By Eamonn Ryan, from the webcast
The CSIR study, led by Dr Tommy Ryan-Keogh, reveals that climate models have underestimated the decline, threatening global ecosystems and food security. This is Part 4 of a five-part series on the urgent need for better climate models to secure global ecosystems and food security.
Dr Ryan-Keogh’s study, spanning 26 years of satellite data (1998-2023), shows a global decrease in ocean primary production by 7-10%. This decline, primarily due to rising ocean temperatures, disrupts marine ecosystems and food webs, with ramifications for the global food supply, especially for countries dependent on fishing. The study calls for more accurate models that better reflect the complex relationships between ocean productivity and environmental factors such as sea surface temperature.
The need for immediate action
The study presented by Dr Ryan-Keogh and his team serves as a stark reminder of the urgent need for comprehensive climate action. As ocean productivity continues to decline due to rising sea temperatures, the consequences for global ecosystems, food security, and economies dependent on fishing are becoming increasingly apparent.
The models currently used to predict future ocean productivity are still far from accurate, and this uncertainty complicates efforts to plan for future challenges. With global CO2 emissions continuing to rise, the potential for irreversible damage to marine ecosystems becomes ever more likely. However, as Dr Ryan-Keogh concluded, there is still hope: by drastically reducing our CO2 emissions, we can limit the damage and preserve ocean ecosystems and the services they provide.
The message is clear – time is running out, and the sooner we take action, the better the chance we have of safeguarding our oceans, our fisheries, and ultimately our planet.
A new model ranking system for climate predictions
To assess the reliability of current climate models, Dr Ryan-Keogh’s team developed a new ranking system that evaluates how well these models replicate observed changes in ocean primary production. The ranking system found that even the best-performing models predicted only a small decline of around 1% in ocean productivity, which was much less than the actual observed decline. This discrepancy highlights the need for more accurate models that can capture the real impacts of climate change on ocean ecosystems.
The urgency of climate mitigation and adaptation
The study emphasizes the importance of reducing global CO2 emissions to prevent severe consequences for ocean productivity. Dr Ryan-Keogh outlined two potential climate scenarios: one where CO2 emissions remain high, causing global temperatures to rise by 3.6 to 4.4°C, and another where emissions are reduced, limiting temperature increases to 1.4 to 2.7°C. The study’s findings underscore that mitigating emissions now can minimise the negative impacts on ocean ecosystems, helping to preserve critical services provided by the oceans.
Implications for global food security and fishing economies
Dr Ryan-Keogh stressed the interconnectedness of ocean productivity and global food security. The decline in ocean primary production will directly impact the availability of seafood, a critical food source for billions of people worldwide. However, the effects will not be uniform. Some regions may see an increase in productivity, while others may experience significant declines. The study underscores the need for strategies to protect marine ecosystems and ensure the sustainability of fisheries, especially in regions that rely heavily on seafood.