CLEX’s world-leading research in Oceans Extremes, particularly around marine heatwaves, explains why this research program has come into being as a standalone area of investigation amidst the rearrangement of the CLEX research programs.

Recent research by our team has looked at how climate change will affect marine heatwaves around Australia and New Zealand. Changes to marine heatwaves have primarily been investigated in coarse-resolution climate models that are unable to resolve important ocean processes. For this study CLEX researchers used a high‐resolution climate model to investigate how and why marine heatwaves would change for the Australian region. The relative impacts of increases on background ocean temperature and changes to intrinsic temperature variations were compared. Variability changes were found to be most prominent close to Tasmania, linked to a strong future intensification of the East Australia Current. Waters around New Zealand were also affected, with this shift linked to changes in heat fluxes from the atmosphere. These results highlight the indirect impacts of future temperature increases on marine heatwave characteristics.

Another area where we remain unsure about future impacts is in studies of marine heatwaves in coastal areas. To get an insight into these coastal changes, CLEX researchers used a combination of four global satellite Sea Surface Temperature (SST) products. This range of products provided the best estimates of marine heatwave characteristics and long‐term changes of coastal marine heatwaves during the past 25 years. They found that hotspots were concentrated along the Mediterranean Sea, Japan Sea, south‐eastern Australia and the north‐eastern coast of the United States. They also found the frequency of marine heatwave events and their duration increased by 1–2 events per decade and 5–20 days per decade. Most of the marine heatwave hotspots identified were associated with strong upward trends in frequency and occurrence. The main driver of long‐term marine heatwave increases was long‐term changes in SSTs which, in the context of climate change, have been steadily increasing. In some regions like the south‐eastern Pacific coast, long‐term changes in marine heatwaves were driven by the local variability of the climate system.

While scientific understanding of oceanic events has continued to improve, it is also important for the public to understand and value our oceans, as building ocean literacy in communities can encourage responsible public behaviour towards the ocean and ocean resources. As part of the Future Seas project, Amelie Meyer co-authored a paper that summarized our knowledge and perspectives on ocean literacy from a range of disciplines, including marine biology, socio-ecology, philosophy, technology, psychology, oceanography and human health. The paper looked at the potential for positive change for a sustainable future based on the knowledge that already exists. A product of this paper was an Ocean Literacy Toolkit, which is a practical resource for enhancing ocean connections across many audiences and formats worldwide.

Following the idea of communicating our research, Denisse Fierro Arcos recently presented How a marine biologist uses statistics in her work in Spanish at the online conference Women in Data Science (WiDs) Ecuador.

But when it comes to career milestones receiving your PhD is perhaps one of the most important. It gives us great pleasure to acknowledge two recent PhD completions in ocean climate variability and/or extremes – those of Jiale Lou and Saurabh Rathore. We also wish to acknowledge two PhD submissions over the past few months – those of Abhishek Savita and Emilio Echevarria.

Finally, we welcome Kai Yang who will be starting his climate science journey as a PhD at the University of Tasmania, focusing on Are declines in coastal biodiversity driven by trends in frontal activity?  with supervisors Andy Fischer (UTAS), Amelie Meyer (UTAS) and Guy Williams (UTAS).