What record-high ocean temperatures could mean for marine life and people

August marked the highest ocean surface temperatures ever recorded and the impacts are vast

Olive ridley turtle (Lepidochelys olivacea) hatchlings walking towards sea at sunrise.

Our oceans are hotter than ever—literally. August yielded the highest surface temperatures ever recorded, which is alarming for many reasons, though perhaps not surprising considering the ocean absorbs 90% of the planet's excess heat and is already the world's largest carbon store. Warmer air will inevitably lead to warmer oceans.

The ocean is a life-support system for the planet; from generating the oxygen in the air we breathe to providing us with trillions of dollars' worth of food. In fact, 3 billion people depend on seafood for their nutrition and over 600 million people depend on the fishing industry for their livelihoods. To further complicate the issue, as the impacts of the climate crisis grow, the pressure on the ocean will only increase. So how are record-warm oceans affecting wildlife and the people who depend on them?

Some fish, like herring and whiting, are moving toward the polar regions in search of cooler water. Sudden warming can decimate these fisheries. They need stable water temperatures within specific ranges to spawn and maintain healthy populations.

Other fish, like black seabream, are moving away from coastal areas into deeper water, which can further environmental injustices. This can have a profound effect on small-scale, artisanal fishers, who don't have vessels equipped for longer distance, deepwater fishing—deepening inequities between under-resourced coastal communities and large-scale industry.

Species that live or spawn in coastal habitats, like mangrove forests and coral reefs, can die off. For example, coral bleaching events from warm, acidified water have been found to affect the behavior and nutrition of reef fish like butterflyfish, which in turn impact the surrounding wildlife and the dynamics of the whole ecosystem.

Species that already live in deep, cold waters are disappearing.
The Alaska snow crab fishery collapse earlier this year had complex causes, but NOAA confirms that factors related to "heatwave conditions," even as deep as the ocean floor in the Bering Sea, contributed to the die-off.

Marine mammals and seabirds are affected, too.
There are hundreds of thousands of other non-human species like whales and other marine mammals that feed on migrating fish and other prey species like krill that now have to travel much longer distances to find food, and are potentially experiencing challenges in birthing and rearing their offspring. Bird species that are consumed by subsistence-based communities, like auklets, can also experience mass die-offs as the location of their marine food sources move away from historical locations. And species that rely on sea ice for hunting food, like polar bears, are particularly vulnerable as seas warm.

What is WWF doing to help prevent and mitigate these effects?

WWF and our partners follow an integrated approach that focuses on priority geographies to support climate adaption strategies and increase resilience of key ecosystems and species. We're continuing to evolve our area-based conservation work in seascapes where food sourcing, community livelihoods, coastal development, and nature-based climate solutions converge.
This holistic approach involves scientific research to study rapidly changing ecosystems, collaborating with industry to develop climate-smart and sustainable fishing practices, and partnering with local people and Indigenous communities to design conservation strategies that center human wellbeing and sustainable livelihoods.

We're also looking beyond what's happening today (sadly, climate modeling forecasts that current trends will continue for many years) toward what could happen tomorrow through our new initiative, Oceans Futures. This program is designed to leverage emerging tech like predictive analytics and AI to better understand how, when, and where climate-driven fish stock migration will lead to further food insecurity. This work also includes collaboration with international agencies like the UN Office on Drugs and Crime to help prevent and mitigate potential conflicts between nations over the moving targets that fish represent in a warming world.