Mass extinctions in oceans may be inevitable - Hawaii News Now - KGMB and KHNL

Scientists warn of mass extinctions in world's oceans

A changing climate is part of the problem causing environmental degradation in the world's oceans, a study suggested. (Source: NOAA) A changing climate is part of the problem causing environmental degradation in the world's oceans, a study suggested. (Source: NOAA)

(RNN) - A team of marine scientists issued a dire warning Oct. 3 on the state of the world's oceans. They say that mass extinctions may already be inevitable.

A report issued by the International Programme on the State of the Ocean and the International Union for Conservation of Nature states that the world's oceans are experiencing decreasing oxygen levels, warming and acidification as a result of several stressors, including climate change, pollution and overfishing.

"The health of the ocean is spiraling downwards far more rapidly than we had thought," said Alex Rogers, the scientific director of IPSO. "We are seeing greater change, happening faster, and the effects are more imminent than previously anticipated. The situation should be of the gravest concern to everyone since everyone will be affected by changes in the ability of the ocean to support life on Earth."

These factors have serious consequences for marine life, as temperature, chemistry, nutrient and oxygen supply all are necessary for the oceans to support an abundance of marine life.

If the amount of carbon dioxide absorption remains at its current level, by about 2030 or 2050, the carbon dioxide content in the oceans is expected to cause coral reefs to erode and lead to the extinction of some species.

Coral reefs provide shelter and protection for several species of fish, according to Texas A&M University, as well as helping to control the level of carbon dioxide in the oceans.

A United Nations climate change panel report released in late September noted that the ocean is absorbing much of the increasing heat from the changing climate. The International Programme on the State of the Ocean's report noted that the warming of the world's oceans will have negative effects, including further reducing oceanic oxygen levels.

Melting Arctic ice will also cause more methane to be released into the atmosphere, contributing to climate change. Seasonal ice zones will continue to shrink, with Arctic summer sea ice disappearing by about 2037.

"Potential knock-on effects of climate change in the ocean, such as methane release from melting permafrost, and coral dieback, mean the consequences for human and ocean life could be even worse than presently calculated," the report noted.

Marine life is also stressed by overfishing, with about 70 percent of the world's fish populations harvested in an unsustainable manner.

Suggestions put forward by the study include further reducing global carbon emissions below the current targets and better management of vulnerable marine ecosystems.

"What these latest reports make absolutely clear is that deferring action will increase costs in the future and lead to even greater, perhaps irreversible, losses," said IUCN's Dan Laffoley.

The findings were published in the peer-reviewed journal Marine Pollution Bulletin.

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