How Marine Heatwaves Are Spreading Across the Globe

                        Marine Heatwaves
Periods of abnormally high sea surface temperatures are becoming more frequent and intense due to climate change.
These events can have devastating effects on marine ecosystems, leading to coral bleaching, shifts in species distributions, and disruptions to fisheries.

What Are Marine Heatwaves?

A marine heatwave is defined as a period during which water temperatures are abnormally warm for the time of year, persisting for days to months.

These events can span thousands of kilometres and affect various depths in the ocean. 

They are driven by factors such as ocean currents, atmospheric conditions, and human-induced climate change.

Global Impact

Recent studies have shown that marine heatwaves are occurring more frequently across the globe.

Notable events include:

• The 2011 marine heatwave off Western Australia, which led to a rapid dieback of kelp forests.
• The 2015–2016 "Blob" in the Northeast Pacific, a prolonged warm water event that disrupted marine life.
• The 2016 heatwave in the Great Barrier Reef, resulting in widespread coral bleaching.

Consequences for Marine Life

Marine heatwaves can lead to:

• Coral bleaching and reef degradation.
• Shifts in species distributions, affecting biodiversity.
• Disruptions to fisheries and local economies dependent on marine resources.

What Can Be Done?

Mitigating the effects of marine heatwaves involves:

• Reducing greenhouse gas emissions to combat climate change.
• Implementing marine protected areas to enhance ecosystem resilience.
• Monitoring ocean temperatures to provide early warnings for marine heatwave events.

Links

• The New York Times – See How Marine Heat Waves Are Spreading Across the Globe (2025)
• NOAA – Ocean Heatwaves
• Nature Climate Change – Increasing marine heatwaves under global warming
• Nature Climate Change – Western Australia’s 2011 Marine Heatwave
• Nature Climate Change – The ‘Blob’ in the Northeast Pacific
• Nature – Global warming and recurrent mass bleaching of corals
• IPCC Special Report on the Ocean and Cryosphere in a Changing Climate
• Scientific American – Marine Heat Waves Are Deadly and Getting Worse