Scientists warn that the ocean is running out of oxygen at an unprecedented rate as a result of the climate emergency.

Multiple ecosystems are in danger of collapse with sharks, tuna, marlin and other large fish species at particular risk.

The last 50 years have seen a qraduple increase in the presence of dead zones – where oxygen is effectively absent – and there are at least 700 areas where oxygen is at dangerously low levels, up from 45 initially recorded in the 1960s.


The International Union for the Conservation of Nature (IUCN) presented the findings on Saturday, December 7, at the UN Climate Conference in Madrid, where officials are negotiating methods of tackling this crisis.

Grethel Aguilar, the acting director general of the IUCN, said ocean health needs to be a key consideration in the talks. ‘As the warming ocean loses oxygen, the delicate balance of marine life is thrown into disarray,’ she said, as per The Guardian.

The director general continued:

The potentially dire effects on fisheries and vulnerable coastal communities mean that the decisions made at the conference are even more crucial.

Some parts of the ocean are naturally lower in oxygen than others, and therefore are even more susceptible to damage when their oxygen levels are further depleted, the report’s authors said.


More adaptable species such as jellyfish can flourish at the expense of other fish as they can handle low oxygen environments, upsetting the balance of ecosystems even further.

While all fish need dissolved oxygen, the larger species are particularly vulnerable to depleted oxygen levels because they need much more of it to survive. Evidence shows these depleted levels are forcing them to move towards the surface and to shallow areas of the sea, where they are more susceptible to fishing.

In recent years, the threat to the oceans has become far more severe due to climate change and global warming. In fact, oceans are expected to lose around 3-4% of their oxygen by the end of this century.

Changing the outcome of what will happen to the oceans is the responsibility of the world’s political leaders, which is why the report has been launched at the UN Climate Conference.