Global Oceans Suffer Most Devastating Heatwave in Nine Consecutive Years
A staggering 365 million Hiroshima-sized atomic bombs' worth of energy has been absorbed by the world's oceans, setting a record for the ninth year running. This alarming trend is attributed to rising greenhouse gas emissions, which scientists warn are exacerbating extreme weather events, sea-level rise, and destabilizing marine ecosystems.
The consequences are already being felt across communities worldwide, particularly through intensified storms and severe flooding. The most recent examples include the devastating monsoon rains that claimed over 1,300 lives in Southeast Asia in 2025, and flash floods in Central Texas that killed at least 138 people, including 27 young campers and counselors.
Researchers point to these catastrophic events as evidence of the catastrophic impact of marine warming. In fact, Earth's oceans are acting as its primary thermal energy sink, absorbing an alarming 90% of the excess heat trapped by greenhouse gases in the atmosphere. This is having a profound effect on global climate impacts, fueling storm intensification and contributing to increased atmospheric moisture and energy availability.
To calculate the magnitude of ocean heat absorption, scientists measured temperature fluctuations in the upper 6,500 feet of the global ocean, finding that it was about 23 zettajoules higher than it was at the end of 2024. This made 2025 the hottest year on record for Ocean Heat Content (OHC).
The alarming trend is not expected to abate anytime soon. In fact, researchers warn that unless net-zero carbon emissions are achieved, the global ocean heat content will continue to rise. The consequences are already being felt in extreme weather events and sea-level rise, with coral reefs also under severe threat.
With a staggering 84% of the world's coral reef area experiencing bleaching-level heat stress since January 2023, mass coral bleaching has been documented in at least 83 countries and territories. Unless rapid emissions reductions can be achieved, this trend is expected to continue, threatening not just coral reefs but entire ecosystems.
The importance of strengthening ocean monitoring and uncovering the mechanisms behind ocean heat redistribution cannot be overstated. By doing so, communities worldwide can begin to adapt to a new climate reality and build resilience in the face of an increasingly unpredictable future.
A staggering 365 million Hiroshima-sized atomic bombs' worth of energy has been absorbed by the world's oceans, setting a record for the ninth year running. This alarming trend is attributed to rising greenhouse gas emissions, which scientists warn are exacerbating extreme weather events, sea-level rise, and destabilizing marine ecosystems.
The consequences are already being felt across communities worldwide, particularly through intensified storms and severe flooding. The most recent examples include the devastating monsoon rains that claimed over 1,300 lives in Southeast Asia in 2025, and flash floods in Central Texas that killed at least 138 people, including 27 young campers and counselors.
Researchers point to these catastrophic events as evidence of the catastrophic impact of marine warming. In fact, Earth's oceans are acting as its primary thermal energy sink, absorbing an alarming 90% of the excess heat trapped by greenhouse gases in the atmosphere. This is having a profound effect on global climate impacts, fueling storm intensification and contributing to increased atmospheric moisture and energy availability.
To calculate the magnitude of ocean heat absorption, scientists measured temperature fluctuations in the upper 6,500 feet of the global ocean, finding that it was about 23 zettajoules higher than it was at the end of 2024. This made 2025 the hottest year on record for Ocean Heat Content (OHC).
The alarming trend is not expected to abate anytime soon. In fact, researchers warn that unless net-zero carbon emissions are achieved, the global ocean heat content will continue to rise. The consequences are already being felt in extreme weather events and sea-level rise, with coral reefs also under severe threat.
With a staggering 84% of the world's coral reef area experiencing bleaching-level heat stress since January 2023, mass coral bleaching has been documented in at least 83 countries and territories. Unless rapid emissions reductions can be achieved, this trend is expected to continue, threatening not just coral reefs but entire ecosystems.
The importance of strengthening ocean monitoring and uncovering the mechanisms behind ocean heat redistribution cannot be overstated. By doing so, communities worldwide can begin to adapt to a new climate reality and build resilience in the face of an increasingly unpredictable future.