Record ocean heatwaves fuel storms, disrupt ecosystems, and cost billions

The world’s oceans saw a dramatic rise in marine heatwaves over the past two years, leading to deadly storms, mass coral bleaching, and disruptions to marine life and fisheries, a new study finds.

Sophie Kevany reports for The Guardian.


In short:

  • Marine heatwave days in 2023-24 were 3.5 times higher than in any previous recorded year, with nearly 10% of the ocean reaching record-high temperatures.
  • Warmer waters intensified storms, causing deadly floods and billions in damage, while also increasing whale and dolphin strandings as animals followed shifting prey.
  • Coral reefs and marine species suffered widespread harm, with some mitigation efforts — such as relocating coral — showing promise but lacking adequate resources.

Key quote:

“The more regularly our marine ecosystems are being hit by marine heatwaves, the harder it is for them to recover from each event.”

— Kathryn Smith, UK’s Marine Biological Association and lead author of the study

Why this matters:

Warmer oceans are reshaping the planet in ways that extend far beyond the coastline. As ocean temperatures climb, storms grow more intense, rainfall patterns shift, and vital marine ecosystems struggle to adapt. The consequences are felt worldwide, from flooded neighborhoods to disrupted food supplies. Coastal communities, particularly those reliant on fishing and tourism, face economic uncertainty as the ocean they depend on becomes increasingly volatile. Scientists warn that these trends will only accelerate without significant reductions in greenhouse gas emissions.

Related EHN coverage: Surprise! Unexpected ocean heat waves are becoming the norm

A field of green wheat stalks under a gray sky

British farmers saw ‘disappointing’ harvest and lower crop yields after hottest summer on record

Agriculture and Horticulture Development Board warned that the quality of the crops harvested has also been impacted.

A car's fuel gauge showing empty

How Trump is unintentionally helping the world’s climate

While the president remains a climate-change denier, the war with Iran has triggered an unforeseen benefit in the fight against global warming.
Whole barrel of oil and crude oil spilled from barrel on 100 dollar bills
Credit: Igorkol/BigStock Photo ID: 230323372

Fossil-fuel firms in line for billions in benefits after answering Trump’s donation call

Senators’ report says taxpayers face higher bills after "bargain" between president and major polluters.

A man with a hard hat and neon vest on, posing in front of an oil refinery

Germany to abandon fossil fuels by 2045. How does the rest of Europe compare?

Germany has become the third country in Europe to unveil a national roadmap away from fossil fuels. But experts say targets still 'fall short'.
Two energy workers on a roof shaking hands with solar panels in the background

Trump cut their climate jobs. This secretive network found them new ones

Climate Reserve has been quietly building a lifeline for America's lost climate workforce, one job at a time.
Illustrative example of AI cube as data transport and an also an intrusive entity being "plunked down" on a circuit board representative of a cityscape

AI’s meet-cute with climate denial

Just in time for Climate Week NYC, President Trump calls concerns over global warming and artificial intelligence a “hoax.”
A night time view of the Brooklyn Bridge with the city in the background

Newsom counters Trump's stance on climate issues while in New York

California Governor Gavin Newsom met with world and business leaders to advance climate action and clean energy in New York.

From our Newsroom
Multiple Houston-area oil and gas facilities that have violated pollution laws are seeking permit renewals

Multiple Houston-area oil and gas facilities that have violated pollution laws are seeking permit renewals

One facility has emitted cancer-causing chemicals into waterways at levels up to 520% higher than legal limits.

Regulators are underestimating health impacts from air pollution: Study

Regulators are underestimating health impacts from air pollution: Study

"The reality is, we are not exposed to one chemical at a time.”

Pennsylvania governor Josh Shapiro speaks with the state flag and American flag behind him.

Two years into his term, has Gov. Shapiro kept his promises to regulate Pennsylvania’s fracking industry?

A new report assesses the administration’s progress and makes new recommendations

silhouette of people holding hands by a lake at sunset

An open letter from EPA staff to the American public

“We cannot stand by and allow this to happen. We need to hold this administration accountable.”

wildfire retardants being sprayed by plane

New evidence links heavy metal pollution with wildfire retardants

“The chemical black box” that blankets wildfire-impacted areas is increasingly under scrutiny.

Stay informed: sign up for The Daily Climate newsletter
Top news on climate impacts, solutions, politics, drivers. Delivered to your inbox week days.