Gaia Hypothesis Evidence page three (of three)

page three (of three)
OXYGEN LEVEL
The CO₂ level is controlled by the combined activity of all organisms and so we would expect the same to be true of oxygen. The role of enzymes would be to ensure that oxygen is maintained at the equilibrium level. When organisms sequester carbon or modify the sequestered carbon they also affect the oxygen level. If carbon is stored as carbohydrate the ratio of carbon to oxygen (C/O) is 1/1. When stored as bicarbonate or carbonate the ratio is 1/3. As coal is almost all carbon the ratio is over 1/ million. If this does not give nature enough degrees of freedom to juggle optimum levels of CO₂, oxygen, and ocean pH then she has more degrees of freedom via the decomposition of water and storing the hydrogen in the bicarbonate ion or hydrocarbons or even allowing the hydrogen to escape into outer space. To determine the number of degrees of freedom actually needed is not easy because all the mineral cycles are linked together and there are about forty elements used to build most organisms. However it would not be that difficult to model the movement of the major eight elements to infer how oxygen is maintained at a constant level. If one enzyme can successfully maintain CO₂ then perhaps only one is needed for oxygen. Is this enzyme(s) in denitrifying bacteria, nitrogen fixing bacteria, bacteria that convert cellulose to peat or is it somewhere else. To my way of thinking six or less enzymes would give ample control. While it is possible to paint a picture using three primary colours what is to stop nature using a broader palette if one is available?
OCEAN pH
It has been thought that ocean pH can drop quickly because volcanoes or fossil fuel combustion can rapidly release enormous quantities of CO₂ into the atmosphere, but the raising of ocean pH is slow because the weathering of minerals is a slow process. In other words the ocean becomes acidified by CO₂ moving from the atmosphere into the ocean but the ocean becomes alkaline by the movement of bicarbonate ions from land into the sea. This logic ignores the action of algae which have the potential to rapidly elevate ocean pH. When algae die and sink, or is it sink and die, they take carbohydrates and hydrocarbons to the bottom, they have extracted CO₂ from the upper layer of the ocean raising the pH. If ocean photosynthesis is around 90 Gt (carbon) and if 15% to 20% of this, sinks to the deep ocean, then around 16 Gt of carbon can sink annually. Now, depending on how much of this carbon is being respired, there is the possibility for a very rapid rise in pH. Nature therefore has a fairly powerful weapon in manipulating ocean pH. Unfortunately we know very little about what factors affect the ecosystems responsible for the respiration of ooze on the seabed. The history of the last 50 years has seen ocean pH fall. It would seem that nature has not dramatically reduced ooze respiration at this stage.
Ocean pH is mostly affected by seven general classes of reaction. ONE
Solution of CO₂ into ocean water
CO₂ + OH^- ----> HCO₃^-     pH moves down
TWO
Formation of carbonate skeletons
2HCO₃^- + Ca⁺⁺ ----> CO₂ + CaCO₃ + H₂O     pH moves down
THREE
Ooze formation
HCO₃^- ----> OH^- + CO₂ The gas is used in photosynthesis and ends up as ooze on the sea floor.     pH moves up.
Of the seven reaction styles controlling ocean pH only reaction ONE is not under the control of the DNA in living systems. The rate of reaction TWO is at the mercy of the DNA of reef communities. Reaction THREE is under the supervision of the many ocean algal communities.
FOUR
CaO + CO₂ ----> CaCO₃     pH moves up
FeO + CO₂ ----> FeCO₃
MgO + CO₂ ----> CaCO₃
Here micro-organisms in rocks, using CO₂ oxidise minerals such as feldspar. Traditionally this reaction has been considered as chemical weathering but now we know better. It was not connected with ocean pH. However any reduction in atmospheric CO₂ will ultimately affect the balance of CO₂ in the ocean. In addition reaction FOUR is followed by reaction FIVE. FIVE
CaCO₃ + CO₂ ----> Ca⁺⁺ + 2HCO₃^-     pH moves up
Similarly for the other carbonates. Here micro-organisms attack carbonate and send the calcium and bicarbonate ions into the ground water and off to the ocean. Reactions FOUR and FIVE are not the result of any civic duty that micro-organisms have toward balancing ocean pH, these reactions constitute their energy supply. However, if the reactions are catalysed by enzymes that are rate sensitive to CO₂ then we have more evidence in the vindication of GAIA theory. So we need to set up an experiment to see if reactions FOUR, FIVE and similar reactions accelerate with higher CO₂ levels.SIX
CO₂ + CaSiO₃ ----> CaCO₃ + SiO₂     pH moves up
Similarly for other silicates. Micro-organisms attack silicates.
SEVEN
2KAlSi₃O₈ + 3H₂O ----> Al₂Si₂O₅(OH)₄ + 2K⁺ + 2OH^- + 4SiO₂     pH moves up
This and similar reactions probably involve micro-organisms, the ions flowing in ground water to the sea.
Obviously, if Gaia is any sort of reasonable theory, these reactions will be under enzymatic control and like rubisco they will be rate-sensitive to CO_2. However do not necessarily expect all of them to be ramped up by CO₂, some may be negatively geared. I personally would anticipate a positive gearing but who knows?
WATER VAPOR AND CLOUDS
The greatest unknown factor in any climate model has to be cloud cover. Clouds have enormous control of our weather. The problem is that we are quite ignorant about cloud formation. To what extent is cloud formation biologically controlled? What are bacteria doing in clouds? What is their energy supply? Do they consume dimethyl sulphide or is it just a site for condensation of ice or water?
TERRAFORMING
It has been suggested from time to time that mankind could terraform Mars, so that humanity could slip across to the red planet when the Earth became too hot. The idea is to genetically engineer a few bugs; zip them over to Mars; spread them around; wait a few thousand years and presto: one planet ready for habitation. Contrast this with our Earth, terraformed for the perfect climate, over a period of 4.5 billion years using around 50 million species. Perhaps the complexity of terraforming a planet has been underestimated. Perhaps also, it has been forgotten that Mars does not have a large magnetic field and is not able to retain much of an atmosphere.
REPRODUCTION AND THE BEGINNING OF LIFE
A possible stumbling block to our understanding of the origin of life arises from the imprecise definition of the word reproduction. Most of us would think of reproduction as a discrete process that either occurs or does not. However this concept robs us of the chance to think laterally. Growth is more or less the same concept as reproduction. When a yeast cell buds it appears to be just extra growth. We announce that reproduction has occurred when the bud separates from its parent and becomes autonomous. So a nanometre of space is the only difference between growth and reproduction.

The first 'organisms' did not need to reproduce they only needed to be able to grow. They did not even need to be complete organisms. This is how I see the beginning of life. Chemical compound A is able to grow by combining with source compounds R, S and T from the environment. In the process it releases compounds U and V. Chemical B is able to grow by absorbing U,V and X from the environment and releasing R, S and T. So we can see that growth of species A helps species B and vice versa. This logic overcomes two mental hurdles: How did such complicated things as cells arise and how did early life solve all of its own problems by itself. Obviously cells did not need to develop until after most cellular processes had already developed and early life did not have to solve its own problems but just contribute to the environment in some small way. This is the same way that human society works. Each of us makes a small contribution and in return we enjoy the effort of other peoples' labour.

Question to see if you are awake. In the above scenario, when does growth stop?
JUNK DNA
Sexual recombination of genes is the source of most diversity but mutation is also a source of new variations upon which natural selection directs evolutionary change. Plant biologists use x-rays and teratogenic chemicals to deliberately increase the rate of mutation. The process is very hit and miss. A much more efficient process involves the splicing in of desirable genes. If man can do it, then nature probably discovered it first. The idea that point mutation is the chief source of new genes might not be correct. While point mutation is a source of new variants, jumping genes offer a much faster method of producing functional new genes. Junk DNA offers a storehouse of ready-made prototypes for jumping genes to use.
THE UNSEEN THEORY
Why was Gaia not embraced for so long? Lovelock saw Gaia on cue. The question is why was he alone and more obviously why was mainstream science so slow to catch on? Personally, I think the problem lies within our language. In my mind I had the idea that competition and cooperation were two equally valid processes that were mutually exclusive. I no longer think this way. In a system, all the parts must cooperate together, that is, each part must do its job. It is not possible to have a system where the parts do not cooperate. So cooperation is the very heart of systems.

Competition by contrast, can be part of a functioning system, but it is not essential. Competition helps systems to evolve and become better at what they do, but all competition occurs within the context of cooperation. In sport the players obey the rules, or the game makes no sense. In business, firms and individuals obey the laws, or chaos and anarchy soon result. There is no such thing as competition without the framework of cooperation. Competition is like curry in curried chicken it is not a meal in itself.
CONCLUSION
The differential equations I and II constitute a model. The main purpose of this model is pedagogical. We can use a basketball as a model of the Earth. With such a crude model and a lamp, we can explain the concepts of night and day but not much else. These equations are the simplest model that can be devised to explain the real function of the rubisco enzyme.

Life has a vice-like grip on this planet. It achieved a foothold in what we would consider searing conditions. It has over the last four billion years evolved an unknown number of strategies to improve the conditions for its own benefit. Life is not set to relinquish this planet no matter what our self-serving technology throws at it. We live on a terraformed satellite of the Sun, an engineered system with multiple redundancies built in. We humans, however, fail to appreciate this engineering marvel or the probable consequences of our actions.

Most of the engineering is the handiwork of the microbes. Multicellular organisms are the new arrivals. Animals and plants are, as Lovelock describes, "the icing on the cake". If our disturbance to the atmosphere and climate is to have dire consequences then it will be the icing that slides off the cake. The microbes are resilient. The multicellular flora and fauna will bear the brunt of the changes. The Gaia of the Earth will fall. This fall will gain momentum. Higher atmospheric temperatures will subject temperate and rainforests to so much fire that they deteriorate extensively. The exposed soil will be subject to erosion slowing the re-growth of the forest. The oceans are just as vulnerable and most of the coral is doomed. Warming oceans will dump more CO₂ into the atmosphere making the greenhouse effect more pronounced. Most coral will die. The ice sheets will melt reducing the Earth’s albedo and flooding coastal regions. All tropical and temperate forests will burn. The Gulf Stream, Kuroshio and Humboldt currents may shut down. Methane hydrates will release methane into the atmosphere.
Gaia checkmates Technology: end of contest.

Of immediate concern is the bleaching and death of the coral reefs due to the warming of the oceans. We face the possibility that 400 million years of evolution can be set back for thousands of years by a century of fossil fuel combustion. The damage may last millions of years if the ocean pH falls too far. Realistically, how are we going to remove 200 Gt of carbon from the atmosphere? It is most likely that we will not be able to stop the western Antarctic ice sheet from melting. We may possibly be able to save the eastern sheet but that depends on the oceans continuing to sink CO₂, and on our reducing CO₂ emissions from 8 Gt down to 0.4 Gt.

If we fail to limit CO2 emissions to 0.4 Gt within twenty years then cascading collapses of ecosystems will accelerate. Food production will fall, law and order will evaporate. The gossamer blanket of security that we know as civilisation will become but a distant memory.

Graham Lawson
77 Pine Avenue
Ballina N.S.W.
Australia 2478
Ph. 0437109818
rubgai@yahoo.com.au
Appendix 1
REARRANGING THE EQUATION
ln R - ln (D- A*P*R) = D*t + K3
R/(D-A*P*R) = exp(D*t + K3)
R = D(exp(D*t + K3) –A*P*R*exp(D*t + K3)
R(1 + A*P* exp(D*t + K3))= D exp(D*t + K3)
R = D exp(D*t + K3)/(1+A*P* exp(D*t + K3))
R = D/[ exp(-D*t + K4) + A*P]
Appendix 2

ADAPTING THE MODEL TO THE EARTH AND THE DERIVAION OF EQUATION dR/dt= R*A*δC
In the mathematical model there is no sequestration and there are no emissions from volcanoes. Not withstanding these limitations it is possible to derive this important equation.

At target level dR/dt= 0

0 = R(AC-AoO-Resp)

If C increases by δC then

dR/dt= R(A(C+δC) - AoO - Resp)

Subtracting the first equation from the second gives

dR/dt= R*A*δC

So the power of plant mass to increase is dependent on the product of three quantities: the amount of plant mass; the fertility of the Earth and the imbalance of CO₂ in the atmosphere. The equation is only true for small changes in C. How small is small? The deviation must be small enough so as not to upset the climate as this would affect species distribution and change the value of A. The deviation in C is currently around 0.01 kPa (100 ppm). This is a giant deviation, which will cause all ice to melt and utterly decimate a large number of habitats. I would estimate that in order to maintain the established species, we should not have allowed C to deviate more than 0.003 kPa. We are now in uncharted waters and this equation does not help us a great deal, because the magnitude of A is falling daily, as species disappear or become limited in their range.

Having shown that rubisco is a feedback control mechanism it is time to extend the model beyond its original purpose and apply it to the real world. According to the mathematical model, R increases so that CO₂ levels fall to the target level. The model is not constructed to deal with continuous emissions of CO₂ from volcanoes or the constraint that the Earth has a finite size. But we can easily fix this.

To adapt the model to the real world we can make the following considerations:

• The Earth is almost full of plant matter and any increase in CO₂ will result in more carbon being sequestered and very little change in the amount of living plant protoplasm. It is not necessary to have the plants do all the sequestration themselves, the animals can help out.
• Sequestered carbon is any carbon not held in living cells and therefore has no energy overhead in its maintenance. So the respiration of termites does not constitute respiration in this model when it is applied to the real world. The release of CO₂ by termites is classified as de-sequestration and grouped with emissions from volcanoes.
• There are many modes of sequestration and each has a different half-life. Animal evolution can change the half-life of a particular mode. For example, the evolution of a new species of termite can change the time that a particular species of xylem remains intact. The growth of grass (the formation of non living xylem in the grass) is sequestration with a half-life of a few weeks because herbivores will soon arrive to consume it. The growth of coral is sequestration with a half-life of several thousand years. These half-lives depend on the species that are present and while it is easy to envision these half-lives changing permanently with the evolution of new species, it is also possible to conceive that these half-lives can vary in a cyclical fashion depending on the climate. When the Earth is cold, animal respiration is much reduced and the half-life of many forms of sequestration is increased.
• The emission of CO₂ from volcanoes is de-sequestration because the carbon in the crust was the result of living processes storing carbon.

If increased growth of plants resulted in a permanent increase in the amount of plant protoplasm then it would place a strain on the other mineral cycles and the mineral in shortest supply would soon be the limiting growth factor. Crowding would also be a problem for plants. Extra investment in protoplasm would be rewarded with little benefit to more sunlight. This would defeat the whole logic of rubisco. In the real world, nature somehow keeps the total amount of plant matter at a constant level and as small as possible while collecting as much sunlight as possible. This is achieved in coral and forest by having a thin tissue of living veneer over a skeleton that is a storage of carbon. Obviously if plants grow faster because CO₂ levels rise, more carbon has to be sequestered and respiration increased so that the total quantity of plant matter stays nearly constant. How is this achieved? We know how individual plants and animals sequester carbon but we don’t know how, or if, some overall mechanism exists which keeps the total amount of living plant protoplasm constant. The answer might be simply that light becomes scarce with crowding or the answer might involve the actions of several genes.

We can derive the equivalent equation to dR/dt= R*A*δC using the mathematical model adapted to reality.

Assume the earth was in equilibrium before the industrial revolution. The level of sequestration was equal to the release of carbon by de-sequestering processes.

Seq(per year) = R(AC- AoO - Resp)
If man releases some extra CO₂ then sequestration is increased
Seq +delta Seq = R(A(C+ δC - AoO - Resp)
Subtract the first equation from the second
delta Seq = R*A*δC

And with a touch more panache!
delta Seq = R*A*dC
Appendix 3

ESTIMATING A FOR THE EARTH.
When the Earth is in equilibrium (a difficult concept to define for a system that is continuously evolving and is also programmed to go through cyclical changes) the amount of sequestration is equal to the release of carbon from volcanoes and carbon from de-sequestering activities such as methane released from swamps. If volcanic activity increases and upsets the equilibrium, plant growth will increase. If the Earth is fertile, the extra carbon will quickly be sequestered out of harms way. The Earth is out of equilibrium because of the combustion of fossil fuels since 1830 and forest clearing over the last two thousand years. Measuring the current sequestration rate allows us to measure the value of A.

To measure A we have to measure how much carbon is sequestered each year and substitute this value into delta Seq = R * A(C- .028) where delta Seq is the amount of sequestration that is over and above the amount occurring before the industrial revolution. Currently C is .038 kPa.

To estimate R choose a typical square metre of the Earth and guess how much organic carbon is in living plant cells and then multiply by the surface area of the Earth. My estimate is R = 2 Gt. If the Earth is sequestering 1Gt of carbon above the pre-industrial level then
delta Seq = 2 * A * (.01) the atmosphere being out of equilibrium by .01 kPa
1 = .02 *A
A = 50 inverse kilopascal years

This last calculation is only important from an academic point of view. It is the product of R*A that determines how fast the atmosphere is corrected. We don't really care if R=2 and A=50 or if R=0.5 and A=200 since both mean that the Earth can extract one gigatonne of carbon from the atmosphere per year in its current state of disequilibrium.

OSCILLATING EQUILIBRIUM

At this stage we should have a discussion about the species "mankind". Our species has changed because our interaction with the environment has changed. The equilibrium value of CO₂ depends on the de-sequestering activities of the organisms. When mankind was a hunter-gatherer without the use of fire the equilibrium CO₂ oscillated between, say, 0.17 kPa and 0.22 kPa on about a 130 000 year cycle. After the invention of fire we would expect the numbers would have risen a little. It depends on many factors. How much use of fire did hunter-gather man have in the depth of a glacial cycle?

Another point of consideration is the amount of compliance that is built into the genome of the planet. If a species becomes errant there may be enough genetic diversity in the other organisms to counter the effects of the transgressor. For example, man is raising CO₂ but the algae in the oceans may have switched on genes that increase cloud cover, or methane releasing organisms may slow their metabolism. The Earth is a complicated planet and possibly the most sophisticated part of the whole cosmos.

Guesstimate of A


How do we guess that 1 Gt of carbon is being sequestered every year? The Keeling Curve documents the rise in atmospheric CO₂ and exposes the astonishing fact that as the deciduous forests of the northern hemisphere sprout their leaves in the spring, the CO₂ concentration falls by 7.5 ppm. From the plot it appears that in the ' 60s the spring growth dropped CO₂ by around 7ppm but today the drop seems to be slightly greater at 7.5ppm. It would appear that modern forests are growing faster especially when we consider that there is less forest today than in the ' 60s.

From the curve, terrestrial sequestration (in this context sequestration equates to wood and leaf formation) in the northern summer has risen by 0.5ppm i.e. around 1 Gt of carbon when CO₂ has risen from .0320kPa to .0380kPa. Most of this extra 1 Gt will be respired and not sequestered. If we guess that 10% is sequestered, then 0 .1 Gt of extra carbon is being removed by the northern forests. If the plankton can match this then the oceans are sequestering an extra 0 .5Gt. Ignore the contribution of the southern terrestrial hemisphere.

delta Seq = 2 * A * (.004) from 1960 ; In 1960 the CO₂ level was .004 above equilibrium
delta Seq + .6 = 2 * A *(.01) For 2005 where delta Seq is the rate of sequestration in 1960.
.008 A = .02 A - 0.6 by substituting the first equation into the second
8 A = 20 A - 600
12 A = 600
A = 50 /kPa yr
If we substitute this value back into to 1960 equation then delta Seq = 0.4 Gt. So a reasonable estimate is that delta Seq in 1960 was about 0.4 Gt and today it is around 1.0 Gt. Obviously these guesstimates could be in error by 100%: the Earth may only be sequestering half the amount that I have estimated.
Appendix 4

THE PROSERPINA PRINCIPLE

Greg Retallack has proposed The Proserpina Principle which as far as I understand says that plants cool the Earth and animals raise the temperature. From my perspective we do not need a new theory that is less powerful and less encompassing than Gaia. But the Proserpina Principle does highlight the fact that animals can raise the temperature of the Earth.

One of the problems that hinders our understanding is the absence of any distinct classes, in any area of knowledge except mathematics. In mathematics within the set of integers there are even numbers, odd numbers and zero. There is no overlap between these three subsets. In science and other studies there are no distinct sets. So while we talk as if there is the set of plants and the set of animals and nothing in between, we are ignoring the fact that the distinction between these two groups is somewhat arbitrary. There is a host of micro-organisms that we cannot decide if they are plant or animal. It would not matter if we became infinitely more fastidious with our definitions there are always organisms that are difficult to classify. So the Proserpina Principle creates problems for itself right from the beginning because at its heart is a murky distinction between two groups.
Retallacks's idea that animals raise the temperature of the Earth posed a problem for me. Is it possible, and if it is true, how does it fit in with the mathematical equations? Firstly, Retallack just mentions animals while the mathematics requires two classes of animal. According to the mathematics which is all done as computer representations of differential equations, there are animals that eat protoplasm and there are animals that bring sequestered carbon out of storage. Of this latter type, should we distinguish between termites that consume carbon that was stored fifty years ago, and bacteria that eat plagioclase, a mineral made from carbon that was stored four hundred million years ago? Then there is the problem that most herbivores actually consume both protoplasm and cellulose – the carbon in protoplasm is part of the variable “R” and the carbon in the cellulose is part of sequestered carbon.
In a stable planet, protoplasm consuming organisms are always at their maximum numbers either limited by food supply or predators. We could be talking about elephants or aphids. Let us consider elephants. The only way we can have greater CO₂ output is to have more elephants but the elephant population if it was limited by food supply can not increase without some major shift in the ecosystem. If the elephants changed in some way by doing something new they could change the landscape. If they push over a forest so that the forest is replaced with grassland then the temperature of the atmosphere would rise for a short time. As a general rule the forest had a lot more carbon in storage than the new grassland has, so the CO₂ level would rise. Assuming that the nitrogen cycle and other mineral cycles are in good shape, all plants will start growing faster as rubisco is now more efficient and more sequestration will take place. Depending on where the CO₂ is sequestered the Earth could end up being hotter or colder.
Now we can consider a mutant variety of termite. If the new termite can decompose wood at double the rate of the old termite, more CO₂ is released but the termite quickly runs out of a food supply and no permanent change results. But one possibility remains and this is how the Earth actually improves – this is how the value of A changes from 50.00 to 50.01 making the Earth a more fertile place and more capable of adjusting the atmosphere. It requires the termite to do two things. In addition to bringing carbon out of storage it must also help with one of the other mineral cycles or help with some other aspect of the Earth's fertility. Suppose the termite also assists in improving the habitat of a nitrogen fixing bacteria. If the termite and the bacteria allow larger trees to move into new habitat, habitat that was previously occupied by slower growing species then the value of A will have been increased but the Earth will not necessarily be hotter. If the forest stores more carbon than the scrub did, the Earth should be colder. I say should, because every organism interacts with many others and the cumulative effects of all these changes are too difficult to predict.
Let us imagine that man evolved and progressed up to about 1700 AD and then became steady in population and technology. He should have made the Earth hotter as a result of forest clearing and the combustion of small amounts of coal. As long as the large forests of the world had not run into a shortage of nitrogen we can envision a warmer balanced Earth that could continue indefinitely. The unseen difference being that the Earth is revving closer to the red line. That is, the Earth would have less spare capacity to deal with a large volcanic eruption.
However it is possible that man could have lowered the temperature of the Earth. If early agriculture had involved the growing of nut trees or any large food-bearing tree as opposed to the production of cereal crops, then we can imagine the Earth becoming slightly colder.
So I would have to disagree with the Proserpina Principle. In my view any organism has the power to heat or cool the Earth. If carbon moves into long-term storage the Earth cools. If carbon moves into short-term storage the Earth warms.
Appendix 5

MOVING FROM 'A' AS A MICROSCOPIC VARIABLE TO 'A' AS A MACROSCOPIC VARIABLE.
The equation dR/dt = R(A*C-Ao*O-Resp) originally did not contain the term for respiration. In the computer model the respiration term appeared in the second differential equation. This term was moved into the first equation when solving the equations mathematically as a means to see if a solution was correct. Both arrangements gave the same result, so Resp was left to remain in the first equation. This does not mean that I knew exactly what I was doing. I first considered the respiration term, as animal respiration and I thought of it as a certain fraction of total respiration. This interpretation is wrong. The respiration term returns all CO₂ to the atmosphere (when equilibrium is reached) that is not accounted for by photo-respiration So of all the CO₂ returning to the atmosphere, about 1/4 is produced by photo-respiration and 3/4 is produced by the respiration term.

While A and Ao have microscopic interpretations, Resp does not.

On a macroscopic scale, A is a family of three numbers. If the Earth is fertile all three are big numbers, the curves are steep and equilibrium is achieved quickly. Conversely, if the Earth is compromised because many species have become extinct, then all three numbers are smaller and the Earth will take longer to adjust CO₂.

On a microscopic scale we are interested in the relative size of A*C and Ao*O, because it is this relativity, which sets the efficiency of photosynthesis and thereby directs the atmosphere towards the equilibrium value of CO₂. So if we look at A by itself, in a laboratory we are working on a microscopic scale, we are determining the ratio A*C to Ao*O for a particular species of rubisco molecule. When we calculate A for the Earth (we have also calculated the value of Ao as a by-product), we are looking at the macroscopic scale. The value of Resp has a little independence from A and Ao. It can change by itself to some extent because the CO₂ level can change.

Imagine a stable fertile planet. All three numbers are large. If a new herbivore evolves, say a beetle that begins to munch on a prolific water weed, then respiration increases (Resp increases to a new bigger value) and CO₂ levels will rise. As long as the environment is not harmed then the Value of A remains as it was. The value of Ao has to remain linked to A. The concentration of CO₂ will increase so that at the new equilibrium
AC - AoO - Resp = 0

So the new beetle has increased CO₂. Photosynthesis has increased by making rubisco work more efficiently. You might think that the animals have control of photosynthesis and you would be correct to some degree. As animals increase, CO₂ levels increase, and plants grow faster because they waste less energy in photo-respiration If the animals somehow improve the nitrogen cycle and perhaps some other cycles as well then a positive feedback loop develops. This means that the value of A and Ao will begin to enlarge and the plants can grow faster still. Of course things will soon settle down as there is a limit to how much the animals can increase the mineral cycles. If the animals decrease the fertility (A) or if they reduce the plant mass (R) then photosynthesis decreases and the food supply dwindles. Respiration levels fall because the beetles begin to starve.

The world grain harvest has increased dramatically in the last few decades as a result of high yielding varieties, nitrogenous fertiliser, warmer weather and higher levels of CO₂. This trend will soon reverse, as soil erodes, the weather becomes too hot and storms increase in severity and frequency.
You might think that man has increased the Gaia of the planet by making some crops grow faster. This is not necessarily the case because the Gaia of the Earth depends on which crops are growing and what happens to the carbon in these crops. The Gaia measures how fast the CO₂ level can be adjusted so if we use our fertiliser to grow faster growing forests, then we have indeed increased the Gaia of the Earth. However if we replace forest with cereal crops with the nett result that there is less opportunity for sequestration then we have reduced the Gaia.
Example of a planet correcting its atmosphere

Supposing a living planet has stable CO₂ at 0.00002 kPa and volcanic eruptions raise this level to .00003 kPa. Faster plant growth reduces the level to .000025 kPa in 1000 years. Given enough time the levels would eventually get back 0.00002 kPa. Can we calculate A, Ao and Resp?
In order to calculate this group of numbers we would need to know the pressure of oxygen in kPa, the total carbon mass in living protoplasm and the ratio of time that the rubisco molecule spends reacting with carbon dioxide and oxygen. However without these three measurements we can still satisfy our mathematical curiosity.

Let us assume that this imaginary planet like our Earth, is quite full of plants and there is no room left for any more and that the increased growth will become sequestered carbon in the form of xylem, organic material in soil or ooze on the bottom of the ocean. This means that R will not actually change in size.

So we can't write dR/dt= RAδC because we are not letting R increase in size. But the plants are growing faster and removing carbon from the atmosphere so we can write -dC/dt= PRAδC
Where P is the constant of proportionality, which converts gigatonnes of carbon to partial pressure. i.e. C = P*Carbon content of the atmosphere: having units of kilopascal per gigatonne (kPa/Gt)
C is the partial pressure of carbon dioxide
R is the mass of carbon in living cells
δC is the imbalance in the level of C, (in this example the initial imbalance is .00003 -.00002 = .00001 kPa)
-dC/dt= PRA(C-.00002)
dC/dt=.00002 PRA - PRAC
The solution is given by
C=(1/PRA) *[.00002 PRA - K (exp -PRAt)] and K is a constant of integration that can be determined by the initial conditions
When t=0 C=.00003
C=(1/PRA)(.00002 PRA - K)
.00003 =(1/PRA)(.00002 PRA - K)
K=- .00001 PRA
When t = 1000 years C=.000025
PRA(.000025) = .00002 PRA + .00001 PRA (exp - PRA* 1000)
25= 20 +10 (exp -PRA*1000)
5= 10 (exp -pra*1000)
-PRA*1000= ln(.5)
PRA= .69/1000 = .00069
If we could measure P and R then we would know the value of A. For the Earth R is approx 2 Gt and P is around 0.00005 kPa/ Gt

Using R= 2 and P = 0.00005

A= 6.9 inverse kilopascal years

These calculations assume that during this one thousand years the species distribution did not change.

Appendix 6

ONE PROBLEM AFTER ANOTHER

Most people appear to be aware of the threat of climate change. However they have not made the paradigm shift to viewing nature as the supreme technology. The old mentality still exists. They see CO₂ as the problem and the obvious solution is to bury it. They do not perceive that CO₂ is just the first of a whole armada of problems about to beset us. When the oceans are empty and the soil is gone, feeding the human population is going to be difficult. The animal and other kingdoms run the mineral cycles. Without these organisms the mineral cycles stop. Without the minerals the plants do not grow. Each, can not return because the other is missing. A global catch 22 situation develops. Reducing the diversity puts evolution into reverse. The Earth will become less fertile and less robust.

Biodiversity is not going to be replaced by gene technology. The Earth is a massively parallel evolving computer. Every cell of every individual has the complexity of a supercomputer. The program of this computer has been running and evolving for 4.5 billion years and while it does not have the conscious thought and planning of the human mind it has produced a genome that controls the planet within the laws of physics and chemistry. As a complex system the Earth is subject to chaotic behaviour, a few flaps of a butterfly's wings can totally change the future of the system.

Eventually the Sun will swallow the Earth. For the remaining time that we have, it would be disappointing for the human race to degrade the genome and commit future generations to existence on an impoverished planet, when the alternative has much more to offer: retain the enormous infrastructure of genetic diversity and allow all species to play their part.
Appendix 7

KEEPING R CONSTANT

To keep R constant it is possible only four (perhaps less) conditions are necessary

• high rates of reproduction - lots of seed or spores
• a rubiso enzyme
• a base-load respiration rate
• reduced access to sunlight from shading by other plants

These conditions should ensure that plants rapidly cover the available habitats and keep younger plants stalled for lack of sunlight.

Gaia Hypothesis Evidence page two (of three)

previous page

ASSUMPTIONS


What about sunlight? What about the oceans? What if respiration is not constant but is temperature dependent?

Clearly there are limits to the rate of growth of plant matter. If plants are already using all the available light or all the available nitrates then the rate of growth cannot be increased further. This places a limit to the quantity of plant matter that can exist on the Earth. These equations assume that plants are not at the stage where their growth is limited by the supply of some mineral. It is assumed that a plant's growth is only limited by its size (big plants grow faster) and the availability of sunlight.

In addition:
Sunlight is already incorporated inside the affinity factor. Sunlight, mineral supply and the activities of every living species, determine the value of A for the Earth. If there were more sunlight and minerals then A would be a bigger number than it is. Similarly if we build a road where plants cannot grow then we have reduced the size of A.

You are probably, at this stage, having difficulty understanding how 'A' can simultaneously represent two different physical phenomena. How can it represent the affinity of an enzyme for a molecule and also the Gaia of the Earth? Fortunately physics has provided us with an analogy. The kinetic energy of a molecule of a gas (microscopic variable) describes how fast the individual molecule is moving. Yet the average of all the kinetic energies generates a property called temperature (macroscopic variable). So a number that applies to one molecule when averaged over a group creates a quantity that describes a property of the group.

A ballpark figure for A is around 50/kPa years. (New units especially inverse units are always a pain to mentally assimilate but here you just have to remember these figures: 50 /kPa years means the Earth can sequester 1 Gt of carbon each year and 25 /kPa years means the Earth can sequester 0.5 Gt of carbon each year. This is true while the atmosphere is out of equilibrium by .01 kPa. If the atmosphere were to be allowed to correct itself, the amount of sequestration will diminish as equilibrium is approached.) This is a measure of the fertility of the Earth. It determines how fast the plants can grow and sequester to achieve an equilibrium level of CO₂. This value is dictated by: solar output, ozone levels, the temperature of the atmosphere, the availability of minerals in the soil, the currents in the ocean, the diversity of the plants and animals: anything that affects the plants' ability to grow and spread (even spreading in to new habitats - so the rate of mutation is a part of the fertility of the planet).

An analogous concept is horsepower. The horsepower of a vehicle, as measured by the rate at which it can climb a hill, is determined by many factors, these being: the cubic capacity of the piston displacement; the size and timing of the valves; the efficiency and timing of the spark plugs; the friction of the oil; the aerodynamic shape of the body; the inflation pressure of the tyres and many other criteria. Any one of a thousand different factors will affect the effective power of a motorcar. Similarly, any one of a several billion factors will affect the fertility of the Earth.

OCEANS

Imagine an Earth without oceans. As long as the land receives rain, then the plants grow and the mathematics works. Alternatively, imagine an Earth without land. The mathematics might have to be adjusted slightly for the exchange of gases between the atmosphere and the ocean but basically the model would be the same.
TEMPERATURE
 
The plot above shows two curves produced by a computer program. The lower, allows for respiration to be temperature dependent and the higher plot is produced when respiration is independent of temperature. If the purpose of the model is simply to demonstrate that rubisco is a regulator then we can assume that respiration is independent of temperature. If at some stage we wish to extend the model then we may desire to make some allowance for temperature dependent respiration.

THE MATHEMATICS OF HOW RUBISCO WORKS TO RETURN THE ATMOSPHERE TO THE EQUILIBRIUM LEVEL


If the species distributions are static then rubisco will work to maintain the equilibrium level. The equilibrium level is set by the rate of sequestration and the rate of release of CO₂ by volcanoes and the actions of decomposers such as termites and fungi. If volcanoes increase in activity, CO₂ levels will rise, and rubisco will become more efficient. More energy will be fixed into carbohydrate and more carbon will be sequestered. The CO₂ level will begin to fall as long as the mineral cycles can keep up with the demands of the plants. Rubisco does not determine the equilibrium level, it just helps ecosystems return CO₂, to the equilibrium level.

To reduce confusion the term "target level" will be used to refer to the CO₂ level that rubisco is aiming for. If we are talking about an Earth with a particular set of plants and animals then the terms "target level" and "equilibrium" become interchangeable. The mathematics below only applies to the model.

This particular model is accurate if plant mass is increasing but not directly applicable if plant mass is not increasing. Essentially we are looking at the mathematics of those spinning balls (the governor) on a steam locomotive which ensures constant rate of motion no matter what the slope of the track.
If we let t approach infinity in equation 5 then

R= D/(A*P) is the stable carbon mass of all plants when the target level of CO₂ has been reached. It is important to notice that this value depends on the initial conditions. If at time zero there is a lot of CO₂ in the atmosphere then the stable level of R will be greater than if the atmosphere initially contained less CO₂. This is not the situation that exists in the real world. In the real world, plants and animals have evolved a means of sequestering carbon in non-living material, e.g. xylem or calcareous shells. This improves conditions immeasurably and this fact is not taken into account in the two differential equations. Without this assumption the equations need a term for sequestration, become much less flexible and more difficult to solve.

The original purpose of the mathematical attack was to give some support to the computer simulation. However the mathematical exploration once begun, yielded an insight that was totally unexpected – the fertility of the Earth.

If we let t approach infinity in equation 6 then we have an expression for the stable partial pressure of CO₂.
C= P*K2 - D/A This is only true at target level

Now D = A*P*K2 - AoO - Resp
C _{target level} = (Resp + Ao * O)/A equation 7

We can see that the target level of CO₂ in the atmosphere is determined by:
The magnitude of the respiration variable (the animal community has a moderate say in this)
The partial pressure of oxygen
The ratio of the affinities of the rubisco enzyme for oxygen and carbon dioxide
(These three factors which determine the target level had me bamboozled. In the computer models my brain was happy to accept that the amount of carbon in the atmosphere was controlled by net sequestering activities of plants and animals. Yet the mathematical model dictated that the equilibrium level was determined by the three factors above. My brain accepted both as truth even though both can not be true. The resolution to the problem arises when we realise that in the real world the amount of plant matter 'R' does not change, it always stays at around 2Gt.)
MODELS


All theories are models because all theories are simplifications of reality. These simplifications allow us to see the wood from the trees. Supercomputer models of climate are very complex and valuable tools. Improvements are made on a daily basis but any climatic prediction more than five years into the future can be taken with a grain of salt. The truth is that we do not yet, know enough about how ocean current circulation will change. With warmer oceans, how will the flux of CO₂ change? Dimethyl sulphide is the principal sulphate aerosol, its release by coccolithophores seems to be at the mercy of viruses and grazing micro plankton. How can we program this into our supercomputers when we don’t really understand what is going on? This does not mean that supercomputer models of climate are a waste of time, it just means that a lot more sophistication is required. The success of any model depends on the truth of the data that we program into the model. While we can be confident about our understanding of physics and chemistry, the physics and chemistry is at the mercy of the biota. The surface area of the atmospheric-water interface in living systems is estimated to be 200 times that of the ocean-atmospheric interface. So if we are calculating the rate at which co2 dissolves into the ocean then we must also allow for the gas rapidly moving into and out of terrestrial organisms and the movement of groundwater into the ocean. In a prediction of future climate we would need to know which species are going to survive and their exact roles in all mineral cycles - information we are never likely to possess.
THE MEANING OF A


Although I have already explained the concept of A as representing the Gaia of the planet, you might not be convinced. There has to be some mathematical basis for this concept. The Gaia of the Earth is a number that describes how fast the plants and other life forms can get the carbon dioxide levels back to equilibrium whenever some disturbance upsets the carbon dioxide levels. Think of this analogy: R is the number of workers and A is their average level of skill. To work out how long a project might take to be completed we multiply R and A to determine the level of productivity. In this model R is the total carbon-mass of plants (excluding cellulose) and A, indirectly, represents a number describing how fast these plants can grow.

Let us apply the model to the whole biosphere. To do this we only have to make one assumption.

• Assume that the Earth is nearly full of plants. When extra growth occurs because of a rise in CO₂ some new growth will go into sequestered carbon and some into protoplasm. Animals will quickly consume the protoplasm because animals have such prodigious powers of reproduction. These animals will themselves be consumed by something further up the food chain. The result will be that more carbon is sequestered. Eventually all the extra carbon will be sequestered. If this assumption is wrong, resulting in a permanent extra level of plant protoplasm, a greater increase the use of minerals arises, necessitating faster supply of iodine, copper, cobalt and other elements. Coordinating all the mineral cycles just to deal with a bit of extra CO₂ is somewhat of a big ask when keeping plant protoplasm as a constant level is a much easier option.

Consider the expression dR/dt=R*A*δC from (link not active at present)mainthree.html#appendix2
dR/dt is the rate of growth of plants. Delta C( δC ) is .01 kPa. It is the imbalance in the CO₂ level. The current CO₂ level is 0.0380 kPa. The equilibrium should be 0.028 kPa as determined by the set of organisms that currently inhabit the Earth. This was the gas level in 1830 AD prior to the industrial revolution. (This argument assumes that Man is the same species today as he was in 1830. Genetically he is the same but from and ecological perspective he is a different species because his interaction with other species has changed so dramatically.)

If we assume that the Earth is long-term sequestering 1 Gt of carbon each year then we can set dR/dt= 1.0
We set the sequestered carbon to what R, should change by, even though R does not change. In the real world R does not change, probably because the Earth is full of plants. The equation does not consider sequestered carbon, so to work around the problem we set sequestered carbon to the change that would have occurred in R.

1.0= R*A (.01) The Earth is working 100 ppm (.01 kPa) outside of the equilibrium value and until the mass coral bleaching began, it seemed to be coping (ignoring other activities such as deforestation)

R*A = 100 Gt/ kPa yr

Now we must ask ourselves where does the value of 100 come from? The answer is obviously the fact that the Earth can, in its present condition, extract an extra 100 Gt of CO₂ per year from the atmosphere when CO₂ rises by 1 kPa, or in keeping with realistic movements of CO₂, extract an extra 0.1 Gt of CO₂ for a rise of .001 kPa (approximately 10 ppm). So we have R*A = the potential to increase the rate of extraction of carbon dioxide as carbon dioxide levels rise.

Let us consider the factors that might affect this "potential for increased extraction". We might consider the following: What if the Earth had no bees? Then the rate of pollination and the number of seeds that set would be reduced. After a large forest fire, CO₂ levels would rise above equilibrium. The speed at which growth can proceed depends on the fertility of the soil and the rainfall. Growth in the burnt regions cannot proceed until the seeds are spread into these areas. Without bees, the trees will set less seed. The process of colonisation will be slower and the return of the atmosphere to equilibrium will take longer.

Now R can be calculated by measuring the total dry mass of plant matter (excluding cellulose). So we can place a new (global as opposed to microscopic) interpretation on the numerical value of A. We can take it as a measure of the quality of the Earth or the power of living things to balance the atmosphere. This is the same as a measure of how much plants can increase their growth rate in response to an increase in CO₂. But not all of this increased growth will be due to the rubisco enzyme working more efficiently. The extra growth that takes place will depend on the supply of rain and minerals. If the plants run out of nitrogen then extra growth is not possible - so the efficiency of the nitrogen cycle is important. The Gaia of the Earth (A) and the total carbon-mass of plants (R) combine to determine how fast carbon dioxide can be adjusted.

The sequestering ability of a whole ecosystem is a product of the myriad of interactions of the species. If we knock down a forest then within a few years most of chlorophyll has returned. The chlorophyll may not be in the leaves of trees, it may be in weeds or grass. The problem is that the fertility of the ecosystem may only be a fraction of what it was. The new plants (pioneer species) will not be able to grow very fast if the topsoil has washed away. These new plants being small will not have the carbon sequestering ability of a fully functional forest.

Every time we build a city and exclude plants from places where they can catch sunlight, we reduce the value of A and R. If we only chopped the plants down and did not build the city we would only be affecting R and not A. When we pour the concrete, then we are reducing future potential for growth, so we are reducing A as well.

To push the car analogy a bit further: the horsepower of the engine depends on the number of cylinders and the efficiency of the combustion process. If someone disconnects a spark plug lead, then the horsepower is reduced. No permanent damage to the engine results and the damage can easily be repaired. This is analogous to cutting down some trees or mowing the lawn. If however the engine is seriously damaged by wear on the rings then the engine is less efficient until it is totally rebuilt. This is analogous to pouring concrete to build a city or causing the extinction of a species of bird or allowing top soil to be washed away. The damage lasts until the city is removed, or a new species evolves to perform the job that the bird previously did, or leaf litter regenerates the soil.

Every time we reduce the population of a species that helps a plant to grow we reduce the value of A. For example, supposing ants became less numerous, then the porosity of the soil would be reduced and less water would penetrate into the soil. The rate of growth of plants would be slowed. "A" is calculated from the rate at which plants extract carbon from the atmosphere. If any species becomes extinct and that species helps a plant to grow and sequester carbon, then the value of A will be reduced.
THE DEFINITION AND CONSTANCY OF R plus more
The definition of this variable is somewhat arbitrary. It is designed to be a measure of the carbon-mass of plant matter. In the mathematical model the definition is easy – if CO₂ enters the plant and stays inside then R has increased in size. When the model is adapted to the real world some difficult decisions have to be made. We have to distinguish between sequestration and growth and unfortunately there is no clear method to make this distinction. The problem arises because there is no hard definition of sequestration. When a plant uses carbon to make a compound then the carbon may stay out of the atmosphere for twenty minutes or one hundred thousand years depending on happenstance. So we need to make an arbitrary decision whether formation of cellulose is a form of sequestration or growth. I argue that since cellulose is not recycled quickly and has no maintenance demands for energy it belongs in the sequestration category.

The value of R, rose to some maximum value, very early in the Earth’s history as the first cyanobacteria conquered all the available habitat. Subsequently, the amount of plant matter rose much more slowly as evolution of new species was needed to invade new types of habitat or convert non habitat into suitable space. One could speculate that most of the Earth was conquered by some sort of plant within 500 million years of the origin of the first cyanobacteria. The value of R today (guesstimated to be around 2 Gt) is more or less constant.
The Earth has been full of plants for around three billion years. For much of this time the plants were much more primitive than modern terrestrial species that inhabit the globe today. Over time the living things have become more diverse, more complicated, and more sophisticated. We can actually devise a means of measuring this sophistication. Whereas the Gaia is a number that measures how fast CO₂ can be adjusted, Sophistication is measured by how fast the planet can adjust the Earth's radiance. The mean radiance of the Earth is currently around 230 watts per square metre. The living things can adjust this number by changing cloud cover, greenhouse gas content of the atmosphere or species make-up of forests and grasslands. So the Gaia is just one component of the Sophistication of the Earth.
(missing graphic -nasa image of the earth in the infra-red spectrum. Having difficulty uploading image)




Quiz Time:If the ability of the Earth to change the albedo and infra-red emissivity was measured via changes to the radiance, what would be the metric units of Sophistication?

THE MOST IMPORTANT EQUATION IN OUR PART OF THE UNIVERSE

It is time E = mc² was demoted from first place in the mind of popular imagination. Here is an equation that may stop man's insane attitude to growth.

delta Seq = R*A*δC (equation 16)
Where
delta Seq is the rate at which the atmosphere is corrected. It is directly proportional to the rate of photosynthesis of plants

A is the Gaia of the Earth. (a number representing how fertile the Earth is per gigatonne of plant carbon)
R is the carbon mass of all living plant cells. (it does not include sequestered carbon such as cellulose in xylem)
δC is the imbalance in the Earth's atmospheric carbon dioxide determined by our assumption that the atmosphere was in balance in 1830 and that the same set of species is alive today. It does not matter that some species have become extinct, I’m just trying to explain what the mathematics means.

This equation is not startling at first glance. It simply says that the rate of correction of the atmosphere depends on three factors: the total living plant mass, the fertility of the Earth and the imbalance in carbon dioxide partial pressure. This equation is only true for small deviations from the equilibrium value of CO₂. Rubisco can only increase growth when there are no other factors limiting growth such as the supply of minerals. Equation 16 is just as valid in a greenhouse growing tomatoes – to grow a lot of tomatoes it is necessary to have: a large number of plants, a high CO₂ level, and all the conditions for high fertility such as fertiliser, temperature and light.

What is important is the meaning we give to this simple little equation. The fossil fuel industry will simply say "… you are telling us that carbon dioxide is food for plants; we knew that." What needs to be explained to the fossil fuel industry and everyone else, is that the Gaia of the planet can rapidly change. The death of large areas of Indian Ocean corals in 1998 is the portent of our future. The next big El Nino will probably wipe out most of the Pacific corals. This may knock the Gaia down by a large amount but my computer model predicts a scenario where dying coral actually give us a bit of breathing space in the short term but comes back to bite us in the long term. If the Atlantic conveyor shuts down and Europe freezes over, then the Gaia will drop some more. If this sort of scenario becomes reality, then humanity will be well primed to understand the concept of "Gaia of the Earth". The tomato greenhouse offers a graphic analogy – if the humans are taken out of the greenhouse then all the work is left undone. How many tomatoes are going to grow if the fertilising, weeding, spraying and planting are not carried out – all these tasks have to be done or the environment becomes infertile. As the animal life becomes extinct on this planet there are a lot of tasks that are not going to be completed.

To illustrate this point a little further. Japanese fisherman are having enormous trouble with the numbers of jelly fish that are filling their nets. Biologists see the obvious cause of the problem: too few predators of the jelly fish larvae. If you remove the sardines from the oceans don't complain when jellyfish populations explode.

According to Santo Bains of Oxford University (Nature volume 407 page 171) global temperatures soared around 55 million years ago when volcanoes pumped huge volumes of CO₂ into the atmosphere. Bains concludes from barium sulphate in ocean sediments that very strong planktonic growth followed for 60 000 years and brought levels back down. However this data does not throw much light our current predicament because we need more information. How hot did the atmosphere become? How much CO₂ was released and at what rate? To what extent were the ecosystems disturbed?

As with all laws, equation 16 is an approximation to reality. This does not reduce its importance. Maxwell's equations are not valid for atomic scales and have to be replaced by quantum mechanics to explain the behaviour of electrons in atoms. Newton's laws take no account of relativity. Equation 16 demonstrates to us that the Gaia of the Earth is measurable and it is a construct of all living processes. If minerals are recycled quickly, if plants can live in all habitats and if plants and animals can sequester carbon, then life can manipulate the atmosphere to maintain a habitable planet. When A for the whole Earth is large ~ 50/kPa yr then the atmosphere can be manipulated rapidly, when A is smaller ~ 20/kPa yr then the atmosphere is manipulated more slowly.
DEFINITION OF LIFE AND THE NEW FOURTH LAW OF THERMODYNAMICS


Many scientists consider that we do not yet have a satisfactory definition of what life is. Perhaps we have been overlooking something, something that should have been obvious. The Gaia Hypothesis states that life controls the planet. Taking the inverse of this statement we arrive at: Control of the environment is a feature of living things. This is the original assumption Lovelock made when working at the Jet Propulsion Laboratory - the idea, however, in his subconscious was probably less forthright and more along the lines "living things betray their presence by changes to the environment."

Consider this list of characteristics of living things taken from my school textbook, Science for High School Students copyright 1963, containing 1040 pages and weighing 2 Kg.

Movement
Responsiveness
Assimilation
Growth and development
Reproduction

The eminently qualified people who wrote this tome would have been well aware that: plants produce oxygen; plants shade the soil and produce leaf litter; animals defecate; worms move millions of tonnes of soil; bacteria assist in the weathering of rocks and bacteria drive the nitrogen cycle – to name but a few of the many ways living things affect the environment. But not one of the authors saw fit to consider, that changing the environment, is an important property of living things. Why? Over fifty of Australia’s leading scientists and science educators of the 1960’s could not see this obvious piece of induction.


The Second Law of Thermodynamics permits the possibility of life on Earth because the increasing order on the Earth is paid for by the increasing disorder of the sun. We need a fourth law to help us understand how life arises. Just how this law could be formulated mathematically requires some imaginative thought. (See fourth law link not available yet)


This new law needs to explain the logic of evolution and Gaian theory. Those who understand evolution find the development of adaptations and increasing diversity perfectly logical in terms of natural selection. Lovelock has been attempting to persuade the scientific community for thirty years that living things evolve cooperatively. As previously stated, the mental hurdle that we have to overcome, is: how can a new adaptation, that does not immediately benefit the individual, help it to survive? Early last century Erwin Schrodinger showed that electrons could tunnel through a potential barrier. His mathematics predicted something that had never been observed. Today we have the science in the reverse order (the normal order in which science is done): we observe (in this special case we 'infer') life doing something strange (life beginning from the inanimate) and we need the mathematics to explain how it can be done.

Translated into words the new Fourth Law of Thermodynamics says, "If life can evolve then it is most likely that it will evolve. This will happen because life is that system which is able to adjust its own chemical conditions and therefore able to propel its own development." With this law we can argue more convincingly against the hypothesis that life began in outer space. I have no deep-seated objection to life beginning in space but I’m suggesting that it is more probable for life to begin on Earth. Life must modify its environment as it progresses (to optimise its physical conditions e.g. temperature). It seems more likely to me that the first chemical interactions could modify the local physical conditions on Earth (be they underground or in a lake) more easily than modifying the conditions on some asteroid or gas cloud in space. If ninety percent of evolution, can occur on Earth as documented by the fossil record, then it seems likely to me that the first ten per cent of evolution also occurred on Earth.

GREENHOUSE DEBATE


How much evidence is needed to convince governments that it is time to take radical action to curb greenhouse gas emissions? Economists are keen to use forests (so called carbon sinks) so they can maintain coal dependent economies and standard of living. In fifty years when a forest has absorbed most of the carbon that it can, it ceases to be a carbon sink. Then what do we do? (In the words of Pieter Tans "it's difficult to conceive", his response to the suggestion that the biosphere could absorb greenhouse emissions). What if the forest burns down? Does the individual or company that sold the carbon credits pay back the money? More interestingly, to whom are the credits repaid? Carbon trading is a nonsense because there are no long term fail-safe carbon sinks that are available to mankind. Sequestration of carbon dioxide from coal burning power stations by pumping the gas into underground storages is never going to be competitive with wind and solar energy.

Polar ice cores indicate that the levels of greenhouse gases in the Earth's atmosphere have closely paralleled the changing climate over at least the last 250,000 yr. (Barnola et al.) The graph from Vostok ice cores is totally convincing. Keep in mind that knowing the cause of climate does not mean that we can predict all aspects of climate, such as ocean currents. (missing graphic shows temperature of the atmosphere and CO2 level for the past 300 000 years)


Diagram from http://www.noaa.gov/
Other ice cores have extended the data back to a period of 600 000 years.

Some of the other aspects of climate need to be elucidated. We still have to understand the mechanisms involved in cloud formation and ocean current/plankton dynamics. Understanding climate, as difficult as it has been, is only the beginning. The greater and more difficult task that lies ahead is understanding how all the species interact to manipulate the production or management of: dimethyl sulphide, growth on coral reefs and other feedback mechanisms of which we are totally unaware.

Much of the data is coherent but some mysteries remain. Why were the Ordovician and the Jurassic cool when the proxies for CO₂ suggest this gas was high in concentration? Are the proxies to be believed or were other factors responsible? Our understanding of the Jurassic (205 – 135 mya) atmosphere is less evidenced based than the extensive work of Barnola that ties CO₂ to climate.

The decision to avoid fossil fuel will not be made as a result cogent argument from the scientific community because the fossil fuel lobby is too powerful and our technological society is predicated on cheap energy. The scientific community has done all that it can. The decision will be a result of the weather and rising sea levels. Changing climate will disrupt food production and water supplies. Rising sea levels will drown all low lying coastal cities. We can only hope that when the real commitment to avoid carbon as a source of energy takes hold of public consciousness, that starvation has not pushed the world into armed conflict.

The northern summer of 2002 witnessed the worst forest fires in the history of North America. Hurricanes Katrina and Rita are harbingers of warmer oceans. When similar or even more severe storms return in the near future, the lesson will be learned. However the transition to alternative energy will take at least ten years and the recovery of the atmosphere will take between 300 to 5000 years depending on the actions of mankind.

If the Earth can sequester 1 Gt of carbon per year (nobody knows exactly what the figure is) and if all fossil fuels were banned, then most (80%) of the excess CO₂ would be extracted in around 300 years. The process is asymptotic and it would take quite some time to make it all the way back to 280ppm. Realistically we do need to maintain an airline industry and carbon based fuels will be convenient is some small special niches. If we allow the airlines 0.3 Gt of carbon emissions then it could take several thousand years to restore the atmosphere. But this means the melting of all ice and a sea level rise of 80 metres.

The Greenland sheet is melting at an astonishing rate, it contains enough ice to raise sea level by eight metres. The western Antarctic ice sheet could, and probably will, break up within 100 or 200 years raising sea level by another eight metres. This estimate (100 - 200 years) is based on the only information that is available. Fourteen thousand years ago the western shelf was much larger. It broke down to its present size over a 500-year period, in response to a rise in CO₂ levels of 50 ppm. The sea rose 130 metres. Since the industrial revolution CO₂ has risen another 100 ppm. Will increases in snowfall at the poles compensate for increased rates of melting and ice calving at the edges? No. Over the past few years the GRACE satellites are measuring 132 (Western Sheet) 57 (Eastern Sheet) and 195 (Greenland), for a total of 384 cubic kilometres of ice melting each year (Nature Geoscience November 2009). But even these figures appear to be out of date. The graphs below show the melting rate from 2007 to 2009 has been close to 500 cubic kilometres per year. The IPCC is predicting half a metre of sea level by the end of the century. However this prediction is far too conservative according to the CSIRO and does not consider the possibility that large parts of the western ice sheet can break up rapidly. The Pine Island and Thwaites glaciers could rapidly collapse and melt.


Figure 1 shows the ice mass changes in Greenland for the period April 2002 to February 2009. The blue line/crosses show the unfiltered, monthly values. The red crosses have seasonal variability removed. The green line is the best fitting quadratic trend.




Figure 2.
Figure 2: Time series of ice mass changes for the Antarctic ice sheet estimated from GRACE monthly mass solutions for the period from April 2002 to February 2009. Unfiltered data are blue crosses. Data filtered for the seasonal dependence using a 13-month window are shown as red crosses. The best-fitting quadratic trend is shown (green line). From Velcognia 2009.


Long-term climate predictions are fraught with uncertainties. The Gulf Stream delivers enormous quantities of heat to Europe. Ice core and other studies in Greenland suggest that the Gulf Stream has in the past, shut down. This brings colder conditions to Europe and ultimately affects the Earth’s albedo. So it is possible that Europe could get colder while the tropics become unpleasantly hot. In this scenario with the ocean conveyor shut down, the ocean produces much less food because the up-welling of cold bottom water stops. In this condition it is possible that the oceans become anoxic cesspools. The oceans currently produce around 90 million tonnes of fish annually for our dinner tables. What will be the size of the catch if the ocean conveyor shuts down?

Using physics and chemistry and ignoring biology to model climate is total folly. It’s like trying to predict the future of a city by calculating the rate of weathering of concrete and rusting of iron while ignoring the activities of man. It is the activity of all living things that determines climate and how these living things manipulate physics and chemistry. As the climate changes the distribution and numbers of species changes and this feeds back into climate and affects the species again.

FUTURE CLIMATE

There are at least three possible advantages for the Earth developing a climate with large volumes of ice at the poles.

• The potential to accelerate the angular velocity of the Earth and possibly regenerate the magnetic field. This might not be theoretically possible.

• A rapid response to changes in the solar constant. While unstable systems are delicate to control they have quick response times. If the solar constant is not as constant as we think it is, then keeping the Earth in a critical state with a large volume of ice and more importantly, ice cover, provides a means of responding rapidly. If solar output increases, the Earth heats up and ice melts, heating the Earth even more. This opens up habitat for plants that sequester more carbon e.g. expansion of the taiga forest. An unlikely piece of logic but we have to be prepared to think outside the square.
• A means of achieving an average ocean temperature which is suitable for creating a global thermo-haline current. This current is important to the fertility of the ocean and land, allowing total photosynthesis to be maximised by establishing global or large regional climatic systems such as the monsoon. It assists in CO₂ control by providing a rapid means of taking the gas down to deep bottom water. (missing graphic is an energy versus temperature diagram for the earth. It is a an arc convex side upwards, and shows the quantity of energy that living things have to manipulate to change the temperature of the atmosphere. The energy is used to either to melt ice or extract CO2 from the air. Both are achieved by plants taking CO2 from the air or respiration of organisms bringing CO2 out of storage eg bacteria acting on soil carbon.)

Life can remain stable at any position on the curve, as long as it is cool enough so that plants can grow. The graph implies that some force is attempting to move the Earth to the extreme right or left but this would only happen if ecosystems change. The change could be randomly generated such as the evolution of an upright walking ape or it could be the result of a genetically programmed cycle. Given the appropriate set of organisms the planet could be stable at any position on the upper part of the curve. The Earth managed to achieve a temperature of around 14 degrees C because it has developed genetic program to manipulate CO₂. Glacial cycles may be part of this genetic program. A possible advantage of the Earth being located at the top of the curve would be a faster response time to a change in solar output. Location near the top gives a greater gene pool of both warm and cold ecosystems.

The new fourth law of thermodynamics provides a mechanism to explain how living things can use energy to improve their environment if given the luck, of a set of initial conditions that are favourable to the laws of chemistry. It does not guarantee the continuation of all species if conditions become unfavourable.
TWO HYPOTHESES
There is no shortage of energy in the universe or on Earth but the technology needed to harvest energy can be extremely sophisticated. There are two large sources of energy available to living things on our planet: sunlight and high temperature heat in the depth of the crust. Photosynthesis as performed by cyanobacteria is incredibly complicated requiring many sophisticated enzymes. Evolution of this feat needed around one billion years of development. At some stage, however, probably in parallel with photosynthesis, life also managed to develop a means of using underground heat. There are only two requirements needed to harvest this energy: marine organisms that form carbonate shells from bicarbonate in the ocean and a subduction process to take this carbonate down to the hot depths of the crust.
These two energy harvesting processes have totally different methodologies. Photosynthesis would have started out as a group process but today it has evolved into an individual process. Harvesting the Earth's heat remains a global process of patient cooperation.
Hypothesis One
Two hypothetical enzymes (they might have identical structure) softrockco and hardrockco with a structure almost identical to rubisco help balance the atmosphere. These enzymes control the metabolism of bacteria and possibly nanobacteria by dictating the rate at which CO₂ is allowed to oxidise calcium oxide and calcium carbonate. The bacteria in rocks use this energy to perform vital processes in the mineral cycles. One of these processes is to even out pressure variations in CO₂.
Reefs are eventually subducted into the Earth’s crust. Some million of years later, frictional heat performs the cement kiln process where the carbonate absorbs energy and decomposes into CO₂ and calcium oxide. The CO₂ enters the atmosphere as gas from volcanic vents. The calcium oxide reacts with other elements in the magma to form minerals such as plagioclase. These basic (basic meaning that the minerals react with water to form alkalis) minerals are a form of energy supply for bacteria in the rocks because the bacteria can extract the energy by using carbon dioxide to form calcium carbonate or magnesium carbonate. This allows the bacteria (probably a number of species working together) to act as a massive CO₂ pressure regulator if they contain a molecule similar to rubisco that controls their rate of energy uptake by controlling the oxidation (using CO₂) of the basic rock minerals.
So now we have two underground systems capable of removing CO₂ from the atmosphere:
CaO + CO₂ ---> CaCO₃ mediated by the hardrockco enzyme ?
CaCO₃ + CO₂ + H₂O ---> Ca⁺⁺ + 2HCO₃^- mediated by the softrockco enzyme ?
Both of these systems give nature a method of smoothing out CO₂ pressure swings and both are only possible courtesy of marine organisms that create carbonate. The presence of rubisco-like gene sequences in soil and archae bacteria has already been established but no one has been able to suggest what these enzymes do. To test the hypothesis we only have to show that both of these bacteria can crank-up their metabolic rates as CO₂ levels rise. Without a specialist enzyme we would expect these organisms to adjust their metabolism in a somewhat linear fashion in response to CO₂ pressure. If hardrockco and softrockco exist then we should see exponential increases in metabolism.
The two reactions above constitute part of what was considered to be chemical weathering. Schwartzman and Volk established that this process is accelerated 1800 times if life is present.
Although this hypothesis sounds preposterous because the net benefit to the environment occurs millions of years later, it uses exactly the same logic as all the rest of the Gaia hypothesis. If the enzymes ron (or equivalent enzymes), softrockco and hardrockco are shown in the laboratory to behave as I have predicted, the evidence for Gaia will be undeniable.
On learning that Philippa Uwins (University of Queensland) was studying nanobes in rock samples taken from kilometres below the seabed, I suggested to her that these organisms could derive energy from using CO₂ to convert calcium oxide into calcium carbonate. Her reply was most encouraging. Electron micrographs revealed that the nanobes were much more likely to be associated with plagioclase rather than quartz and that kaolin booklets were located adjacent to the nanobes and plagioclase. So she agreed that it was likely that nanobes were using CO₂.
Hypothesis Two: Coral keeps the Earth's magnetic field active.
The Earth’s magnetic field has been an enigma for many years, but Glatzmaier and Roberts have a computer model, the Geodynamo, which behaves much as the Earth's field does. This triumph of mathematics and computer power makes an amazing prediction that the outer core spins marginally faster than the mantle and crust.
The length of the day is controlled by currents in the mantle, tidal friction, coral reefs and ice. Reefs grow preferentially in warm waters near the equator and deposit their carbonate where it adds to the Earth’s moment of inertia, and increases the day length (by conservation of angular momentum). When ice at the poles melts some of the mass migrates to the equator and also increases the moment of inertia. As the crust and mantle slow down, this leaves the core spinning at a marginally faster rate. Does this effect have any influence on the magnetic field?
When Michael Faraday learned that electric currents could produce magnetic effects he asked himself if magnetism could produce electric currents. The law of electromagnetic induction was the result of his investigations. I don't know if relative motion between the core and the mantle can induce magnetism but if it does then gaian systems have probably developed the means of manipulating this effect. We can envision a scenario where a diminishing magnetic field upsets bird migration. The lack of birds reduces a marine herbivore leading to the proliferation of a highly sequestering algae, sending the climate on to a lower equilibrium of CO₂. The actual situation will be far more complicated than this and most likely will involve the interaction of hundred of species over centuries, but at least we have some idea of where to start looking.
The figure below demonstrates that for most of its recent history, the Earth has been cool, reflecting a large amount of sunlight into space - not the behaviour that we would expect from a system that should be attempting to maximise photosynthesis. From this we can infer that other needs have taken precedence and there is a reason for this low average temperature.
We can note from the graph (NASA compilation) that when the climate emerges from a glacial cycle the curve is a steep continuous ascent. By contrast the descent is a series of descending steps. Whether this behaviour is essential to, or unrelated to generating currents in the outer core is unknown. From the average temperature change and the steepness of the rising curve we can infer that the transition from one part of the cycle to the other involves a large quantity of ice and a high rate of acceleration to the rotational velocity. Does isostatic rebound in the mantle have some beneficial effect to this wobbly pudding on which we live? (missing nasa graphic below of recent glacial-interglacial temperatures)


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