Oceans Now Face a ‘Triple Threat’ of Oxygen Loss, Extreme Heat and Acidification

The triple threat of extreme heat, deoxygenation and acidification can last for as long as 30 days. The study also found that these water column-compound extreme events tend to occur in high latitudes and the tropics and can reduce habitable space by as much as 75%.

A new study has found that our planet’s oceans are not only becoming warmer due to climate change, but are losing oxygen and becoming increasingly acidic as well. The study, published in AGU Advances, found that about a fifth of the world’s ocean surface is vulnerable to this ‘triple threat’ hitting it at the same time.

“The global ocean is becoming warmer, more acidic, and losing oxygen due to climate change. On top of this trend, sudden increases in temperature, or drops in pH or oxygen adversely affect marine organisms when they cannot quickly adapt to these extreme conditions,” the study writes. “These conditions are worse for marine organisms when such extremes occur together in the vertical water column.”

“Marine extreme events such as marine heatwaves, ocean acidity extremes and low oxygen extremes can pose a substantial threat to marine organisms and ecosystems,” the study added. “Such extremes might be particularly detrimental when they are compounded in more than one stressor.”

The study notes that human-induced climate change, such as the burning of fossil fuels, is the cause of this ‘triple threat’. And not only are the effects of these phenomena grave, but they now last three times longer and are three times more intense than that of the early 1960s.

“The heat has been literally off the charts, it’s been astonishing to see,” said Andrea Dutton, a geologist and climate scientist at the University of Wisconsin, who was not involved in the study.

When our oceans are subjected to excessive amounts of carbon dioxide, that carbon leads to an increased level of ocean acidity while also depleting oxygen levels. This creates a disastrous affect on marine life and their homes; and in some instances, can dissolve the shells of marine organisms.

“Marine life is being squeezed out of places it is able to survive,”.This paper makes clear that this is happening now and that these compound threats will push organisms past their tipping points.

“People have to recognize that oceans have been buffering us from the amount of heat we have been feeling on land as humans, but that this hasn’t been without consequence.”