- a 2015 study found there is no techno-fix to prevent a catastrophic collapse of ocean life for centuries if not millennia if we continue current CO2 emissions trends through 2050.
A study published in May 2017 tells us that oxygen is depleting in the oceans two or three times faster than expected.
- by combining oxygen loss with ever-worsening ocean warming and acidification, humans are re-creating the conditions that led to the worst-ever extinction, which killed over 90 percent of marine life 252 million years ago.
Wikipedia on the Permian–Triassic extinction event:
- The Permian–Triassic (P–Tr or P–T) extinction event, colloquially known as the Great Dying, the End-Permian Extinction or the Great Permian Extinction, occurred about 252 Ma (million years) ago, forming the boundary between the Permian and Triassic geologic periods, as well as the Paleozoic and Mesozoic eras. It is the Earth’s most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct. It is the only known mass extinction of insects. Some 57% of all families and 83% of all genera became extinct. Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event, possibly up to 10 million years.
Then as now the problem started on land, that time with severe volcanism. However, then too methane clathrates became involved. We don’t really know whether it will be worse or better this time, but what we are heading for looks so bad that it doesn’t really matter.
- As National Geographic reported in 2015, we’re already starting to see the impacts of anoxia. “The waters of the Pacific Northwest, starting in 2002, intermittently have gotten so low in oxygen that at times they’ve smothered sea cucumbers, sea stars, anemones, and Dungeness crabs,” the magazine reported.
That article goes into the complex factors at work, and there is a variety of scientific opinion:
Many scientists already suspect global warming is partly to blame for this transformation. Deutsch and others, however, think oxygen declines so far have been driven by complicated natural factors. Ocean conditions vary so much normally that they might be experiencing an unusual period of depletion—one that could moderate soon.
But Deutsch called that “a very, very thin silver lining.”
The larvae of strange but important midwater fish like the black sea dragon have declined off California as low-oxygen regions have expanded.
“Right now in the ocean, there is incredibly strong internal variability and a very tiny climate trend on top of it,” he says. “But my sense from all the model simulations we’ve done is that we’re on the verge of having that trend emerge from the noise.”
The simple fact remains, however, that warmer waters hold less oxygen and anoxic zones are appearing and growing at an alarming rate. This image gives some idea:
The black patches represent incomplete data.
The 2017 study has raised the level of alarm finding that ocean oxygen was falling more rapidly than the corresponding rise in water temperature. It pays to take notice of Hans Joachim (John) Schellnhuber, Director of the Potsdam Institute for Climate Impact Research, Professor for Theoretical Physics at the University of Potsdam, Senior Research Fellow at the Stockholm Resilience Centre, and Member of the German Advisory Council on Global Change (WBGU):
- If we don’t start slashing carbon pollution, then, as co-author John Schellnhuber put it, “we will not be able to preserve ocean life as we know it.”
Now it looks as though we are Losing Nemo. Increased acidification robs clownfish of their hearing and sense of smell. Presumably other species will be similarly afflicted.
The Permian–Triassic extinction event included about 60,000 years of acidic oceans. On land whether Homo sapiens survives may be put to the test. However, in the long run not all may be lost. Mammals in their modern for really started their journey about 30 million years after the Great Dying. When given a chance mammals diversify quite quickly, so some millions of years down the track another species that is wise as well as clever may appear.