Expert assessment: Ocean acidification may increase 170 percent this century

In a major new international report, experts conclude that the acidity of the world's ocean may increase by around 170% by the end of the century bringing significant economic losses. People who rely on the ocean's ecosystem services – often in developing countries - are especially vulnerable.

A group of experts have agreed on 'levels of confidence' in relation to ocean acidification statements summarising the state of knowledge. The summary was led by the International Geosphere-Biosphere Programme and results from the world's largest gathering of experts on ocean acidification ever convened. The Third Symposium on the Ocean in a High CO2 World was held in Monterey, California (September 2012), and attended by 540 experts from 37 countries. The summary will be launched at the UNFCCC climate negotiations in Warsaw, 18 November, for the benefit of policymakers.

Experts conclude that marine ecosystems and biodiversity are likely to change as a result of ocean acidification, with far-reaching consequences for society. Economic losses from declines in shellfish aquaculture and the degradation of tropical coral reefs may be substantial owing to the sensitivity of molluscs and corals to ocean acidification.

One of the lead authors of the summary, and chair of the symposium, Ulf Riebesell of GEOMAR Helmholtz Centre for Ocean Research Kiel said: "What we can now say with high levels of confidence about ocean acidification sends a clear message. Globally we have to be prepared for significant economic and ecosystem service losses. But we also know that reducing the rate of carbon will slow acidification. That has to be the major message for the COP19 meeting."

One outcome emphasised by is that if society continues on the current high emissions trajectory, cold water coral reefs, located in the deep sea, may be unsustainable and tropical coral reef erosion is likely to outpace reef building this century. However, significant emissions reductions to meet the two-degree target by 2100 could ensure that half of surface waters presently occupied by tropical coral reefs remain favourable for their growth.

Author Wendy Broadgate, Deputy Director at the International Geosphere-Biosphere Programme, said: "Emissions reductions may protect some reefs and marine organisms but we know that the ocean is subject to many other stresses such as warming, deoxygenation, pollution and overfishing. Warming and deoxygenation are also caused by rising carbon dioxide emissions, underlining the importance of reducing fossil fuel emissions. Reducing other stressors such as pollution and overfishing, and the introduction of large scale marine protected areas, may help build some resilience to ocean acidification."

The summary for policymakers makes 21 statements about ocean acidification with a range of confidence levels from "very high" to "low".

These include:

Very high confidence

  • Ocean acidification is caused by carbon dioxide emissions from human activity to the atmosphere that end up in the ocean.
  • The capacity of the ocean to act as a carbon sink decreases as it acidifies
  • Reducing carbon dioxide emissions will slow the progress of ocean acidification.
  • Anthropogenic ocean acidification is currently in progress and is measurable
  • The legacy of historical fossil fuel emissions on ocean acidification will be felt for centuries.

High confidence

  • If emissions continue on the current trajectory, coral reef erosion is likely to outpace reef building some time this century.
  • Cold-water coral communities are at risk and may be unsustainable.
  • Molluscs (such as mussels, oysters and pteropods) are one of the groups most sensitive to ocean acidification.
  • The varied responses of species to and other stressors are likely to lead to changes in marine ecosystems, but the extent of the impact is difficult to predict.
  • Multiple stressors compound the effects of acidification.

Medium confidence

  • Negative socio-economic impacts on are expected, but the scale of the costs is uncertain.
  • Declines in shellfisheries will lead to economic losses, but the extent of the losses is uncertain.
  • Ocean may have some direct effects on fish behaviour and physiology.
  • The shells of marine snails known as pteropods, an important link in the marine food web, are already dissolving.

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Citation: Expert assessment: Ocean acidification may increase 170 percent this century (2013, November 13) retrieved 20 July 2019 from
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Nov 13, 2013
Oh great, so we'll be struggling with global starvation and economic pandemonium just about the same time the machines are getting ready to take over. Perfect!

Nov 14, 2013
Finally! If only just a small fraction of the money spent by, "scientists" (I use the term loosely here) who are too busy hiding data that is contrary to their hypothesis, & trying to convince us that its getting hotter. (Not in the last decade anyway.)

If just a small percentage of that money could go towards researching, and educating about this VERY REAL side effect of the way we have been polluting our atmosphere with CO2 emissions would be far lower than they are today.

There is literally no disputing that the oceans are more acidic than they were 10, 20, 30 yrs ago. Any idiot with a $1.50 can buy some litmus paper and create his very own data set. We get too much of our food from the ocean to be playing the games we have been.

Off my soap box now, hopefully the next dominant lifeform on this planet is a better steward. (Dolphins maybe?)

Nov 14, 2013
Hey, instead of spending millions studying the problem, how about spending millions adding a mild slow release base to our oceans? A million or so there would no doubt solve the acidification problem, a few thousand tons of CaO?

As long as we're being stupid, why not go in with both feet?

Nov 14, 2013
how about spending millions adding a mild slow release base to our oceans?

I think you don't realize how big the oceans are and that there are currents and circulatory systems in them that make a global (and homogeneous!) release of anything impractical.

All you'd achieve is to kill off a part of the ocean fauna/flora with local too high pH calues.

As long as we're being stupid

No. As long as YOU're being stupid. The rest of humanity (and especially those who know anything about science) are trying hard not to be.

Nov 14, 2013
There you go making those dumb assumptions again.
Why not spend millions addressing the problem instead of studying it? It is feasible to treat the symptoms. Thought the idea is abhorrent, which is what I was going for. Whatsamatter YOU won't get grant money?
As far as local/nonlocal effects-it amazes me you can be so wrong. I don't even know where to start, and since we've had these conversations before... I am not even going to think about it.
Have a nice day.

Nov 15, 2013
I think you don't realize how big the oceans are and that there are currents and circulatory systems in them that make a global (and homogeneous!) release of anything impractical
Perhaps people a little less fatalistic than aa might be looking for practical solutions:

"Sea-grass soak
The panel recommends creating of an "acidity" budget to account for natural and human-influenced sources of acidity; improved methods of forecasting corrosive conditions; and finding ways to use sea grasses to soak up carbon dioxide in shellfish hatcheries."

"ron fertilization of the ocean could stimulate photosynthesis in phytoplankton (see Iron Hypothesis). The phytoplankton would convert the ocean's dissolved carbon dioxide into carbohydrate and oxygen gas, some of which would sink into the deeper ocean before oxidizing. More than a dozen open-sea experiments confirmed that adding iron to the ocean increases photosynthesis in phytoplankton by up to 30 times"

Nov 17, 2013
The ocean is dying and we are killing it. Guess what happens when we figure out that reducing the worlds population drastically is the only way to save it and thus us?

Nov 17, 2013
@Otto-I think they tried the iron seeding... my memory is faulty, but didn't it fail because of some kind of feedback? Sorry, I don't recall.

My point was, the real solution is to stop the ocean runoff to the oceans. It is doable, but, much more expensive than a stupid and abhorrent solution. Neither one is going to happen.

Why not encapsulate farms, so that nothing is wasted? We have plenty of labor and materials to do it. We just don't have the money.

Which is stupid to, but the increasing obsolescence and hinderance of money is another topic, one with psychologists on one side, economists on the other, idiots on the other and the insane on the (-pi)^3/8th side.

Nov 17, 2013
The ocean is dying and we are killing it. Guess what happens when we figure out that reducing the worlds population drastically is the only way to save it and thus us?

They put you at the top of "The List".

Nov 18, 2013
sorry I don't recall
Sorry you don't have to recall. This is the Internet. Look it up.
stop the ocean runoff to the ocean
Sorry my mistake. Using google requires a brain. That's about the most ignorant thing I've ever read here. And per my profile page I've read some very ignorant things here indeed.

Hey they found a smoldering volcano under the antarctic ice - do you think it will melt the whole icecap? I bet you do.

Nov 18, 2013
So much for polite discourse.
The reason I didn't google, check and done, don't care to waste my time again, but since you were so expert, I thought I would ask and respect our opinion.
I guess my brains do need a checking, but I've learned my lesson.

Nov 18, 2013
It didn't work because lack of scale and a spin on the failure. Evidently, there are those who don't want us to do this either...
I don't understand people.
From wiki
Fertilization may sequester too little carbon per bloom, supporting the food chain rather than raining on the ocean floor, and thus require too many seeding voyages to be practical.[15][56] A 2009 Indo-German team of scientists examined the potential of the south-western Atlantic to sequester significant amounts of carbon dioxide, but found few positive results.[57]

The counter-argument to this is that the low sequestration estimates that emerged from some ocean trials are largely due to these factors:[citation needed]
1.Data: none of the ocean trials had enough boat time to monitor their blooms for more than five weeks, confining their measurements to that period. Blooms generally last 60–90 days with the heaviest "precipitation" occurring during the last two months.
2.Scale: most trials used less than 1,000 kilogr

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