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Lookup NU author(s): Professor Pip MooreORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2024 The Authors. Marine heatwaves (MHWs), prolonged periods of unusually high ocean temperatures, significantly impact global ecosystems. However, there is ongoing debate regarding the definition of these extreme events, which is crucial for effective research and communication among marine scientists, decision-makers, and the broader public. Fundamental to all MHW analyses is a clearly defined background oceanic climate – i.e., a temperature ‘baseline’ against which the MHW is defined. While a single approach to implementing a baseline may not be suitable for all MHW research applications, the choice of a baseline for analysing MHWs must be intentional as it affects research outcomes. This perspective examines baseline choices and discusses their implications for marine organism and ecosystem risks, and their relevance in communicating MHW characteristics and metrics to stakeholders, policymakers, and the public. In particular we analyse five different baseline approaches for computing MHW statistics, assess their technical differences, and discuss their ecological implications. Different baselines suggest widely different trends in MHW characteristics in a warming world. This would, for example, imply differences in future risk, reflective of marine organisms with different adaptive potential, thereby affecting recommendations for management strategies. We also examine the consequences of different baseline choices on ease of implementation and communication with wider audiences. Our analyses highlight the need to clearly specify a chosen baseline in MHW studies, and to be mindful of its implications for MHW statistics, practical considerations, and interpretations concerning the adaptive capacities of marine organisms, ecosystems and human systems. The challenges and implications of different MHW baselines highlighted here have similar relevance in research and communication for other branches of climate extremes.
Author(s): Smith KE, Sen Gupta A, Amaya D, Benthuysen JA, Burrows MT, Capotondi A, Filbee-Dexter K, Frolicher TL, Hobday AJ, Holbrook NJ, Malan N, Moore PJ, Oliver ECJ, Richaud B, Salcedo-Castro J, Smale DA, Thomsen M, Wernberg T
Publication type: Article
Publication status: Published
Journal: Progress in Oceanography
Year: 2025
Volume: 231
Print publication date: 01/02/2025
Online publication date: 06/12/2024
Acceptance date: 04/12/2024
Date deposited: 07/01/2025
ISSN (print): 0079-6611
ISSN (electronic): 1873-4472
Publisher: Elsevier Ltd
URL: https://doi.org/10.1016/j.pocean.2024.103404
DOI: 10.1016/j.pocean.2024.103404
Data Access Statement: Data will be made available on request.
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