Acidic oceans threatening life on Earth

The world's oceans are becoming too acidic to support life, the Potsdam Institute for Climate Impact Research has said.

The institute, which is known as the PIK, said in a study released this week that the acidity of the oceans is one of nine factors it believes are critical for the planet's ability to regulate life-sustaining natural systems.

It said safe levels have already been exceeded in six of the nine areas because of human activity, and the dangerously high levels of acidification in the planet's oceans could soon become the seventh.

"As CO2 emissions increase, more of it dissolves in seawater ... making the oceans more acidic," AFP quoted Boris Sakschewski, one of the report's lead authors, as saying. "Even with rapid emission cuts, some level of continued acidification may be unavoidable due to the CO2 already emitted and the time it takes for the ocean system to respond. Therefore, breaching the ocean acidification boundary appears inevitable within the coming years."

The acidification of the oceans is down to emissions of CO2 resulting from the burning of fossil fuels.

The PIK's report, titled Planetary Health Check, said the acidification of the oceans not only makes it harder for them to support life directly but also means they are less able to help stabilize the climate by continuing to absorb CO2 emissions.

People would be impacted because of the loss of marine food sources and the fact that more CO2 would end up in the atmosphere, adding to the problem of global warming.

The PIK said it developed its set of nine planetary danger levels to help make people aware of how close we have come to pushing some of the planet's natural systems beyond the point of no return.

"These tipping points ... if crossed, would lead to irreversible and catastrophic outcomes for billions of people and many future generations on Earth," the institute said.

Levke Caesar, a climate physicist at PIK and a co-author of the report, said ocean acidification is getting worse everywhere, but is especially bad in the Southern Ocean and the Arctic Ocean.

One of the nine factors, which relates to the planet's protective ozone layer, is no longer an immediate worry because chemicals that had been damaging it were banned in 1987.

The six factors that the PIK says have exceeded the safe level are: climate change, the introduction of novel entities, change in biosphere integrity, modification of biogeochemical flows, land system change, and freshwater change.