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The Forum > Article Comments > Warming's hidden danger > Comments

Warming's hidden danger : Comments

By Julian Cribb, published 30/11/2007

Acid oceans are the elephant in the room of global change: a phenomenon with potentially enormous implications for our planet.

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It would take more fossil fuels than exist on earth to push the pH of the entire ocean below the neutral point of 7.0.

When the issue of greenhouse pollution was first mooted in the 1930s, it was immediately dismissed because it was understood that the oceans would dissolve far more CO2 than we could ever produce, leaving atmospheric levels barely elevated (and the ocean barely less alkaline).

Yet atmospheric CO2 levels were observed to rise over the next two decades nevertheless; it was only in 1959 that this was explained: surface waters 'acidify' and absorb far less CO2 than the ocean might as a whole. The deeps circulate to the surface only over a slow 600-1000 year cycle, and so far carry no additional CO2.

The surface layers of the ocean have absorbed about 40% of total anthropogenic carbon dioxide emissions, with plant growth taking up another 10% or so.

But 'Acidified' surface waters now take up less CO2; the rate of dissolution decreases year-on-year and so atmospheric CO2 levels are rising faster than we might otherwise have expected.

It is this faster accumulation of CO2 in the atmosphere that is really alarming, because it brings closer the potentially-disastrous tipping point of Siberian thaw (which is expected to release large quantities of methane) and other positive feedbacks from elevated temperature. A slightly warmer as well as 'acidified' surface ocean could stop absorbing CO2 on average, meaning it wouldn't get any more acidic and may even release some dissolved CO2.

The greatest threat of abrupt positive-feedback-driven climate change is that temperature change may disrupt world-wide rainfall patterns, causing unpredictable droughts and floods which would wreak havoc with the agriculture on which 6 billion people depend.

And the crucial tipping point is roughly a 2-degree warming. This is potentially far, far closer than the 2100-2200 timetable of surface ocean acidification beginning to interfere seriously with oceanic ecosystems.

It is agriculture and humanity we must act to save, before the tundra melts and long, long before the Great Barrier Reef dissolves in acid.
Posted by xoddam, Friday, 30 November 2007 11:47:39 AM
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“Today the scientific evidence clearly indicates the surface oceans are already acidifying and the effects of this can be seen in corals and other organisms.” Julian says, referring to Malcolm McCulloch, a peer-accepted specialist in these matters.

Utterly alarmist, you can be sure: Nigel Lawson (British Chancellor of the Exchequer 1981-9) can tell us so. He is out here to ginger-up us colonials on such issues with the help of a think(or non-think?) tank or two, and ABC Radio National’s “Counterpoint” broadcast today 30.11.2007. Worth tuning in to, in the style of “and you’ll hear bible stories that you’ve never heard before” – if you have so far been plugged into only the scientific data itself.

Acidifying oceans - we “should be putting maximum scientific effort into understanding it”. Not a bad idea. Nor is taking precautionary action immediately, just in case this gigantic experiment with the oceans is a bit crook – otherwise we could go the way of the trilobite. Somewhat earlier than necessary. Alas poor trilobite – in the oceans you did dwell; but climate change did make things strange. Now 'tis only your fossils we know well.
Posted by colinsett, Friday, 30 November 2007 2:24:26 PM
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An excellent article from Julian!

"Finding out whether the burning of fossil fuels is killing sea life and how this will affect all life on earth is even more important and urgent."

True, however, we already know that oil slicks kill marine life and sea birds. We know that the oceans are full of debris (including radioactive junk and bio-accumulative chemicals.)

We know that dead whales have washed up on our Australian shores with their entire bellies filled only with plastic bags and we know that additional PCB's, dioxins and furans have invaded the Arctic ice-caps, the marine life there and the Inuits.

We know from official reports that industrial CO2 in Australia is increasing every year despite the spin from governments and industry.

We also know that the motor vehicle industry emits more CO (combusting to CO2) than any other industry.

We know very well that our eco-systems are seriously polluted by man.

Why not observe the massive deaths occurring in sea birds (also native birds) who depend on oceans for survival? Our environmental regulators like to describe these catastrophes as "natural phenomonen."

Our feathered friends are desperately trying to get our attention.

And those who express concern because of their observations are chastised by those who govern with:

"It's the economy stupid."

Surge of Dead Seabirds Alarms Scientists (USA)

4 July 2007

"Hundreds of dead seabirds that washed up along the Southeast coast in recent weeks apparently starved to death, but experts don't know why. The deaths of the birds - similar to gulls and called greater shearwaters - have wildlife officials worried about possible changes in the ocean that could have affected the fish that the birds usually eat.

"An estimated 1,000 of the dead birds have been found from the Bahamas to Florida and north to the Carolinas. About 160 have been found along the South Carolina coast from Hilton Head to Murrells Inlet.

"The birds, which feed on small fish, nest on islands off southern Africa and then migrate north during the summer to the ocean off Canada."
Posted by dickie, Saturday, 1 December 2007 6:44:15 PM
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I respect Julian Cribb for the good work he's done in the past. However, it is scientifically less than honest to say that the oceans are becoming more acid. In fact, they are becoming less alkaline. It may not sound as alarmist as warning that our seas are acidifying but, until pH drops to 7.0, the change to our oceanic water quality is that its alkalinity is lowering.
The other much more serious problem with the picture being painted by Cribb's article is that there have been several times in our geological past when dissolved CO2 has risen to 300 ppm or higher (some references talk about CO2 levels higher than 2000 ppm). Yet marine life has flourished. Corals and other organisms using calcium carbonate to make their shells or skeletons have survived for hundreds of millions of years, in spite of significant changes to water chemistry. I think we are being far too dismissive of nature's ability to cope with environmental change
Posted by Bernie Masters, Monday, 3 December 2007 9:06:43 AM
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I have long remained fascinated by paleontologist, Dewey McLean's hypotheses on volcanoes and greenhouse gases.

Much of his research, as early as the '70s, was to do with the Deccan Traps lava eruptions and the devastation and mass extinction of the dinosaur and other terrestrial life forms.

"In the oceans, warming, and acidification of the upper waters as atmospheric carbon dioxide diffuses into them, can kill life on a massive scale.

"For example, warming of Pacific Ocean waters during modern El Niño events devastate marine life."

" Based on my studies of the impact of greenhouse warming upon life, I believe that a major perturbations of the carbon cycle can trigger transitions in the biosphere from order into chaos, and are the most dangerous phenomenon that life can experience."

We can only pray that we humans do not witness another "Deccan Traps" catastrophe since man-made releases of CO2, radioactive contamination and other eco-destroying pollutants are already tipping us over the edge, without any assistance from natural, catastrophic events.
Posted by dickie, Monday, 3 December 2007 10:52:47 AM
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An article in New Scientist on the effects of CO2 in the atmosphere covered this very well. In the article, the effects of additional CO2 decreases the pH (more acid / less alkaline) which has the effects of making carbonates more soluable.

As coral reefs are essentially built from carbonates, the effects were measured under controlled circumstances. The indications were:

At present levels of CO2, the reefs are already eroding as fast as the corals can build them, at present rates of CO2 emmissions growth the Barrier reef will disappear by 2050. Reductions to Kyoto targets will push this out to maybe 2080, but only a really massive reduction could save them.

This actually came out of a study which was trying to determine why CO2 levels were not rising as fast as scientists had predicted. It was then found that the oceans were absorbing most of the CO2 emitted.

As the ocean is a basic solution the changes in pH would be very small until the reserves of chemicals such as carbonates was consumed. This point has not yet been estimated, but mass extinctions are unlikely to occur before this point.
Posted by Shadow Minister, Tuesday, 4 December 2007 8:23:21 AM
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