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CO2 and the acidification of oceans


Finally, an article (from Associated Press) about a study that speaks to something I’ve worried over and written about for years: the acidification of oceans from CO2 releases. For quite a long time I’ve told people, who view me as a “warming skeptic,” that the science of climate change is not just about whether or not the climate is warming, by how much, and whether or not humans are the cause. That’s the dumbed down “media” version of the issue, and opinions are all over the place on that among scientists.
I was told years ago and have subsequently confirmed that a very serious consequence of our CO2 releases, one that is simply not debatable, is that much of those billions of tonnes of CO2 we are pumping into the air are ultimately absorbed by the ocean and this changes the pH. I’ll let the article below speak for itself, and I’ve provided the link to the scientific study at the end. But I’ll mention just one consequence of even a slightly acidified ocean: the entire food chain of the seas is based on phytoplankton, the microscopic sea creatures that float about in the warm upper layer of the ocean. They make their tiny skeletons from carbon in the water. Over millions of years the carbon from the dying creatures floats to the ocean floor where it accumulates as calcium carbonate (limestone) some of which eventually is pushed up into continents and mountain ranges as the sea floor is relentlessly reformed by continental drift and plate tectonics. This is why marine fossils may be found at the tops of mountains such as the Rockies, and why limestone deposits are ubiquitous in North America, where they’re mined for cement manufacture (among other things). (Before plate tectonics was understood, creationists used to point to the presence of sea creature fossils on mountaintops as evidence of the Bible’s Great Flood. Even Charles Darwin was puzzled about how they got there.)
It’s all about the “carbon cycle” which is very subtle. The earth’s climate and cloud formation is regulated, for instance, in part from the carbon that is gradually worn away by rain from limestone on mountains, that finds its way into rivers and oceans. We’re only beginning to understand this cycle, at the very time we’re altering it by dredging up fossilized carbon that’s accumulated over hundreds of millions of years and pumping it into the atmosphere within only a couple of centuries.
There’s a school of thought that altering the carbon cycle is dangerous not simply because an already-warm interglatial period may become hotter, but because the slight acidicification of oceans will interfere with the phytoplanktons’ (and small creatures like krill) ability to build skeletons and shells, and the entire oceanic food chain and ecosystem will collapse. If this happens, it’s not alarmist to predict that the environmental and social pressures this will triger will lead to the collapse of civilization as we know it. (By the way, if you want the best possible explanation of the carbon cycle in layperson’s terms, I again direct you to the wonderful new book The Revenge of Gaia by James Lovelock, which completely changed by outlook and life.)
Now here’s the article:
Fossil fuels said to damage ocean life
By RANDOLPH E. SCHMID, AP Science WriterWed Jul 5, 2:08 PM ET
Corals and other marine creatures are threatened by chemical changes in the ocean caused by the carbon dioxide from burning fossil fuels, a panel of scientists warned Wednesday.
Already blamed for a greenhouse effect warming of the climate, much of this added carbon dioxide is dissolving in the oceans, making them more acid.
Such a change can damage coral and other shells and sealife, according to the panel of researchers convened by the National Science Foundation, National Oceanic and Atmospheric Administration and U.S. Geological Survey.
“A most fundamental property of ocean chemistry, pH, is changing and will continue to change as long as CO2 emissions are increasing. That is not debatable,” Joan Kleypas, the report’s lead author and a scientist at the National Center for Atmospheric Research in Boulder, Colo., said in a briefing.
The pH scale measures how acid or alkaline a substance is, rating from 0 to 14 with 7 being neutral. The lower the number the more acid something is.
“In the oceans pH is a relatively constant property and it has not changed over time scales of hundreds of thousands and probably even millions of years,” Kleypas said.
“The pH changes that are occurring in the ocean today are truly extraordinary,” she added. The oceans are normally slightly alkaline. Their average surface pH was 8.2 in 1800 and is headed for a predicted 7.9 by the middle of this century, she said.
“But we are only beginning to understand the complex interactions between large-scale chemistry changes and marine ecology. It is vital to develop research strategies to better understand the long-term vulnerabilities of sensitive marine organisms to these changes,” Kleypas said.
The researchers estimated that between 1800 and 1994 the world’s oceans absorbed 118 billion metric tons of carbon, reducing the natural alkalinity of seawater. A metric ton is 2,205 pounds.
Richard Feely, an oceanographer at NOAA’s Pacific Marine Environmental Laboratory in Seattle, said “this is leading to the most dramatic changes in marine chemistry in at least the past 650,000 years.”
Chris Langdon at the University of Miami said studies show that coral calcification consistently decreases as the oceans become more acidic. That means these organisms will grow more slowly, or their skeletons will become less dense, a process similar to osteoporosis in humans. That threatens reefs because corals may be unable to build reefs as fast as erosion wears away the reefs.
Ocean acidification report:
http://www.ucar.edu/news/releases/2006/report.shtml


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