The heat is on: what we know about why ocean temperatures keep smashing records
Retrieved on:
Wednesday, April 10, 2024
Ocean temperatures have been steadily rising due to human-caused global warming, which in turn means record hottest years have become increasingly common.
Key Points:
- Ocean temperatures have been steadily rising due to human-caused global warming, which in turn means record hottest years have become increasingly common.
- The last time ocean temperature records were broken was 2016 and before that it was 2015.
- The last year we experienced a record cold year was way back at the start of the 20th century.
- But what is remarkable about the past year is the huge ongoing spike in global ocean temperature which began in April last year.
How big is the jump in heat?
You can see the surge in heat very clearly in the near-global ocean surface temperature data.
The trend is clear to see. Earlier years (in blue) are typically cooler than later years (in red), reflecting the relentless march of global warming. But even with this trend, there are outliers. In 2023 and 2024, you can see a huge jump above previous years. These record temperatures have been widespread, with the oceans of the southern hemisphere, northern hemisphere and the tropics all reaching record temperatures.
What’s behind the surge?
- The extra heat pouring into the oceans results in a gradual rise in temperature, with the trend possibly accelerating.
- But this alone doesn’t explain why we have experienced such a big jump in the last year.
- Other natural heat-transferring oscillations, such as the Indian Ocean Dipole or the North Atlantic Oscillation, may play a role.
- Read more:
An 'extreme' heatwave has hit the seas around the UK and Ireland – here's what's going on
Why is this important?
- But the extra heat manifests underwater as an unprecedented series of major marine heatwaves.
- If the heat spikes too much and for too long, they have to move or die.
- Marine heatwaves can lead to mass death or mass migration for marine mammals, seabirds, fish and invertebrates.
- They can cause vital kelp forests and seagrass meadows to die, leaving the animals depending on them without shelter or food.
What’s going to happen next?
- In the next few months, forecasts suggest we have a fair chance of heading into another La Niña.
- If this eventuates, we might see slightly cooler temperatures than the new normal, but it’s still too early to know for sure.
- Read more:
Ocean heat is off the charts – here's what that means for humans and ecosystems around the world
- Alex Sen Gupta receives funding from receives funding from the Australian Research Council.
- Thomas Wernberg receives funding from The Australian Research Council, The Norwegian Research Council, The Schmidt Marine Technology Partners and Canopy Blue.