Ocean Acidifying at Faster Rate than in Past 300 Million Years

March 2, 2012

The single-celled organism Stensioeina beccariiformis survived the asteroid impact that killed the dinosaurs 65 million years ago but went extinct 9 million years later, when the oceans acidified due to a massive CO2 release. It ranged across many depths, in all oceans. (Credit: Ellen Thomas)

Science Daily: 

The world’s oceans may be turning acidic faster today from human carbon emissions than they did during four major extinctions in the last 300 million years, when natural pulses of carbon sent global temperatures soaring, says a new study in Science. The study is the first of its kind to survey the geologic record for evidence of ocean acidification over this vast time period.

“What we’re doing today really stands out,” said lead author Bärbel Hönisch, a paleoceanographer at Columbia University’s Lamont-Doherty Earth Observatory. “We know that life during past ocean acidification events was not wiped out — new species evolved to replace those that died off. But if industrial carbon emissions continue at the current pace, we may lose organisms we care about — coral reefs, oysters, salmon.”

The oceans act like a sponge to draw down excess carbon dioxide from the air; the gas reacts with seawater to form carbonic acid, which over time is neutralized by fossil carbonate shells on the seafloor. But if CO2 goes into the oceans too quickly, it can deplete the carbonate ions that corals, mollusks and some plankton need for reef and shell-building.


Oceans get more acidic when more carbon gets into the atmosphere. In pre-industrial times, that occurred periodically in natural pulses of carbon that also pushed up global temperatures, the scientists wrote.

Human activities, including the burning of fossil fuels, have increased the level of atmospheric carbon to 392 parts per million from about 280 parts per million at the start of the industrial revolution. Carbon dioxide is one of several heat-trapping gases that contribute to global warming.

To figure out what ocean acidification might have done in the prehistoric past, 21 researchers from the United States, the United Kingdom, the Netherlands, Germany and Spain reviewed studies of the geological record going back 300 million years, looking for signs of climate disruption.

Those indications of climate change included mass extinction events, where substantial percentages of living things on Earth died off, such as the giant asteroid strike thought to have killed the dinosaurs some 65 million years ago.

The events that seemed similar to what is happening now included mass extinctions about 252 million and 201 million years ago, as well as the warming period 56 million years in the past.

The researchers reckoned the 5,000-year hot spell 56 million years ago, likely due to factors like massive volcanism, was the closest parallel to current conditions at any time in the 300 million years.

During the warming period 56 million years ago, known as the Paleocene-Eocene Thermal Maximum, or PETM, and occurring about 9 million years after the extinction of the dinosaurs, acidification for each century was about .008 unit on the pH scale, Hoenisch said.

Back then, many corals went extinct, as did many types of single-celled organisms that lived on the sea floor, which suggests other plants and animals higher on the food chain died out too, researchers said.

By contrast, in the 20th century, oceans acidified by .1 unit of pH, and are projected to get more acidic at the rate of .2 or .3 pH by the year 2100, according to the study.

The U.N. Intergovernmental Panel on Climate Change projects world temperatures could rise by 3.2 to 7 degrees F (1.8 to 4 degrees C) this century.

“Given that the rate of change was an order of magnitude smaller (in the PETM) compared to what we’re doing today, and still there were these big ecosystem changes, that gives us concern for what is going to happen in the future,” Hoenisch said.

49 Responses to “Ocean Acidifying at Faster Rate than in Past 300 Million Years”

  1. Seems Maurizio’s talents lie entirely in trying to steer the discussion away from what is relevant and topical. As for “inventing” stories, pretty smug to assume I hadn’t already Googled you and found that 1-5 pretty much nailed it (your nonsensical, unsubstantiated protestations to the contrary notwithstanding).

    Smug in another way, as well: I was writing in response to Peter’s discussion of how disassociated from the human reality of climate change denialists are, and you ASSumed I was speaking about you.

    Hate to break it to you, but this blog and the topic it’s centered on? Yeah, it ain’t about you.

    So bugger off already and busy yourself telling everyone how overfishing isn’t an issue and there’s nothing to worry about.

  2. (Of course, if you feel that my suggestion that you do seem to fit that bill is so offensive, a substantiation of your core position on AGW and a refutation of my guess about you here would be welcome. I’d happily admit my take on you incorrect if it turns out you’re actually a happy climate change prevention warrior who is deeply committed to climate change impact mitigation and carbon emission reduction. Please, prove me wrong–but do so not with your mere and naked say-so, but rather you know…actual empirical evidence.)

  3. g2-b31f1590b0e74a6d1af4639162aa7f3f Says:

    If Greenman were a shift-manager at Burger King, he’d probably be repeating that line over and over again as he tried to train you to work the counter.

  4. The trouble MorinMoss is that I’m sure if we started investigating we’d come against a very strange definition of “vile” on your side. That’s normal, just as it is normal for legions of globalwarmists to consider my utterances as “spam” just because they don’t find me as fired up by the Sacred Cause as they are.

    • MorinMoss Says:

      A quick glance at various threads shows that your posts evince more polite replies than, for example, R Gates’ does at WUWT

      I’ll find some concrete examples of both sides later but duty calls.

      And, kudos for playing coy, but you know quite well what I mean.

  5. Google “agw debate-challenged game omniclimate” to see what I managed to collect from an archwarmist site I shall not name.

    • Stop polluting the Internet with denialist nonsense, and people will probably quit calling you a denialist.

      They might still call you a poophead. Not much can be done about that.

  6. […] time in the Earth’s history; and we are now witnessing ocean acidificationa at a similarly unprecedented rate: Thus, ecologists like Peter Sale (and many others) warn us that we are perilously close to the […]

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