By Robin McKie
Published: Nov. 23, 2024
Britain is bracing for a future of devastating marine heatwaves, which are increasingly threatening the nation’s coastal ecosystems, fisheries, and marine biodiversity. A new report from the National Oceanography Centre (NOC) warns that urgent research is needed to address the growing impact of these sudden temperature spikes on sea creatures, plant life, and coastal communities.
Marine Heatwaves on the Rise
Marine heatwaves, characterized by abnormally high sea temperatures, are becoming more frequent and intense due to global warming fueled by rising fossil fuel emissions. These heatwaves not only disrupt ecosystems but also lead to severe consequences, including:
- Mass mortality of marine species such as shellfish, fish, seabirds, and marine mammals.
- Bleaching of coral reefs and destruction of seagrass meadows.
- Spread of harmful algal blooms that further destabilize marine environments.
“Marine heatwaves have catastrophic impacts, and we need to be prepared for them,” said Dr. Zoe Jacobs, lead author of the NOC report, Marine Heatwaves and Cold Spells in the Northeast Atlantic. “At present, we are not, and that position needs to be rectified as a matter of urgency.”
Impact on UK Waters
In the summer of 2023, a marine heatwave engulfed British waters, with sea temperatures off the north-east coast of England and west of Ireland rising by up to 5°C above normal. This shattered records dating back to 1850. The Met Office confirmed that the North Sea and North Atlantic experienced unprecedented temperature highs during this period.
The report identifies three key regions around the UK at high risk of marine heatwave impacts:
- The Irish Sea between England and Ireland.
- The North Sea off northern England and Scotland.
- The south-east coast of England.
“These areas are particularly vulnerable because marine heatwaves in these regions often coincide with extremely low oxygen levels in the water,” Jacobs explained. “This double whammy causes significant stress to marine life, threatening their survival.”
Fisheries and Marine Ecosystems at Risk
Last year’s heatwave led to anecdotal reports of widespread shellfish die-offs and disruptions to fisheries, particularly whelk populations. However, without targeted research, the full extent of the damage remains unknown.
The report warns that if marine heatwaves continue unabated, the UK’s fisheries may face closures, while critical restoration efforts—such as those targeting seagrass meadows—could be jeopardized. Seagrass, which absorbs high levels of carbon and provides habitats for diverse marine species, is especially at risk.
“Global temperatures are rising, and marine heatwaves are already having catastrophic impacts in other parts of the world,” said Jacobs. “We need to identify our most vulnerable regions and develop strategies to protect them.”
A Call for Action
The NOC is urging the government and research institutions to:
- Launch targeted research programs to study the long-term effects of marine heatwaves on UK marine ecosystems.
- Identify resilient species of plants like seagrass that can withstand higher temperatures.
- Monitor vulnerable regions closely to anticipate and mitigate the impacts of marine heatwaves.
- Implement adaptive management strategies such as fisheries closures or quotas during extreme events.
Lessons from Global Examples
Around the world, marine heatwaves have already forced drastic measures. In Australia, entire fisheries have been closed, and vast areas of seagrass have been wiped out. Similar approaches may be required in the UK to mitigate future impacts.
“Proactive measures are essential to ensure the survival of marine life and the sustainability of coastal communities,” Jacobs concluded.
Key Takeaways
- Marine heatwaves are becoming more frequent and severe, driven by global climate change.
- These events threaten UK fisheries, marine biodiversity, and coastal ecosystems.
- Targeted research and urgent action are needed to protect vulnerable regions and species.
- Adaptive measures such as fisheries closures may become necessary as heatwaves intensify.
