Be it a water molecule in the Humboldt Current, a rubber ducky that fell from a shipping vessel, or a school of tuna on a trans-oceanic migration, everything in the ocean is in constant motion; it is the most dynamic system on earth. Therefore, unlike on land — where environmental damage is often localized to a specific region or country — the many stresses on marine habitats are tightly interlinked and can have substantial global repercussions.
Last week, the Nereus Program released a report entitled, Predicting Future Oceans: Climate Change, Oceans & Fisheries. This document, which includes academic contributions from over 40 marine and fisheries scientists at six institutions, highlights seven key concerns with regard to current and future ocean health in the context of climate change:
- Due to CO2 emissions, changes in global ocean properties — particularly temperatures, acidity and oxygen levels — are occurring at a scale unprecedented in the last several thousands of years.
- Climate change is expected to affect the oceans’ biological productivity — from phytoplankton to top predators.
- Climate change has already been affecting global marine ecosystems and fisheries, with further impacts expected given current trends in CO2 emissions.
- Fishing exerts significant pressure on marine ecosystems globally — altering biodiversity and food web structures — and affects the ability of the international community to meet its sustainability goals.
- The impacts of climate change interact with the existing problems of overfishing and habitat destruction, driven largely by excess fishing fleets, coastal development and market expansion.
- Aquaculture is developing rapidly, with the potential to supersede marine capture fish supply. Yet, the full understanding of its impact, including its long-term ecological and social sustainability, is unclear.
- Sustainable fisheries in the future require the further development and strengthening of international fisheries law, as well as the overarching international framework for ocean governance.
Building on research into alterations in the ocean’s chemistry, the report discusses how fish, fisheries and aquaculture production will be affected by climate change in the future. Rising temperatures are already causing fish stocks to move gradually toward the poles (where water is cooler) and increases in carbon dioxide are reducing nutrient availability for creatures at the base of the food web. It’s estimated that three billion people depend on seafood for a part of their daily protein, and more than 10 per cent of the world’s population earns a living from fishing and aquaculture. These ecological responses will have important economic and food security implications for people around the world in the years to come. Co-director of the Nereus Program, Dr. Yoshitaka Ota, said he believes that the report “shows the hard truth of the current state of the world’s oceans.”
From overfishing to pollution and coastal development, the oceans are currently facing a variety of serious anthropogenic threats. This report connects these dots under the bigger umbrella of climate change and paints a picture that suggests we are not doing enough to mitigate our impacts. Dr. Ota hopes this work will start a meaningful conversation by providing policy makers and the public with something that gives them the courage to speak out about their concerns.