So here at last, as promised, is my post about the Global Warming elephant. Now while blogging on these weighty topics I have not hesitated to inject a little sarcasm and humour into my ruminations about the small herd of elephants in my (rather crowded) lounge room. After all if can't have a good laugh what is the point of living? Come to think of it some of the best humour is gallows humour anyway.
However, it is a bit hard to find anything humorous about the Global Warming elephant, which is a very serious and large pachyderm, and not amusing. Not at all.
And before discussing the Global Warming elephant, I will first have to mention its cousin, the Great Carbon elephant.
We humans have always been skilled at manipulating our environment. These skills have recently been greatly amplified with machinery and technology, and we have started to alter some of the great chemical pathways that help construct and maintain the biosphere, such as the phosphorus, nitrogen, sulfur and carbon cycles. In the past when we tinkered with some of the shorter, smaller pathways such as the nitrogen cycle or the sulfur cycle we caused some pollution and/or acid rain.
The carbon cycle however is a long term and massive chemical cycle. The two main components are photosynthesis which removes carbon dioxide from the atmosphere and combustion of the products of photosynthesis which puts carbon dioxide back into the atmosphere. In the past combustion was often a biological combustion, although fire and volcanoes also play a role. The two opposite processes are more or less in equilibrium. However, there is also a vast store of fossil carbon which can add to atmospheric carbon dioxide. When it does so, it disturbs the equilibrium of the carbon cycle. In the past such extraordinary combustion has usually been due to some geological event. Recently however, the extraordinary combustion of fossil carbon has been due to human activities.
The element of carbon is central to the chemistry of life and whole branches of chemistry have been devoted to it. It is like a proverbial (huge) chemical elephant deep down in the very engine room of the biosphere and we are like tiny blind fleas crawling on it's vast bulk.
I am reminded of an old Buddhist parable about elephants. It seems that there were five blind men gathered around an elephant. And when asked to describe the elephant they give different answers:
- The one holding the tail said that an elephant was like a piece of rope.
- The one holding the leg disagreed. He thought that an elephant resembled a large tree.
- The one holding the ear, believed that an elephant was like a large fan.
- But the one holding the tusk begged to differ. He stated that an elephant was more like a large spear.
- And the one holding the trunk was emphatic that an elephant was like a giant snake.
One interpretation of this old proverb is that they were all correct, in a sense. A blind man's impression of an elephant depends very much on which part of the elephant he happens to be holding.
I came to appreciate this in conversations with my father last century. He had studied geology and spent his life working in exploration geology. He seemed to cotton onto the potential threat of carbon dioxide in the atmosphere before I did. He opined that the real threat was "hydrates". If the planet warmed enough for the hydrates to be released then we would be in big trouble. He even said that "some people had suggested exploiting hydrates" (I gathered, by his tone of voice, that he thought it was not a very good idea).
At first I didn't see how this could be a problem. I had studied chemistry and mathematics, and when I head the word "hydrates", I thought "inorganic hydrates". As usual when I thought about geology, I thought about inorganic chemistry. I soon realised that the "hydrates that my father was talking about, were organic hydrates, which, these days, are more often referred to as "clathrates". These are basically pure methane enclosed in a cage of water molecules, stabilised by low temperature and/or high pressure in chilled water in oceans or in permafrost. There are vast quantities stored all around the world and if a substantial portion of them were released it could lead to a highly dangerous super greenhouse warming that would be much more severe than the present warming.
Of course I didn't appreciate this immediately. I was holding a different part of the elephant. I would have been more concerned about things like the pH of the oceans. The pH is a scale used to measure the amount of protons (or acidity) of a body of water. If something has a low pH it is said to be acidic. If something has a high pH it is said to be alkaline. I used to think that there was no danger of altering the pH of the oceans in my lifetime. Although there is a good reason to be concerned about anything that would alter the pH of the ocean even slightly.
I had thought our oceans could resist acidification because of their size. Before long (I thought), humanity will have run out of oil and if we have the common sense to refrain from burning all of the world's coal, there is a good chance that we can kick the fossil carbon habit before there is a significant fall in the pH of the oceans. Or so I used to think.
The most dangerous thing about the current global warming event is that it could trigger the release of clathrates. And if that happened, then we would be in serious trouble.
Since the turn of the century it has been confirmed that the pH of the oceans is now decreasing. And as I said this is something that should worry us greatly, because all biological systems are very sensitive to pH. For example our bodies contain their own mechanism for regulating the pH of our blood. If your body's pH should stray much from 7.4, you will get sick. Very sick! It has been postulated (with good reason) that the pH of the ocean might have been around 7.4 when our mammalian ancestors left the ocean in a previous geological era.
Similarly if the ocean's pH should change the entire planet would get very sick!
As a land based species we have a terrestrial-centric view of our ecology. However three quarters of the surface of this planet is covered by water. Life began in the oceans and the marine ecology is a major player in the carbon cycle. It is the oceans that are the greatest carbon sink (and by corollary the greatest oxygen source) and paradoxically if they break down could become a major carbon source.
Photosynthesis is carried out by small marine organisms. These either go into the food chain, or sink to the ocean floor, and would be one of the sources for the formation of clathrates, since when they decay they form methane.
It is possible to imagine how the oceans could be the driving force behind an extremely rapid global "change of state".
- Carbon dioxide causes global warming. The jury is in on this. There are still a few (so-called) sceptics. But we need to be sceptical of their motives and associations. Release of fossil carbon skews the balance of the carbon cycle and the greenhouse warming that results leads to ice packs and glaciers melting.
- Glaciers and marine ice packs reflect sun. And when the melt they expose (darker) areas of the planet that absorb heat much more rapidly. This leads to a "positive feedback loop", causing even more rapid warming and new warmer currents of water. This may be happening now. It is the most likely explanation for the melting of polar ice, which can be seen from satellite images. It is more rapid than was expected and has caught many observers by surprise.
- As the warming continues, clathrates melt. This leads to massive releases of methane, a highly potent greenhouse gas that leads to a "super greenhouse" event. This becomes a dangerous positive feedback loop, that changes the Earth's atmosphere and climate dramatically.
- Methane quickly breaks down into carbon dioxide and water. Although carbon dioxide is not so potent a greenhouse gas, the much higher concentration of carbon dioxide lowers the pH of the oceans to such an extent that marine photosynthesis slows.
- The oceans are no longer a carbon sink and are a major carbon source. Almost all marine vertebrates perish due to the deadly combination of low oxygen and low pH.
- Ninety-eight percent of all vertebrates become extinct.
One of the frightening things about the above outline is that it could happen very quickly. One year us terrestrial mammals are frolicking in our recent interglacial state, which we all know and love. Then there is sudden switch and we are in the new clathrate melting state, which we should all fear greatly. Furthermore once the change of state occurs it is almost impossible to change it back. Eventually micro-organisms will adapt to the new environment and transform the atmosphere back to another cozy interglacial state but that may be half a million years in the future. A future that our species may not be around to participate in.
This sudden change of state is what is often referred to as a tipping point. The words crisis and catastrophe are often bandied about and over-used in relation to world events. These nouns might be appropriate for something as serious as the Killer Flu Epidemic of 1917 or World War II, or even the far less serious GFC (Global Financial Crisis).
All of this may sound "alarmist". That's because it is very alarming! The scenario outlined above would be a Catastrophe with a capital "C". However the most frightening thing about it is that it might have actually happened about 250 million years ago, at the so called PT boundary event, otherwise known as the Great Permian Extinction. As you might expect with a name like Great Permian Extinction it was a rather lethal event. It was possibly the most significant mass extinction event in our geological history and it could have run the same course as outlined in the above nightmarish synopsis. There is a considerable body of evidence building that this event began with the release of fossil carbon which lead to the subsequent melting of clathrates and ended in the greatest mass extinction of all time.
The IPCC (Intergovernmental Panel on Climate Change) have tried to produce a sober thoughtful assessment of the problem of Global Warming. However, since they are a large bureaucracy and possibly due to anxiety about being labeled as "alarmist", the IPCC have been rather cautious and under-stated the risk. Their best case was a two degree rise in average global temperature. And their worst case was a six degree rise. Early signs seem to indicate that we are well on the way to the IPCC worst case. In fact it may turn out that the IPCC worst case (six degrees warming) may be the best case. The worst case is the hellish scenario above.
Considering the lengths that we go to avoid some minuscule types of risk, any risk of a clathrate super greenhouse would be unacceptable. We should desist from burning fossil carbon. However, the goal of carbon neutrality may not be sufficient. A more prudent course of action would be to make our economy carbon negative. There is plenty of "weird science" that we might try to "engineer" the climate. But some of these projects may jeopardise photosynthesis or they are themselves very energy intensive. The only guaranteed way to achieve a carbon negative economy is with photosynthesis. It is the chemical pathway that has served the earth reliably for billions of years and it runs on sunlight.
One major objection to taking action on global warming is that of "cost". This is clearly absurd. The cost of not taking action is immeasurable. Furthermore the cost of re-engineering our economy would be offset by considerable benefits including employment, training and growth in the areas of new technology. It may prove to be a stimulus that can resurrect our dying economy, poisoned as it is by excess fossil carbon.
In any case the most widely accepted strategy for dealing with climate change is "carbon trading". This was the strategy which the Australian government were proposing, until it was postponed due to the current financial crisis.
The proponents of carbon trading tell us that it will allow a "market based solution". And markets have the place. Provided that they are simple. The best type of market is one where "yer pays yer money and yer makes yer choice". Recently however market advocates have dreamed extremely complex markets. Some of them, like the still smoldering credit markets, are so complex that nobody really understands what it is they are buying and selling.
Unfortunately carbon trading markets were dreamed up by the same people who invented credit default swaps and collateralized debt obligations. You won't find a satisfactory explanation of what emissions trading is because nobody really understands what it is.
What ever approach we take to ending the burning of fossil fuel, it must be simple and direct.
One of the most difficult tasks will be achieving consensus. Companies involved with producing fossil fuel are large and influential, and the role these companies have played in the public arena has been mostly one of obstruction. Vast amounts of money have been spent on confusing, befuddling and misleading the general public and influencing policy makers to prevent them from taking any action. The contribution from these and other corporations who have a stake in the fossil fuel economy, has been quite rightly compared to that from the tobacco companies in regard to the "cancer debate" last century.
In this respect climate change deniers have played a specious role. Because of the complexity of climate systems it is impossible to predict when the "tipping point" will occur. Our ailing fossil fuel economy is driving down a road towards this tipping point which is like a sheer cliff, where the road ends. The climate change sceptics seem to argue that because of the fog of uncertainty that surrounds the cliff we don't have to worry about when to apply the brakes. In any case there are no brakes, and even if there were, the drop is not that great it is just a tiny six inch drop.
But whether it is six inches or six thousand feet, we won't know until we actually go over the cliff.
Our response to global warming should be simple risk-management.
Reference and Further Reading
- This Wikipedia article on the Intergovernmental Panel on Climate Change, gives a brief summary of the more detailed findings of the IPCC.
- The ABC Science Show, Catalyst discusses the threat that clathrates pose.
- Sea sick. Award-winning Canadian journalist Alanna Mitchell discusses her new novel.
- Wikipedia discussion of Ocean acidification.
- The Green Paper, published by the Australian Dept of Climate Change as a result of Garnaut report.
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