Why That's Certainly Slimming

Only not, perhaps, in a good way. We, mankind, us, you, me - have so f#@ked up our oceans that the creatures who call them home are in a world of woe. That translates into real change. By the end of the century scientists warn that Atlantic Cod in the Barents and Baltic sea could be just one quarter of their current size. The culprit this time? Acidification, the aquatic scourge of our greenhouse gas emissions.

We're doing a lot to redecorate the marine habitat. Plastics, we all know about that. An ocean of plastics. Marine pollution, the toxic runoff of man-made chemicals into coastal waters now triggering oceanic dead zones where fish swim in and don't swim out. Add over-fishing and seabed mining and deepwater oil drilling. And then there's the warming, our heating waters that are driving marine migrations and killing off creatures that can't migrate such as coral. All of that stuff is really lousy but it doesn't hold a candle to ocean acidification which, just in case you're interested, may kill off marine life but, eventually, it will kill us too.

Climate change denialists like to argue about temperatures and such but, like vampires and the noonday sun, they crawl back into their crypts when the conversation gets around to our oceans. That's because the marine science - oceanography, hydrology, marine biology, chemistry and physics - well they're as brilliant as the noonday sun and as hard as concrete. And one of the facts not up for debate is how rapidly our oceans are turning acidic from absorbing atmospheric CO2.

Ocean acidification is progressing rapidly around the world, new research has found, and its combination with the other threats to marine life is proving deadly. Many organisms that could withstand a certain amount of acidification are at risk of losing this adaptive ability owing to pollution from plastics, and the extra stress from global warming.

The conclusions come from an eight-year study into the effects of ocean acidification which found our increasingly acid seas – a byproduct of burning fossil fuels – are becoming more hostile to vital marine life. 

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Peter Thomson, UN ambassador for the oceans and a diplomat from Fiji, which is hosting this year’s UN climate change conference in Bonn, urged people to think of the oceans in the same terms as they do the climate. “We are all aware of climate change, but we need to talk more about ocean change, and the effects of acidification, warming, plastic pollution, dead zones and so on,” he said. “The world must know that we have a plan to save the ocean. What is required over the next three years is concerted action.”

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Ocean acidification is another effect of pouring carbon dioxide into the atmosphere, as the gas dissolves in seawater to produce weak carbonic acid. Since the industrial revolution, the average pH of the ocean has been found to have fallen from 8.2 to 8.1, which may seem small but corresponds to an increase in acidity of about 26%. Measures to reduce the amount of carbon dioxide reaching the atmosphere can help to slow down this process, but only measures that actively remove carbon already in the atmosphere will halt it, because of the huge stock of carbon already in the air from the burning of fossil fuels.

Worse still, the effects of acidification can intensify the effects of global warming, in a dangerous feedback loop. The researchers pointed to a form of planktonic alga known as Emiliania huxleyi, which in laboratory experiments was able to adapt to some extent to counter the negative effects acidification had upon it. But in a field experiment, the results were quite different as the extra stresses present at sea meant it was not able to form the extensive blooms it naturally develops. As these blooms help to transport carbon dioxide from the surface to the deep ocean, and produce the gas dimethyl sulfide that can help suppress global warming, a downturn in this species “will therefore severely feed back on the climate system”.

I know, here's an idea. How about we launch an armada of supertankers just full of the highest-carbon ersatz oil that the world should absolutely not be burning at this point? Oh geez, I just slipped out of cognitive dissonance mode again. Okay, that's not such a good idea. It's a really, really terrible idea. 

And here's one other thing you should keep in mind. Ocean acidification is a mass extinction tipping point. Once that tipping point is crossed, nature takes over and it finishes the job. Here's how paleontologist, Peter Ward, sums it up in his book, "Under a Green Sky."

First, the world warms over short intervals of time because of a sudden increase of carbon dioxide and methane... The warmer world affects the ocean circulation systems and disrupts the position of the conveyor currents. Bottom waters begin to have warm, low-oxygen water dumped into them. Warming continues, and the decrease of equator-to-pole temperature differences reduces ocean winds and surface currents to a near standstill. Mixing of oxygenated surface waters with the deeper, and volumetrically increasing, low-oxygen bottom waters decreases, causing ever-shallower water to change from oxygenated to anoxic. Finally, the bottom water is at depths were light can penetrate, the combination of low oxygen and light allows green sulfur bacteria to expand in numbers and fill the low-oxygen shallows. They live amid other bacteria that produce toxic amounts of hydrogen sulfide, and the flux of this gas into the atmosphere is as much as 2,000 times what it is today. The gas rises into the high atmosphere, where it breaks down the ozone layer, and the subsequent increase in ultraviolet radiation from the sun kills much of the photosynthetic green plant phytoplankton. On its way up into the sky, the hydrogen sulfide also kills some plant and animal life, and the combination of high heat and hydrogen sulfide creates a mass extinction on land. These are the greenhouse extinctions.