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