Marine Heatwave Days Triple as Ocean Sensors Close
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- Marine heatwave days in 2025 were more than triple the count recorded in the early 1990s, a signal that the ocean's role as a climate buffer is straining under accumulated heat
- The ocean has absorbed more than 90% of excess heat trapped by human activity, but that stored heat is now surfacing as coral bleaching, kelp forest loss, and ecosystem collapse
- Earth's energy imbalance — the gap between incoming solar energy and outgoing辐射 — has more than doubled since the late 20th century, driven by greenhouse gases and reinforcing feedbacks like ice-to-ocean albedo loss
- Human-induced warming has reached approximately 1.37C above pre-industrial levels, with sea-level rise more than doubling in recent decades to a new record of 23cm since 1901
- Four of five ocean monitoring sites across the Pacific and Atlantic are set to close, with equipment already being pulled from the water even as the next UN climate assessment is not due until 2028
- The IGCC report was compiled by more than 70 researchers from over 50 institutions as an annual climate health check to fill the gap between official UN assessments
Why it matters: Coastal communities that depend on the sea for food and livelihoods face immediate harm as marine heatwaves intensify, while the simultaneous closure of four of five Atlantic and Pacific monitoring sites means scientists are losing the sensor network needed to track the energy imbalance at the very moment it is accelerating fastest.
