I wonder when any global warming sceptic is going to come up with convincing reasons why ocean acidification is not something to worry about. In fact, when are they going to give it any attention at all.Over the history of the planet, there have been many sudden peaks in CO2 related to volcanic eruptions, releases from hydrothermal vents, and other natural events. When the pH of the ocean dips as a result of absorbing this excess gas, bottom sediments rich in calcium carbonate begin to dissolve, countering the increase in acidity. This buffering process occurs over 20,000 years, roughly the time it takes for water to circulate along the bottom from the Atlantic to the Pacific and back up to the surface several times. Currently, however, we are pouring man-made CO2 into the atmosphere at 50 times the natural rate. “That overwhelms the natural buffering system for maintaining balance in ocean chemistry,” the Carnegie Institution’s Caldeira says. “To find any parallel in the earth’s history you would have to look to a sudden violent shock to the system far in the geologic past.”
One such event occurred 55 million years ago at the so-called Paleocene-Eocene Thermal Maximum (PETM), when 4.5 million tons of greenhouse gases were released into the atmosphere. Just what triggered this enormous emission is not known, but scientists suspect volcanic activity may have begun the process. That may in turn have caused the planet to heat up enough to melt deposits of methane frozen in sediments on the ocean floor (something, incidentally, that could happen again), discharging even more potent greenhouse gases into the atmosphere and further heating the planet in an escalating feedback loop.
Whatever the exact cause of the CO2 release at the PETM, the earth warmed faster than at almost any other time in its history. The average temperature soared 9 degrees Fahrenheit, entire ecosystems shifted to higher latitudes, and massive extinctions occurred on land and, most telling, at sea. The abrupt rise of CO2 acidified the oceans. James Zachos, a paleo-oceanographer from the University of California at Santa Cruz, analyzed sediment cores obtained from deep drilling in the ocean and discovered that bottom-dwelling creatures with shells disappeared from the fossil record for a period of more than 40,000 years corresponding to the PETM. And once the oceans turned more acidic, Zachos says, they did not recover quickly: It took another 60,000 years before sediments again began to show a thick white streak indicative of fossilized shells.
Drastic as the PETM was, the event is tame compared with acidification today. “Back then,” Zachos says, “4.5 million tons of CO2 were released over a period of 1,000 to 10,000 years. Industrial activities will release the same amount in a mere 300 years—so quickly that the ocean’s buffering system doesn’t even come into play.”
UPDATE: I've noticed that the figure of 4.5 million tons of CO2 being released during PETM must be an error. If you follow the link in the article (about PETM,) it indicates it should be 4.5 Gt. Disappointing to see an error like that turn up at Discover, but I'll email them now!
From a Message in a Bottle Washed up on a Beach
ReplyDeleteThe report on my imminent death is premature. I have been sloshing around in the basins on the crust for more than four billion years. I now cover nearly 71 per cent of the planet. Since the last ice age, I have lifted myself out of the basin by 120 metres and scared the tribes of Noah to the higher ground. During deep time, I became the universal solvent for the volcanoes and the clouds. I have taken up as much salt as required by local circumstances and sometimes give it back in hot shallows and desert areas of my world. I have given man the salt in his blood. I have absorbed as much gas as I need to maintain balance with the organic world within me and on land. Your CO2 output is infinitesimally small. The exchange is so peaceful that science calls it equilibrium. I can absorb more CO2, if the plants do not need it, and it does not give me acid imbalance. My pH will remain basic no matter what you say. The variations you measure have come and gone many uncountable times on the planet and your baseline is too small to know the truth. What you do not get is that warming of the oceans releases CO2 and other gasses from my water, while cooling my water allows me to take up CO2 in vast amounts to nestle with the other molecules in my coldest most remote realms. I can absorb all that man can produce because your impact is feeble compared to my capacity.
Please watch me with humility for you cannot change me. I am the ongoing sink for the planet, and I am huge and my heat content is beyond your estimation. Measure me here and there with your microscopes but know that I will never be that way in that place again. Open your mind to the infinite cycles of chemistry and physics and kneel on my beach. You can only hurt me by not respecting my infinite ability to change chemistry and temperature in all the corners of the seas. My CO2 feeds your plants and your plants provide all the oxygen you breathe. Your base line is infinitesimally small yet your mouth is wide open. Stop sending me your plastic water bottles.
Poseidon, the King
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I am mostly invisible, but not space. I am the wind you breathe, the 20 km thick shell around your sphere. I am bigger than Poseidon’s realm by many times. I am oxygen, and I am 80% nitrogen. I am both water vapour and humidity. I am carbon dioxide, methane, laughing gas and ozone. Argon, neon helium, and hydrogen make my fireworks in the lightening. I heat you by convection like an oven, cool you with my wind chill, and bury you in my microscopic hexagonal crystal frost. From the poles to the equator and from your caves to Kathmandu, I cover you, feed, and water you and your plants: no wind, and there is no food worth eating, for plants or man. Over four billion years and more, I practiced my cycles. My ozone protects you from your sun’s blue rays; my methane warms your coldest nights. Your green plants whirl out my oxygen all night trading it for my CO2 in the sunshine. When you walk in your forest, be thankful for the bargain.
Without my parts per million CO2, you would choke. Without my parts per million CO2, you would freeze. As your people grow in numbers and size, I need more CO2 to fertilize your food. In my opinion, the more fat children, the merrier, because the earth does not laugh enough. Do not pump my CO2 underground or earth will quake from the wrong as it did under Denver on August 9th1967. When you sequester, be prepared to scavenge for food, and perhaps burn your oxygen for warmth
I am Aeolus
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Vulcan - god of fire said, “All the gasses from the mantle of the earth drive my fire and push up my liquid rock. Water affects my temper. When I foam, I am deadly. My carbon dioxide is colourless, and difficult to detect. It is heavy. It sinks and has killed many camped near Lake Nyos, in Cameroon. My sulphur dioxide is a killer too. At more than 20 ppm, it irritates, burns your eyes and is dangerous to breathe. When inhaled, most becomes sulphuric acid. My hydrogen sulphide is easy to smell, like rotten eggs. People are generally able to notice the odour; it can kill you at 50 ppm. My radon is colorless, odourless, tasteless, and radioactive. It can creep into your basement. My hydrochloric acid is colorless, but with an ‘acidic’ odour and taste, My HCl is common around blowholes and in eruptions. It can and will destroy the ozone when it blows to the top of the atmosphere. Just like the liquid acid, my vaporous acid will burn anything it touches - especially the breathers. My sulphuric acid comes in shades of brown and is odourless; exposure results in quick burns and dissolves the outer layers of the teeth. However, my worst most painful acid is hydrofluoric. It is also invisible and will cause deep burns and permanent blindness if not flushed with water. Death by hydrofluoric acid is horrible. Ask the people of Iceland in 1783.
My chimneys are scattered around the planet and one big puff like Krakatau or Pinatubo can ruin your air and cool your world. Between expulsions, my gasses are usually scattered. You will never know when I will speak and kill you because your lives are too short. My CO2 is my most benevolent gas, and I have given you parts per million for you to feed your plants. Use it carefully and do not abuse it. It is weak to fear me and not prosper. I come when I want.
I do not respond to human sacrifice.”
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Finally, Gaia – the earth element said:
“Among the ancient elements of Aristotle, the earth element was both cold and dry. He thought I occupied a place between water and fire. Aristotle lived a short span, just a moment ago in universal time, and he did not ask me. I am wet and dry, hot and cold, light and dark in all the rainbow colours. Gaia is rich and overflowing with goodness. My sphere vibrates with the gravity of the solar system. I ring like a bell when I quake, and if gravity dropped me, my sphere would splash like a tear. When my skin slides, I create wealth and prosperity in your copper mines. You dress to match me at your atomic scale with treasures from your tiny mines.
I must admit, your choices of where to cluster astonish me. I guess you do not know me yet.
I condensed more than four billion years ago as stardust gathered at my core. In all that time continuing tomorrow, I am sorting out the stardust into separate useful solids and liquids. I give most of the vapours to Vulcan and Aeolus and most of the fluids to Poseidon and they all share.
So far, you have found only enough gold to fill one house and enough diamonds to fill one truck. There is more where that came from. Find where I have hidden it in the mountains and under the waters. It is good for you to quest - good luck.
Man is late to the life that began in the salty wet clay. You have the salt of Poseidon, the gills of fish, and the brains of monkeys; you have the muscles of babies and the lips of giants. Your eyes magnify everything and what you see scares you. You must place your optical illusions in the perspective of prosperity, health, food, shelter, and clothing. Please listen to your science and not your demagogues . Your footprint is light. How many of you have seen a mine or a well? None! They are rare like diamonds.
Do what you need to do. Make all your people happy. You have wit enough to do it cleanly. Dig my coal and burn it; make it into plant food again and water. Pump my oil and burn it. There is more where you have not looked. There is much where you have already looked in billion tonne layers of rock in Colorado. It is for man to use and recycle. Do not hesitate to scratch me; I do not bleed; I give.
I do not want to be alone. Gaia and man belong together, and you do not know why. Much of my surface is empty of man. Perhaps illusions are the answer to the riddle. There is always more room for the children. Oh yes, the sunspots will be back when the lying stops. ”
Demagogue - a political leader who gains power by appealing to people's emotions, instincts, and prejudices in a way that is considered manipulative and dangerous.
ReplyDeleteThe authors make an assumption that CO2 is the cause of PET event. The thermal event may have had an extraterrestrial cause and the CO2 and resulting pH drop,may have been the effect. Ice core date appear to show the opposite of the Gore hypothesis. Warming first, then CO2 degasses from the oceans (or methyl hydrates) because of retrograde solubility. Ask yourself who reviewed the article before publication. An independent qualified person should have caught that possibility.
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