain uncertain. Here, we determine the extent to which downscaled cyclones represent observed cyclone characteristics that influence wave damage to Australian coral reef regions. We then investigate mid‐century (2040–2060) and end of century (2080–2100) downscaled tracks to assess whether cyclone characteristics will change with future warming under a high‐emissions scenario. We find that spatial uncertainties in downscaled cyclogenesis and track positions limit estimates of reef damage for individual coral reefs and regions. Further, the models are unable to reproduce the most reef damaging cyclones for any of the regions. The downscaled tracks capture observed cyclone characteristics, such as size, impacting the Great Barrier Reef well, but perform poorly for the Northern Territory, with mixed performance for the Coral Sea and Western Australia. We find no clear evidence that cyclones will cause more damage to Australian coral reef regions in the future, at least based on the climate models and downscaling approach examined here. There is increasing interest in using tropical cyclone projections to assess future coral reef exposure to damaging waves. We recommend caution when interpreting such projections due to large uncertainty in the mechanisms that influence reef damaging tropical cyclone characteristics and how these will change with future warming.

Protecting Great Barrier Reef resilience through effective management of crown-of-thorns starfish outbreaks

“…As the only major driver of coral mortality on the GBR that is amenable to direct local action [ 14 ], COTS control currently provides the only effective tool for coral preservation deployable at scale [ 37 , 65 ]. With the predicted increase in frequency and severity of coral bleaching [ 66 , 67 ] and ongoing severe tropical cyclones [ 68 , 69 ], the persistence of a coral dominated GBR will crucially rely on offsetting mortality from these and other disturbance events when possible. While emerging methodologies for coral restoration [ 70 ] assisted evolution [ 71 , 72 ] are encouraging, they remain cost prohibitive at large scales [ 73 ], and the most effective way to protect corals is to, quite simply, prevent mortality in the first place [ 74 ].…”

Coral reef fish resilience and recovery following major environmental disturbances caused by cyclones and coral bleaching: A case study at Lizard Island

“…If corals are not recolonised by Zooxanthella, they are predicted to die within approximately six months (McCook, 2002). In addition to extreme climatic events causing bleaching, cyclones are also an imminent threat to corals and can cause significant coral cover loss in exposed areas (Cheal et al, 2017; Dixon et al, 2022).…”

Combined Role of the MJO and ENSO in Shaping Extreme Warming Patterns and Coral Bleaching Risk in the Great Barrier Reef

“…Conversely, coral bleaching risk tends to be reduced during periods of storms or high rainfall, as increased cloud cover can act to decrease sea surface temperatures (Hughes et al, 2017;Zhao et al, 2021) and strong winds increases evaporative cooling and mixing of warmer surface waters with cooler deep waters (MacKellar and McGowan, 2010;Yee and Barron, 2010). The passage of tropical cyclones can also reduce ocean temperatures across broad spatial scales, potentially mitigating mass coral bleaching events (Carrigan and Puotinen, 2014), although they may instead cause physical damage to coral reefs (Harmelin-Vivien, 1994;Dixon et al, 2022). Therefore, understanding the drivers of atmospheric variability over the GBR can inform potential predictability of bleaching events, which is essential for effective coral reef conservation and management (Smith and Spillman, 2019).…”