In a groundbreaking study led by Dr. Tommy Ryan-Keogh, principal researcher at the Council for Scientific and Industrial Research( CSIR), scientists have revealed an alarming decline in ocean productivity, a key process that sustains marine ecosystems and supports global food security.
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Declining ocean productivity and implications for the cold chain and food security By Eamonn Ryan, from a CSIR webcast
In a groundbreaking study led by Dr. Tommy Ryan-Keogh, principal researcher at the Council for Scientific and Industrial Research( CSIR), scientists have revealed an alarming decline in ocean productivity, a key process that sustains marine ecosystems and supports global food security.
The implications of this study extend far beyond theoretical climate projections.
This study, which critically evaluates the accuracy of existing climate models, has profound implications for global fisheries, coastal economies and the intricate cold chain systems that transport seafood across the globe.
The study, published in Nature ' s Communications Earth & Environment, highlights that ocean primary production has declined by an estimated 7-10 % over the past two decades, a trend largely driven by the rise in ocean temperatures. Phytoplankton, the primary producers of oxygen and food for marine life, have been under pressure from environmental changes, threatening marine biodiversity and food chains. Yet, perhaps more concerning, is that climate models currently used to project the future of ocean productivity have been significantly underestimating the scale of this decline.
THE LIMITATIONS OF CURRENT CLIMATE MODELS
One of the central findings of the study is the failure of climate models to accurately project the future of ocean productivity. Dr Ryan-Keogh and his team analysed satellite data spanning 26 years( 1998-2023) and discovered that while some models predicted an increase in ocean productivity, others projected no change or even a slight decline. When these diverse projections were averaged together, they suggested little to no change, an outcome that masked the true extent of the problem.
Ocean primary production is a critical process in the global carbon cycle. Phytoplankton photosynthesise, absorbing large amounts of carbon dioxide( CO 2
) from the atmosphere. When they die and sink to the ocean floor, they can trap carbon for hundreds to thousands of years, helping regulate the planet’ s climate. However, if ocean productivity continues to decline, this mechanism will weaken, leading to higher
CO 2 concentrations in the atmosphere and exacerbating climate change.
The models that are supposed to forecast these changes often provide conflicting results, creating a challenge for policymakers. Some climate models suggest that future ocean productivity will increase, while others predict a decline, making it difficult for decision-makers to determine the most likely outcomes and plan accordingly. This uncertainty is particularly worrying because ocean productivity is closely tied to marine biodiversity, and disruptions in this balance can have widespread consequences for food security.
A NEW APPROACH TO MODELING OCEAN PRODUCTIVITY
To address these discrepancies, the team developed an innovative‘ model ranking system’ to assess the accuracy of different climate models. By comparing their predictions with satellite data, the team was able to determine which models more accurately represented the observed decline in ocean productivity. The results were striking. While five out of six satellite algorithms agreed on the existence of a productivity decline, the climate models still underestimated the scale of this decline, projecting only minor changes.
This new ranking system allowed the team to pinpoint which models were most reliable in predicting the impact of environmental drivers like sea surface temperature and nutrient availability on ocean productivity. The study found that the best-performing models were the ones that predicted a decline in ocean productivity, but they still failed to fully capture the magnitude of the problem. This reinforces the need for climate models to better reflect the complex relationships driving ocean productivity and climate change.
IMPACT ON GLOBAL FISHERIES AND FOOD SECURITY
The implications of this study extend far beyond theoretical climate projections. The decline in ocean productivity is expected to have devastating effects on global fisheries, which provide food for billions of people worldwide. Dr Ryan-Keogh explains that more than three billion people rely on seafood as their primary source of protein, with some countries depending on fish for up to half of their protein intake. Any disruption to marine food chains can have dire consequences for food security, particularly in developing nations where seafood is a staple.
As ocean productivity declines, the availability of seafood is expected to diminish, leading to potential shortages. This puts pressure on the global food supply chain and highlights the need for better cold chain infrastructure. The cold chain will face significant challenges as the supply of fish becomes more volatile and the sourcing of seafood shifts to regions further afield.
Increased transportation times, higher refrigeration costs, and greater logistical complexity will put further strain on cold chain systems. Seafood will need to be shipped longer distances, and the infrastructure required to keep it fresh will need to be upgraded to meet these new demands. This increase in transportation costs and potential food waste will ultimately contribute to higher prices, exacerbating food insecurity for those who are already vulnerable.
A CRITICAL NEED FOR MITIGATION
The findings of this study underscore the urgent need for immediate climate action to mitigate the impacts of rising CO 2 emissions. Dr. Ryan-Keogh emphasised that reducing global CO 2 emissions is the most effective way to protect marine ecosystems and, by extension, food security. The study presents two scenarios: one in which emissions remain high, leading to a temperature rise of 3.6 ° C to 4.4 ° C by the end of the century, and another where emissions are reduced, leading to less severe temperature increases and smaller declines in ocean productivity.
The potential benefits of reducing emissions are clear. By mitigating climate change, we can help preserve ocean ecosystems, sustain fisheries, and ensure
that future generations will have access to the seafood they need for nutrition. However, if emissions continue unchecked, the decline in ocean productivity will likely accelerate, causing widespread disruptions to food systems, especially in regions that rely heavily on seafood.
As the study highlights, the global cold chain is intimately tied to the health of marine ecosystems. Seafood, being highly perishable, depends on refrigeration to maintain its freshness during transportation. With ocean productivity on the decline, seafood supply chains may be forced to adapt to longer shipping routes, higher storage requirements and increased energy consumption to maintain product quality.
These changes will place added strain on both the cold chain infrastructure and the consumers who rely on affordable, fresh seafood. Without immediate action to curb climate change and preserve ocean ecosystems, the disruptions to the cold chain and global food security will only worsen.
A CALL TO ACTION FOR POLICYMAKERS AND THE PUBLIC
The CSIR study is a stark reminder of the interconnectedness between ocean health, climate change, and global food security. Policymakers must take urgent action to mitigate emissions and protect marine ecosystems from further degradation. Similarly, scientists must continue to refine climate models to ensure they provide accurate projections of future changes in ocean productivity.
The study’ s findings also point to a need for greater awareness of the importance of the global cold chain. As seafood production becomes increasingly threatened, the logistics and infrastructure supporting its transportation must be prioritised and strengthened. The challenges posed by declining ocean productivity are global in nature and require a collaborative, multisectoral response to ensure that food security is not compromised. CLA
As the study suggests, the global cold chain is intimately tied to the health of marine ecosystems.
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