NEWSTALK BREAKFAST
with Anton Savage
Rowan Byrne on rising ocean temperatures
Marine biologist Rowan Byrne joined Anton Savage on Newstalk Breakfast on 25 August 2026 to discuss the continuing rise in ocean temperatures and what this means for marine life, fisheries and the wider ocean ecosystem.
The discussion followed reports that the world's oceans had reached their highest recorded average surface temperature, with a reported average of approximately 21.1°C.
Rowan explained why ocean temperature matters so much to marine ecosystems. Changes in temperature can influence where fish and other marine species live, how they migrate and behave, and the relationships between species throughout the marine food web.
The conversation also explored the additional pressures already facing the ocean, including overfishing, plastic pollution and other forms of pollution, and how climate-driven changes can add another layer of stress to ecosystems already under pressure.
Rowan Byrne's central message
"The ocean is our provider. It maintains our weather, our food sources and does many things for us."— Rowan Byrne, Newstalk Breakfast, 25 August 2026
Paraphrase based on interview content. Exact wording may differ from broadcast.
Why rising ocean temperatures matter
Temperature is one of the fundamental factors controlling marine ecosystems. The ocean absorbs the majority of excess heat generated by human-caused climate change, and even small changes in average sea surface temperature can have significant consequences for marine life.
When water temperatures change, species may respond in a range of ways. Fish and other marine animals may move into different areas as their preferred temperature range shifts. Migration routes can change. Feeding patterns, reproductive behaviour and interactions with other species can all be affected. These changes do not happen in isolation — marine ecosystems are deeply interconnected, and a shift in one part of the food web can have consequences throughout.
Species responses to changing ocean temperatures:
- Moving into different areas as preferred temperature ranges shift
- Changing migration routes
- Altering feeding patterns
- Changing where and when they reproduce
- Interacting differently with other species
- Responding to changes in prey availability
Because marine ecosystems are interconnected, changes in one species or habitat can have consequences throughout the food web — from plankton to apex predators.
Why plankton matters
During the interview, Rowan highlighted the importance of plankton not only as the foundation of marine food webs but also as major participants in the global carbon cycle.
Plankton — microscopic organisms that drift through the ocean — form the base of most marine food chains. Almost everything in the ocean depends on them directly or indirectly. They are also responsible for producing a significant proportion of the oxygen in Earth's atmosphere and play a critical role in absorbing carbon dioxide from the atmosphere.
Attribution note
Rowan mentioned during the interview a figure of approximately 50 billion metric tonnes of carbon annually in the context of the ocean's role in the carbon cycle. This figure is attributed to the interview and has not been independently verified for this article. Changes in ocean temperature can affect plankton populations, with potential consequences for the entire marine food web and for the ocean's capacity to absorb carbon.
The changing waters around Ireland
Rowan used the waters around Ireland as a real-world example of how warming seas are already changing the species found in European waters. Warming ocean temperatures can alter which species are present in Irish and surrounding waters, where they are found, and in what numbers.
During the interview, Rowan discussed the example of tuna appearing increasingly in Irish and surrounding waters — a species not historically associated with Irish fisheries. The arrival or movement of species like this can create challenges for fisheries management, because existing management systems and catch limits may not always be designed around rapidly changing species distributions.
The important issue, as Rowan explained, is that the marine ecosystem is changing, and the consequences are still being understood. Not every change is necessarily negative, but the pace and scale of change presents real challenges for conservation, fisheries management and marine science.
A changing ocean under multiple pressures
Climate change is not acting in isolation. The ocean is simultaneously affected by a range of human-caused pressures, and these can interact in ways that make ecosystem responses harder to predict.
Ocean warming
Rising sea surface and deep-water temperatures affecting species distributions and behaviour
Overfishing
Removal of key species disrupting food web balance and ecosystem resilience
Plastic pollution
Microplastics and larger debris affecting marine life at every level of the food chain
Other pollution
Chemical runoff, nutrient pollution and other contaminants stressing marine habitats
Habitat degradation
Loss of coral reefs, seagrass meadows and other critical marine habitats
Ecosystem change
Cascading effects as multiple pressures interact across interconnected marine systems
Climate change adds another pressure to marine ecosystems that are already dealing with fishing pressure, pollution and habitat change. Multiple pressures can interact, making ecosystem responses harder to predict and management more complex.
El Niño — a simple explanation
El Niño is a natural climate phenomenon involving changes in the movement of warm and cold water across the tropical Pacific Ocean. Normally, trade winds help push warm surface water westwards, while colder, nutrient-rich water rises towards the eastern Pacific. During El Niño, changes in those winds and ocean circulation alter that pattern.
Analogy
"Think of the Pacific like a giant bathtub. El Niño is a natural change in the way the water sloshes around the bath. Climate change is different: it is like gradually turning up the temperature of the water itself."
El Niño is a natural phenomenon. Human-caused climate change is increasing the amount of heat being retained in the climate system and absorbed by the ocean. These processes should not be confused, although they can interact — a warming baseline can influence the intensity and effects of El Niño events.
El Niño explanation based on Rowan Byrne's interview on Newstalk Breakfast, 25 August 2026.
Listen to the interview
Rowan Byrne on Newstalk Breakfast with Anton Savage
Rowan discusses record ocean temperatures, marine ecosystems, fisheries, plankton, climate change, pollution, overfishing and El Niño.
Listen on Newstalk / GoLoud →Source: Newstalk / GoLoud. Audio hosted by Newstalk. MarineCreatures.com does not own or host this recording.
Rowan Byrne — Marine Biologist & Marine Ecologist
Rowan Byrne BSc (Hons), MSc, FRSB, CSci
Rowan Byrne has more than 30 years of experience in marine biology, marine ecology, conservation, research, environmental consultancy, marine plastics, fieldwork, marine wildlife, underwater environments and public engagement with science.
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