A mean heat | How the climate is driving marine heatwaves

In collaboration with the Deep South Challenge, we bring you this online seminar with Erik Behrens (NIWA), Tony Craig (Terra Moana, Sustainable Seas Challenge) and João De Souza (Moana Project).

Anyone who's been in the water this summer will have felt that things are heating up. Swimmers are talking about how the ocean is uncommonly warm and fishers are catching sub-tropical species further south than ever before. We're on the tail-end of a marine heatwave, and new research tells us these are going to get longer and stronger.

Marine heatwaves are already becoming a common experience for New Zealanders. In newly released research, scientists say that by 2100, the 40-odd marine heatwave days we currently see in a normal year will increase to between 80 days (low emissions, best-case scenario) and 170 days (high emissions, worst-case scenario) by the end of the century. For some regions, such as the southern tip of the South Island, there is a high chance that marine heatwaves start to last more than a year.  

The research also explores the intensity of future marine heatwaves, or just how warm they will be. For coastal waters, average marine heatwave intensities will increase by 20% (best case) to 100% (double, worst case) by the end of the century. For the North Island, this means an average marine heatwave could be between 0.5°C to 2°C more intense than they are today.

Research leader Erik Behrens (NIWA) says that the chance of marine heatwaves becoming a permanent fixture is worrying.

“Marine heatwaves kill off corals, disturb ecosystems, and can also pose a problem for fishing and aquaculture, as well as contributing to land heatwaves and climate extremes across the country.”

In this seminar, Erik Behrens will take you through his research into Marine heatwaves and the link with climate extremes and the project's latest journal article, alongside insights on what this might mean for our fisheries and marine ecosystems from Tony Craig, (Terra Moana and Co-Leader of our Upholding the value of pāua quota project), and João De Souza (Moana Project). 

This seminar is part of Deep South's Constant Change seminar series. A recording of this seminar will be available on Deep South's YouTube channel in the days following this seminar. 

About the presenters

Erik Behrens is an ocean modeller with expertise in developing high resolution nested earth system models. As part of the Deep South Challenge he developed a nested model for the New Zealand Exclusive Economic Zone (NZEEZ) to improve the representation of the oceanic circulation around NZ and, therefore, climate projections.

Tony Craig is Co-Leader of the Upholding the value of pāua quota project, which is investigating risks to rural pāua fishery infrastructure from climate related sea-level rise and storms. He is a partner at Terra Moana and has a depth of experience in fisheries and marine management.

João De Souza is MetOcean Solution’s Moana Project Director & Science Lead. João has an interdisciplinary background in ocean processes and data assimilative hydrodynamic simulations. Recently he has been developing marine forecast tools.

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