Earth’s climate is now more off-balance than ever before, with the past decade (2015-2025) confirmed as the hottest eleven-year period on record. The World Meteorological Organization’s (WMO) latest State of the Global Climate report reveals a disturbing trend: oceans are absorbing unprecedented levels of heat, exceeding all previous measurements.
Record Ocean Heat Content
In 2025, ocean heat content reached an all-time high, surpassing the previous record set in 2024 by a staggering 23 zettajoules (23,000,000,000,000,000,000,000 joules). This is a drastic increase, considering the 14-zettajoule jump between 2020 and 2021 was already considered alarming. The sheer scale of energy being absorbed is difficult to comprehend: the report equates it to detonating twelve Hiroshima-sized bombs in the ocean every second of the year.
Why this matters: Oceans absorb roughly 91% of excess heat from greenhouse gas emissions, preventing more immediate warming on land. However, this doesn’t mean the heat disappears; it accumulates, fueling extreme weather, marine heatwaves, and long-term climate destabilization.
Energy Imbalance and Long-Term Effects
The WMO report is the first to highlight Earth’s energy imbalance as a key indicator. In a stable climate, energy received from the sun would roughly equal energy radiated back into space. But with greenhouse gases trapping heat, that balance is destroyed.
- Only 1% of excess energy is stored in the atmosphere.
- 5% accumulates on land, contributing to heat islands.
- 3% warms ice, accelerating glacial melt.
- The remaining 91% goes into the oceans.
Even if greenhouse gas emissions were halted immediately, the Southern Ocean alone would continue to release stored heat for at least a century, perpetuating warming. This means past emissions have locked in future warming, regardless of immediate action.
Extreme Weather and Marine Life at Risk
The hotter oceans directly fuel more frequent and intense extreme weather events. The report cites several devastating storms in 2025, including Hurricane Melissa, Tropical Cyclones Senyar and Ditwah, and typhoons in Vietnam and the Philippines.
The crisis for marine life is equally dire. Rising ocean temperatures and increasing acidity (from absorbed carbon dioxide) threaten plankton – the foundation of marine food webs. More acidic waters dissolve the shells and skeletons of these organisms, leading to ecosystem collapse. Marine heatwaves also cause widespread die-offs, further releasing greenhouse gases as decaying organisms decompose.
The Connection to Global Security
UN Secretary-General António Guterres warns that climate stress is destabilizing global security, alongside ongoing conflicts. “Our addiction to fossil fuels is destabilizing both the climate and global security,” he stated. The report underscores that delay in addressing climate change is now “deadly.”
The WMO report draws on data from national meteorological services, UN partners, and dozens of experts, confirming the urgency of the situation.
The inescapable conclusion is that the climate crisis is accelerating, and immediate, drastic action is required to prevent catastrophic consequences.
