New scientific findings reveal that climate change is accelerating the expansion of oxygen-depleted zones—often called dead zones—in coastal seas around the world. These low-oxygen areas, which make it nearly impossible for marine life to survive, are spreading as ocean temperatures rise and human activity intensifies.

In regions like the Baltic Sea, the problem is becoming increasingly severe. Warmer waters are reducing the ocean’s ability to hold oxygen, while nutrient pollution from agriculture and wastewater fuels algal blooms. When these algae die and decompose, they consume even more oxygen, leaving behind suffocating conditions for fish, crustaceans, and other sea creatures.

Under normal circumstances, ocean mixing helps transport oxygen from surface waters to deeper layers. However, as global temperatures increase, this process weakens. Warmer surface water becomes lighter, preventing deeper water from receiving sufficient oxygen. The result is an expanding layer of hypoxic water that threatens entire marine ecosystems.

Scientists warn that these oxygen minimum zones (OMZs) are not limited to one region—they are growing across the globe. From the Baltic to the Gulf of Mexico and the Arabian Sea, these “dead zones” are encroaching into shallower waters, shrinking the habitable space for marine life and disrupting food webs.

The consequences extend beyond ecology. Coastal fisheries and aquaculture industries are already feeling the impact as fish populations decline and species migrate away from oxygen-depleted areas. The loss of biodiversity and collapse of marine productivity also pose long-term risks to food security and local economies.

Experts emphasize that the expansion of dead zones can still be slowed with decisive action. Reducing greenhouse gas emissions, limiting nutrient runoff from farms, and improving wastewater management are key steps. Strengthening coastal monitoring and restoration efforts can also help restore oxygen balance in affected regions.

As the oceans continue to warm, the message from scientists is clear: protecting oxygen levels in the sea is protecting the foundation of marine life itself. Without immediate intervention, these growing dead zones could redefine the future of the world’s coastlines.