The Dangers of Gaia
The Gaia (Greek Earth Goddess) hypothesis was proposed by James Lovelock and states that the Earth’s biotic and abiotic components form a single, interacting whole that can be thought of as a single organism. Living organisms have a regulatory effect on the environment, promoting the persistence of life. There are several variants of the hypothesis, some close to being straight forward absurd, others so vague and close to accepted scientific ideas that some people (e.g., Richard Dawkins in his Unweaving the Rainbow) have expressed the view that the hypothesis is superfluous. Dawkins, among others, believes that natural selection (in his view the only mechanism driving evolution, beside neutral drift) has no “foresight” necessary for a Gaia effect to occur, but is restricted to selecting genes on the basis of how they perform in the present environment. Lynn Margulis, on the other hand, well known for her studies demonstrating the symbiotic origin of several cell organelles (such as mitochondria) is a strong supporter of the Gaia hypothesis (although not its extreme version).
I do not wish to discuss the scientific merits of the hypothesis, but want to draw attention to its potential misuse.
An organism consists of many parts (cells, tissues, organs) that do not only interact but interact in such a way that the survival of the organism is guaranteed, by “self-correcting” (homeostatic) mechanisms (e.g., if the temperature in a homeothermic animal becomes too high, or if it is in danger of becoming too high, it is lowered by behavioural or physiological processes). Adherents of the Gaia hypothesis believe that the same must occur on Earth. The danger here of course is the false conclusion that – if Earth heats up, as presently apparently happening – :don’t worry, don’t do anything, Gaia will look after it.
Richard Dawkins, in his Unweaving the Rainbow, tells the story of an “ecologist”, who, at a conference sponsored by the British Open University, in which the possibility of extinction of the Dinosaurs by an asteroid impact was raised, said
This could not have happened, ‘Gaia would not have permitted it’.
Gaia may very well permit the extinction of life on Earth by any mechanism that gets out of hand, and this includes global warming. After all, even an organism can die if its homeostatic mechanisms fail: patients are known to have died of high fever. And that such mechanisms operate at the level of a superorganism comprising the entire Earth, postulated by the Gaia hypothesis, is at least doubtful. I certainly would not bet on it.
On the other hand, the Gaia concept may play a positive role. Let us look at the Earth and its ecosystems in their entirety as a sick patient that needs treatment: Do not only treat the parts that are obviously sick (such as rivers and forests), but get to the bottom of it and treat a sick economic and political system that has lead to the deterioration of the environment. But more on this perhaps in a future post.
April 23rd, 2007 at 12:08 pm
My “Model” of Gaia which accurately represents most recent scientific understanding, is that the biosphere *As A Whole* is impervious to both large asteroidal impacts and the absolute worst imaginable global warming. In fact, large asteroidal impacts are absolutely crucial to the biosphere’s natural reproduction (to seed other planets with bacteria). And severe global warming may act to extinguish (or dramatically reduce the population of) the species that is the primary cause, thus having a long term natural fix to the problem. The main long term threats to “Gaia” by this understanding are the “death” of our sun, or “nearby” star explosions.
April 23rd, 2007 at 12:28 pm
This “Model” certainly looks interesting. I don’t know how accurately it represents “most recent scientific understanding”, but do you suggest seriously that we should deliberately ignore the effects global warming might have on the survival of human civilization, because we can be assured that some flora and fauna might survive and start the slow rise to “prominence” again?
Concerning the crucial importance of large asteroid impacts for seeding other planets: well, perhaps, perhaps not. To my knowledge (but I have not kept up with the literature), nobody has provided evidence yet that bacteria spread through space, although it may well be possible. Can you supply any references? I would be very much interested and grateful.
April 23rd, 2007 at 2:20 pm
I don’t know where the “might” comes into it (*will* survive). In my way of thinking, Dinosaurs etc. (all the species that extincted at that time) were not “necessary” for the biosphere’s existence. In fact they could be seen like a cancerous growth that was cut out by the asteroid. This made way for lots of niches for further specialised speciation. The end of civilisation as we know it could make way for a myriad of species in a new beginning for the Biosphere. Of course I think global warming has a vanishingly small probability of being the vehicle of our destruction, but it heartens me that we will probably deserve whatever destruction befalls us.
Well, I find the tracking of references tedious, but these are the elements (Google might help if you are interested to find citations).
Bacteria on helmet of lunar space suit survived the vaccuum, cold etc of space and reactivated when back on earth.
Martian meteorite has fairly extensive circumstantial evidence of bacteria with Martian origin (ie not proven beyond reasonable doubt but consistent with)
The fact that meteorites survive fairly intact from one planet to the next in itself is evidence of possible exchange of genetic material (whether it be virus, bacteria, RNA or whatever building blocks)
Bacteria in the troposphere? in a zone which has no mixing with lower areas of the atmosphere has been asserted to be explained by extra-terrestrial origin.
The fact that the freezing and re-thawing of single-celled organisms (including human embryos) does not damage the organism of itself as a *general* trait of a wide swathe of those organisms.
Hard evidence (I would rate all of this evidence as circumstancial but convincing) will have to wait for some sample returns from say Mars or certain comets which could harbour detectable quantities.
It would be an interesting experiment to simulate the environment for a target bacteria, and see if it survives a simulated transmission.
April 23rd, 2007 at 3:45 pm
There is no possible way that Global Warming could imperil the survival of human civilisation. This is silliness of the same order as the Creationist theme park. If all the carbon dioxide and methane bands were totally saturated, the average global temperature would rise no more than 10 degrees. Humanity and the biosphere as a whole can readily adapt even to such an extreme case, given the range of climates in which human civilisation and life in general currently flourish. The chance that some runaway positive feedback mechanism exists that would make things worse than this is statistically nil, since in geological time it is a near certainty that volcanoes or methane hydrate ‘burps’ have released equivalent amounts of greenhouse gases over equivalent short periods.
I assert that the economic and political system we have now in the West has given markedly improved environmental conditions in the developed world over the past fifty years, and is likely to deliver these improvements worldwide if allowed. It is not a ‘disease’ from which a prostrate biosphere is suffering. Attempts to ‘treat’ this economic and political system delivered only human and environmental catastrophes to the 20th century.
April 23rd, 2007 at 5:23 pm
Chris: Concerning the economic/political system: I would be delighted if you were right but have my doubts: probably half the world’s population at this point in time would be skeptical, but - as you suggest- given enough time, they might change their mind. Concerning the effects of global warming on civilization: civilization is a very fragile thing, and nobody knows how it would react to a stress never experienced before. But again, I would be delighted if you were right. I certainly would suggest not to be too dogmatic about it.
April 24th, 2007 at 9:11 am
I think the environmental movement has succeeded in selling disaster as likely (given BAU) by pushing that certain other things like links as a scientific certainty - This confuses the masses and the masses put the two together and think there is a certainty of disaster with BAU. There is a near certainty of climate change, and there is a vanishingly tiny possibility that this would cause civilisation threatening disaster. Put the two together, and the conclusion is we don’t want to punish environmental laggards with thermonuclear war. Thermonuclear war is civilisation threatening, and tensions between countries due to climate issues should be downplayed with a view that avoiding large scale wars is more important than standards in reduction of CO2.
April 24th, 2007 at 11:45 am
“Thermonuclear war is civilisation threatening, and tensions between countries due to climate issues should be downplayed with a view that avoiding large scale wars is more important than standards in reduction of CO2.”
But this is exactly the point: I don’t think that climate change per se, leading to a global temperature rise of a few or even several centrigrades, would lead to the extinction of our civilization, but thermonuclear war triggered by such rise may. I made this point earlier in a comment on one of my posts, and the point that we face war, if action against global warming is not taken now, was also made by high ranking US generals (although they did not specifically mention thermonuclear war). Atom bombs have been used, and they will be used again if we have the wrong people at the top of powerful nations whose standard of living is threatened for example by uncontrolled large scale population movements.
April 24th, 2007 at 12:17 pm
Marco: Concerning transfer of bacteria through space. I don’t think your references are conclusive (and you don’t claim they are). I also assume that you do not have access to the Web of Science. I therefore made a brief survey of relevant references in the Web, although I don’t have the time to make a thorough search. I found two references. You will note that one identifies a terrestrial bacterium on the surface of a spacecraft (genus Bacillus) (but as suggested by the Abstract, before it went into space), the other deals with experiments important for potential transfer of microbes from Earth to elsewhere in space. None of the two demonstrates transport of bacteria from space to Earth, but I think it is quite possible, if the following requirements are fulfilled: 1) there is bacterial life on other planets within our solar system; and there are mechanisms which can cause transfer or, 2) if not, that bacteria can survive transport from outside the solar system. I am not aware of any findings which provide evidence for this, but we should keep an open mind and look for it. The second paper below seems to suggest that such evidence does in fact not exist.
Bacillus safensis sp nov., isolated from spacecraft and assembly-facility surfaces
Satomi M (Satomi, Masataka), La Duc MT (La Duc, Myron T.), Venkateswaran K (Venkateswaran, Kasthuri)
Source: INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 56: 1735-1740 Part 8, AUG 2006
Abstract: Thirteen strains of a novel spore-forming, Gram-positive, mesophilic heterotrophic bacterium were isolated from spacecraft surfaces (Mars Odyssey Orbiter) and assembly-facility surfaces at the Jet Propulsion Laboratory in California and the Kennedy Space Center in Florida. Phylogenetic analysis of 16S rRNA gene sequences has placed these novel isolates within the genus Bacillus, the greatest sequence similarity (99-90%) being found with Bacillus pumilus. However, these isolates share a mere 91(.)2 % gyrB sequence similarity with Bacillus pumilus, rendering their 16S rRNA gene-derived relatedness suspect. Furthermore, DNA-DNA hybridization showed only 54-66 % DNA relatedness between the novel isolates and strains of B. pumilus. rep-PCR fingerprinting and previously reported matrix-assisted laser desorption/ionization time-of-flight mass spectrometry protein profiling clearly distinguished these isolates from B. pumilus. Phenotypic analyses also showed some differentiation between the two genotypic groups, although the fatty acid compositions were almost identical. The polyphasic taxonomic studies revealed distinct clustering of the tested strains into two distinct species. On the basis of phenotypic characteristics and the results of phylogenetic analyses of 16S rRNA and gyrB gene sequences, repetitive element primer-PCR fingerprinting and DNA-DNA hybridization, the 13 isolates represent a novel species of the genus Bacillus, for which the name Bacillus safensis sp. nov. is proposed.
TTitle: Testing interplanetary transfer of bacteria between Earth and Mars as a result of natural impact phenomena and human spaceflight activities
Fajardo-Cavazos P (Fajardo-Cavazos, Patricia), Schuerger AC (Schuerger, Andrew C.), Nicholson WL (Nicholson, Wayne L.)
Source: ACTA ASTRONAUTICA 60 (4-7): 534-540 FEB-APR 2007
Abstract: Interplanetary transport of microbes between Earth and Mars can be envisioned to occur either naturally as a consequence of impacts (lithopanspermia) or as a result of human and robotic spaceflight. in either case, the considerations for modeling successful transfer of microbial life are similar.The probability of microbes surviving either natural or human-mediated transfer is a function of: the initial population size and composition (i.e., the bioload); survival of launch, transit through space, entry and deposition; and ability to survive and proliferate on the recipient planet. Modeling this process for testing lithopanspermia and for mitigation of forward and back contamination for planetary protection purposes calls for accurate simulation of all aspects of transfer.
April 24th, 2007 at 2:14 pm
I don’t see how we could seriously “blame” thermonuclear war on climate change. Hatred and fear between enemies without a suitable mediating system is the more general cause - Any of a myriad of important issues could trigger a “hot” war. In fact, concerns about climate change are giving potential proliferators cover because of its carbon neutrality! I find Geopolitical issues to be of considerable importance to everybody’s future. I find the arguments about climate change a sad joke in comparison.
April 24th, 2007 at 2:32 pm
As far as the lithopanspermia is concerned, I think scientists concerned are loth to challenge the theory of terrestrial origin of life as we know it. At least until the evidence is completely irrefutable. There are plenty of suitable sites on Mars which should have both fossils of bacteria from when there was liquid water there, and subterranean extremophiles of some sort. I am very certain that these will be found (hopefully in our lifetime). There are also several other places in the solar system to look as well, but that might not happen in the foreseeable future. Until then, the missing evidence will be an article of faith, at least for me.
April 24th, 2007 at 3:12 pm
Thermonuclear war: well said, but what is responsible for the hatred and fear? Potential proliferators: Pakistan, India and Israel did not need any cover, the first two did it quite openly, the last not so openly.
Suitable mediating system: well said, the first step should be to make all nations, even the most powerful, acknowledge internationally binding treaties on nonproliferation and accept all their conditions, and commit themselves to non-aggression by any weapons.
“I find the arguments about climate change a sad joke in comparison”. Well said, serious effects of climate change are indeed still in the future, I would suggest that the greatest danger at present is the rush to secure oil (and other energy) supplies.
April 24th, 2007 at 4:30 pm
Lithopanspermia: I am puzzled and intrigued by your use of “faith” in this context. Is this just a vague expression or does it indicate that presence throughout the Universe of life forms is somehow part of your religious or philosophical beliefs ? After all, Fred Hoyle had such “beliefs” in the context of his steady state theory of the Universe.
April 24th, 2007 at 5:32 pm
In this case, it (faith) is what I believe will eventually be scientifically proven truth. In that single-celled extremophiles are spread throughout the galaxy from an unknown original source. If there is strong evidence to the contrary, this faith would be shattered (but it won’t be)
April 24th, 2007 at 5:53 pm
Geopolitics: Are the world bodies as they stand a suitable shell of a system that might work? Maybe. They seemed to work reasonably with respect to the Balkans, East Timor and perhaps Gulf War I. It appeared the separation of powers required was that the UN was in the law making arm, the US was the law enforcement arm and a special World court seems to make a pretty good judiciary arm of world law. This system is a shambles in general for Middle Eastern countries. “Criminal” countries can be at the same time “victims” of police action. But like inside individual countries, it doesn’t make the criminals any less criminals. I think even with its perceived misdeeds, no other entity can hope to match the US’s ability to enforce world law when it becomes reality. A world order that formalises these separations of powers can have hope at preventing disastrous conflicts.
April 24th, 2007 at 6:08 pm
The requirement to secure energy supplies is illusion and spin. If an unfriendly country interrupts supply, they lose the income for that supply. Energy can almost entirely be controlled with economic means. Energy taxes can be used to reduce demand if we think reducing demand is a good idea. Security is only an issue because people like to feel secure. There will always be enough energy to do what we want to do. We just might not be able to afford it in all situations.
April 24th, 2007 at 6:12 pm
Faith: the question is: why do you think there is a single original source, why not many?
April 24th, 2007 at 8:05 pm
Venturing an answer to the ’single original source’ question, which Marco may contradict: Given a reasonable mechanism of dispersal, one might expect the first form of life to arise to rapidly adapt to its surroundings and spread widely. As it does so, it will make it much more difficult for an entirely novel form of biology to arise anywhere it colonises because of its efficient use of possible chemical substrates. It appears that only DNA-based life exists on our world, and that this has been the case for at least 500 million years: it seems probable then that either no different forms of life have arrived here during this time, or that if they have they have been efficiently outcompeted by DNA-based life. Unless we are to claim that Earth life has exceptional competitive powers which other hypothetical DNA-based life lacks- which I am loathe to do- the uninterrupted 500 million year+ history of terrestrial life and the dimensions of our galaxy suggest that there are no other effective centres of dispersal in our galaxy.
There is probably a clearer way to state this argument- I will try again later!
April 24th, 2007 at 8:15 pm
‘Loathe to do’ only because of the ‘assumption of mediocrity’ which like ‘entities must not be multiplied beyond necessity’ is of course only a guideline, not an infallible indicator of truth…
April 24th, 2007 at 10:57 pm
The single point of origin is in a sense my feeling of there being a common ancestor amongst all DNA based lifeforms. There is a strong case in my mind that DNA based life is in fact evolved in particular for planet-hopping. Other types of life that couldn’t *as a category* survive the transfer would become extinct along with its host planet. The fact that even human embryos can stay viable indefinitely frozen is an important fact in my thought experiment. It appears even a life-form that has strayed a long way genetically from a typical planet-hopper, still retains the freeze/thaw option in its embryonic stage. The conventional wisdom is that if life formed from nothing here on earth it may easily have happened on a large swathe of the universe’s planets. I am of the opinion that there is both competitive pressures between possible origins as well as between species and the one that can most successfully reproduce and disseminate has won out.
April 25th, 2007 at 11:26 am
Since we have now sorted out how you believe life has originated and spread through space, a few words on
“The requirement to secure energy supplies is illusion and spin. If an unfriendly country interrupts supply, they lose the income for that supply.”
This is obvious, but history shows that countries like to have their hands on the supplies rather than being dependent on countries that might one day become unfriendly. And this preference for controlling supplies has repeatedly led to wars. Not unimportant: controlling supplies instead of just buying them may increase profits. Shell’s and Exon’s practical “ownership” of Iraq’s oil supplies, for example, would have definite economic advantages for these companies. Russia knew what it was doing when it restricted ownership of Eastern Siberia’s gas supplies by foreign companies ( I think Shell) to below 50% or so.
“a special World court seems to make a pretty good judiciary arm of world law” Good idea, we can only hope that the US will recognize it (that is, not just for others but for itself as well).
” I think even with its perceived misdeeds, no other entity can hope to match the US’s ability to enforce world law when it becomes reality. A world order that formalises these separations of powers can have hope at preventing disastrous conflicts.” I don’t think Russia and China will like that idea. And for good reasons. How does the old saying go?: power corrupts, and absolute power corrupts absolutely (see the present attempts by Bush to keep Wolfowitz in office as the World Bank President in spite of his corruption).