Implications for Climate Change Policies
New research shows oxygen depletion in the atmosphere accelerating since 2003, coinciding with the biofuels boom; climate policies that focus exclusively on carbon sequestration could be disastrous for all oxygen-breathing organisms including humans Dr. Mae-Wan Ho
Threat of oxygen depletion
Mention climate change and everyone thinks of CO2 increasing in the atmosphere, the greenhouse effect heating the earth, glaciers melting, rising sea levels, floods, hurricanes, droughts, and a host of other environmental catastrophes. Climate mitigating policies are almost all aimed at reducing CO2, by whatever means.
Within the past several years, however, scientists have found that oxygen (O2) in the atmosphere has been dropping, and at higher rates than just the amount that goes into the increase of CO2 from burning fossil fuels, some 2 to 4-times as much, and accelerating since 2002-2003 [1-3]. Simultaneously, oxygen levels in the world’s oceans have also been falling [4] (see Warming Oceans Starved of Oxygen, SiS 44).
It is becoming clear that getting rid of CO2 is not enough; oxygen has its own dynamic and the rapid decline in atmospheric O2 must also be addressed. Although there is much more O2 than CO2 in the atmosphere - 20.95 percent or 209 460 ppm of O2 compared with around 380 ppm of CO2 – humans, all mammals, birds, frogs, butterfly, bees, and other air-breathing life-forms depend on this high level of oxygen for their well being [5] Living with Oxygen (SiS 43). In humans, failure of oxygen energy metabolism is the single most important risk factor for chronic diseases including cancer and death. ‘Oxygen deficiency’ is currently set at 19.5 percent in enclosed spaces for health and safety [6], below that, fainting and death may result.
The simultaneous decrease in ocean oxygen not only threatens the survival of aerobic marine organisms, but is symptomatic of the slow-down in the ocean’s thermohaline ‘conveyor belt’ circulation system that transports heat from the tropics to the poles, overturns surface layers of into the deep and vice versa, redistributing nutrients and gases for the ocean biosphere, and regulating rainfall and temperatures on the landmasses. This dynamical system is highly nonlinear, and small changes could make it fail altogether, with disastrous runaway effects on the climate [7] (Global Warming & then the Big Freeze, SiS 20). More importantly, it could wipe out the ocean’s phytoplankton that’s ultimately responsible for splitting water to regenerate oxygen for the entire biosphere, on land and in the sea [4].
Measuring O2 to better understand the earth’s carbon budget
Global CO2 records go back more than 50 years [8], but O2 measurement in combination with CO2 goes back barely two decades [9], and is already giving important information on the size of the carbon sink in the ocean relative to the land. For one thing, O2 and CO2 have very different solubility in seawater; while 99 percent of the O2 remains in the atmosphere, 98 percent of the CO2 is in seawater.
O2 and CO2 are exchanged in different processes on land, each having a different O2:CO2molar exchange ratio and thus distinguishable from one another. Fossil fuel combustion has a global average O2:CO2exchange ratio of about 1.4 moles of O2consumed per mole of CO2produced, whereas land plant photosynthesis generates an average net ratio of about 1.1 moles of O2 for each CO2fixed. These ratios can vary over spatial and temporal scales, depending on whether photosynthesis produces more oxygen than is consumed by respiration, and on the precise fossil fuel burnt (see later). The linkage between CO2 and O2 is broken, however, at the air-sea interface, where substantial O2 fluxes may be unaccompanied by fluxes of CO2 and vice versa.
By knowing the fossil fuel emissions and the exact value of the exchange ratios, one can separate the total CO2 uptake into land and ocean components on timescales of a few years. This has led to estimates of the land and ocean sinks to be 0.5 and 2.2 GtC/year respectively for the periods 1993 to 2003, with a fossil fuel increase rate of 6.5 GtC/y [10]. (see Box 1 for details on the calculations.)
A new atmospheric station has been established on the North Sea oil and gas production platform F3, 200 km north of the Dutch coast, which measures both CO2 and O2 continuously using the latest fuel cell and infrared technologies [11], and more precise data on sea-air exchanges are anticipated.
Measuring O2 and calculating land and ocean carbon sinks
It is difficult to measure changes in O2 because there is so much of it in the atmosphere compared with CO2. So a proxy is used instead. Changes are measured as differences in O2/N2 ratios expressed in “per meg” units against the ratio in a standard mixture kept at the Scripps Institute of Oceanography, La Jolla California in the USA, which pioneered the measurement.
D(O2/N2) per meg = 106[(O2/N2)sam - (O2/N2)]ref/ (O2/N2)]ref (1)
This difference is used to define O2 concentration: 4.8 per meg are equivalent to 1 ppm (i.e., 1 mmole O2 per mole of dry air). By making the assumption that atmospheric N2 concentrations are constant, this definition of O2 concentration can be applied to derive O2 fluxes as follows [9, 10].
An Atmospheric Potential Oxygen (APO) is defined, also in per meg units, as the sum of oxygen as determined n eq. (1) and the oxygen that went into producing the CO2 in the atmosphere.
APO per meg = D(O2/N2) + aB 4.8[CO2] (2)
where aB represents the O2:CO2 exchange ratio for land photosynthesis and respiration; and [CO2] is the concentration of CO2 in the atmosphere. This assumes that variations in APO can only be caused by air-sea exchanges of O2, N2 and CO2, and by combustion of fossil fuels.
Oceanic uptake of atmospheric CO2, however, reduces the observed upward trend in atmospheric CO2 concentrations, but has no effect on the observed downward trend in O2/N2 ratios. Thus the global budgets for atmospheric CO2and O2can be respectively represented by eqs (3) and (4).
DCO2 = F – O – B (3)
DO2 = aFF + aBB + Z (4)
Where DCO2 is the globally averaged observed change in atmospheric CO2 concentration, DO2 is the globally averaged observed change in atmospheric concentration, F is the source of CO2 emitted from fossil fuel combustion (and cement manufacture), O is the oceanic CO2 sink, B is the net land biotic CO2 sink (including biomass burning, landuse change and land biotic uptake); aF and aB are the global average O2:CO2 exchange ratios for fossil fuels and land biota respectively, and Z is the net exchange of atmospheric O2 with the ocean. All except exchange ratios are in units of moles per year.
Combining eqs 2, 3 and 4 gives:
DAPO = (-aF + aB)F – aBO + Z (5)
where DAPO is the globally averaged observed change in APO. Eq. 5 is used to obtain the oceanic sink, and then eq 3 is used to obtain the land biotic sink. This gives less uncertainty, as APO is less variable than the O2/N2 ratios.
Large decreases in atmospheric oxygen detected
Decrease in atmospheric O2 has been detected in stations around the world for the past decade, a consistent downward trend that has accelerated in recent years.
The largest fall in O2 was observed in the study of Swiss research team led by Francesco Valentino at University of Bern, for data collected at high altitude research stations in Switzerland and France. The Jungfraujoch (JFJ) station in Switzerland (3 580 m above sea level, 46o 33’N, 7o 50’E) is located on a mountain crest on the northern edge of the Swiss Alps. The Puy de Dôme station (1 480 m above sea level, 45o46’N, 2o 58’E) is situated west of the Alps at the summit of Puy de Dôme.
The research team confirmed the general upward trend for atmospheric CO2 and a downward trend in atmospheric O2. But since 2003 for JFJ, and mid 2002 for at Puy, there is a significant enhancement of O2 and CO2 trends compared to previous years. At JFJ, the rate of CO2 increase shifted up from 1.08 ppm (parts per million) for the years 2001-2002 to 2.41 ppm/y for 2003-2006; while the increase in D(O2/N2) and APO (measures of oxygen concentration, see Box 1) shifted downwards to greater extents from –2.4 ppm/y and -1.5 ppm/y to -9.5 ppm/y and -6.9 ppm/y respectively.
For Puy, CO2 increase changed from 2.43 ppm/y for 2001-2002 to 1.07 ppm/y for 2003-2004, followed by 2.4 ppm/y for the years 2005-2006; while the changes in D(O2/N2) and APO were -6.1 ppm/y and -3.7 ppm/y for 2001-2002, to -10.4 ppm/y and -7.6 ppm/y for the years 2002-2006. Averaged over all years – by removing the trends and plotting correlations between CO2 and O2, an O2:CO2exchange ratio of -1.9+0.7 is found for JFJ, and -1.8+0.5 for Puy; both significantly different from the 1.1 assumed for land photosynthesis and respiration i.e., 1.1 mole of O2 generated per mole of CO2 fixed, and -1.4 for burning fossil fuels, or 1.4 mole of O2 used up when one mole of CO2 is produced.
Over time, the O2:CO2exchange ratio for JFJ, which is much less exposed to local or regional anthropogenic influence because of its elevation and location, was -2.1+0.1 for the years 2001-2002 and -4.1+0.1 for the years 2003-2006. At Puy, the ratio was -4.2+0.1 for the period 2001-2003, and -7.3+0.1 for 2003-2006. These ratios are completely out of line with what could be expected from fossil fuels, and other data indicate that there has been no significant change in fossil fuel emission rates during the period 2003-2006.
The researchers speculated that the large decrease in atmospheric oxygen since 2003 could have been the result of oxygen being taken up by the ocean, either due to a cooling of water in the North Atlantic, or water moving northwards from the tropic cooling, both of which would increase the water’s ability to take up more oxygen. However, it would require unrealistic cooling to account for the change in O2concentration. And all the indications are that the ocean waters have warmed since records began [4].
In a second study, atmospheric O2 and CO2 data collected from two European coastal stations between 2000 and 2005 were analyzed [2]. Mace Head Ireland (53o20’N
9o54’W, 35 m above sea level), which serves as the marine background, relatively free from local fossil fuel consumption, and Station Lutjewad (53o24’N, 6o21’E) on the northern coast of The Netherlands 30 km to the northwest of the city of Groningen, which serves as a continental station receiving continental air with northerly winds. Similar trends were detected. Over the entire period at Lutjewad, CO2 increased by 1.7+0.2 ppm/y while oxygen decreased at -4.2+0.3 ppm/y; the corresponding figures for Mace Head were 1.7+0.1 ppm/y and -4.0+0.3 ppm/y. O2 is decreasing faster than can be accounted for by the rise in CO2. Furthermore, the decrease is not uniform throughout the entire period; instead it is much steeper between 2002 and 2005 at both stations, and is not accompanied by any change in the trend of CO2 increase. This sharp acceleration in the downward trend of atmospheric O2 from 2002-2003 onwards in Ireland and The Netherlands is in accord with the findings in Switzerland and France [1]. And this cannot be explained by a realistic increase in fossil fuel use, or oxygen uptake by cooler ocean waters; if anything, oxygen level in the oceans has also been falling [4]. So where and what is this oxygen sink that is soaking up oxygen?
Mystery of the oxygen sink
One distinct possibility that has been considered is that an extra oxygen sink has opened up on land as the result of human activities.
James Randerson at University of California Irvine was lead author on a report published in 2006 [12] pointing out that a decrease in atmospheric O2 could result if carbon within the land biosphere becomes more oxidized (sequestering more oxygen) through disturbance of natural ecosystems. This has changed the natural land cover, replacing it with plants that effectively remove more oxygen from the atmosphere.
Atmospheric exchange of O2 with land ecosystems is commonly expressed in terms of a net carbon flux from the atmosphere to the ecosystem (Fnet) and the net O2:CO2exchange ratio (Rnet):
dO2/dt = - Rnet Fnet (6)
By convention, positive sign indicates release into the atmosphere and negative sign sequestered in the land biosphere. The net rate is really a difference between two processes, one moving from atmosphere to biosphere, and the other in reverse, from biosphere to atmosphere, so eq. (6) can be written as follows.
dO2/dt = - (Rab Fab + RbaFba) (7)
where Fab is the atmosphere to biosphere carbon flux (the same as net primary productivity, NPP), Rab is the oxidative ratio related to NPP (moles O2 released per mole CO2 fixed), Fba is the biosphere to atmosphere return flux (a combination of respiration, fires and other losses), and Rba is the oxidative ratio related to the return flux (moles O2 consumed per mole CO2 released).
In an ecosystem at steady state (in dynamic balance), Fab and Fba will have the same magnitude. But the carbon in Fba is always offset in time from newly assimilated carbon in Fab because of carbon storage in the plant, dependent on plant tissue lifetimes, rates of litter and soil organic matter decomposition, and so on. Changes in Rab and Rba have the potential to cause relatively large changes in atmospheric O2, basically because of the time delays between fixation and the return flux due to carbon storage. The longer the carbon storage (turnover) time, the larger the effective offset between Fab and Fba; so O2 is consumed at a slower rate, and more of it remains in the atmosphere
Randerson and colleagues hypothesize that increasing levels of disturbance across natural ecosystems in recent decades has decreased Rab. This includes wide-spread deforestation and replacement of woody vegetation with pastures and crops in the tropics, an increase in fire activity and tree mortality and increasing the abundance of deciduous tree species and herbaceous plants in the boreal (northern) regions. Globally, this includes an increase in invasive species and increased disturbance of agricultural soils by plowing and grazing during the 20th century. All these activities increase the oxidation state of carbon in plant and soil organic matter. The increases in oxygen content of the resultant biomass causes a small sink for atmospheric O2 that has not been accounted for in atmospheric budgets.
Within a plant, lipids and lignin compounds have carbon that is more reduced, i.e., with more hydrogen and less oxygen; they have and large R values of 1.37 and 1.14 respectively, and are energetically more costly to build than compounds such as cellulose and starch, which have less hydrogen, more oxygen, and R value of 1.0. Thus, the expansion of agriculture and grazing during the 20th century has probably caused a decrease in the oxidative ratio of the plant biomass within these disturbed ecosystems. Using several simple models, the researchers showed that, indeed, small changes in Rab could lead to substantial decreases in atmospheric O2.
Another research team has raised the possibility that reactive nitrogen produced in making artificial fertilizers for agriculture could also be tying up more oxygen in plant tissue, soil organic matter and oceans in the form of nitrates [13].
The importance of oxygen accounting in climate policies
Change in land use, and increased oxidation of nitrogen could explain the long term steady decline in atmospheric O2, and may well also account for the sharp acceleration of the downward trend since 2002 and 2003.
These years happen to coincide with record rates of deforestation. In Brazil, 10 000 square miles were lost mainly to pasture land, soybean plantations and illegal logging, a 40 percent rise over the previous year [14]. Massive deforestation has continued in the Amazon and elsewhere, spurred by the biofuels boom [15]; it is estimated that nearly 40 000 ha of the world’s forests are vanishing every day.
The crucial role of forests and phytoplankton [4] in oxygenating the earth shows how urgent it is to take oxygen accounting seriously in climate policies. Reductionist accounting for CO2 alone is insufficient, and even grossly misleading and dangerous.
A case in point is the proposal of the International Biochar Initiative (IBI). ‘Biochar’ is charcoal produced to be buried in the soil that IBI has been promoting worldwide over the past several years [16] as a means of sequestering carbon from the atmosphere to save the climate and enhance soil fertility. It involves planting fast growing tree and various other crops on hundreds of millions of hectares of ‘spare land’ mostly in developing countries, to be harvested and turned into charcoal in a process that could produce crude oil and gases as low grade fuels. There are many excellent arguments against this initiative [17], but the most decisive is that it will certainly further accelerate deforestation and destruction of other natural ecosystems (identified as ‘spare land’). In the process, it could precipitate an oxygen crisis from which we would never recover [18] (Beware the Biochar Initiative, SiS 44).
There are 23 comments on this article so far. Add your comment
Su Comment left 21st August 2009 10:10:12
Thanks Mae-Wan, Tried locating the Green Farm 2 but couldn't find it, could you perhaps send me a link? Cheers Su
mae-wan ho Comment left 21st August 2009 10:10:16
Hi Su, It is Dream Farm 2, not Green Farm. here is one link, but there are others: http://www.i-sis.org.uk/HowtoBeatClimateChange.php
Julian Rose Comment left 29th August 2009 13:01:16
What I think we can all agree upon is the fact that 'grand schemes' (like biochar, ocean dumping of iron chips and reverse osmosis sea funnels) are, as Einstein once pointed out 'using the same kind of thinking that produced the problem in the first place'. We have to change that way of thinking all together and move into a fourth dimensional understanding of the subtle interrelationship that exists between all living matter - of which we are also a part. Eve Balfour (a soil scientist) pointed out back in 1947, that the robust natural 'health' of man and the soil depended upon a perpetuation of the dynamic cyclic interrelationship and subtle symbiosis of soil, plant, animal and man. Break or upset this chain at any one point and the other three dimensions will be thrown out of line. We can only respect this simple wisdom by refinding our (human's) place in nature and re-attuning ourselves to the universal forces that gave birth to us in the first place. All other approaches will only serve to further perpetuate the problem.
James A Robey Comment left 30th August 2009 18:06:17
Interestingly, one of the most outspoken early proponents of concern over dropping O2 levels was Stanley Meyer, who developed an efficient way to convert water into hydrogen fuel. He proposed that an immediate conversion of carbon fueled cars, trucks, etc., to hydrogen fuel made from water would attend this problem. On page 108 of the book "Water Car - How to Turn Water into Hydrogen Fuel!" is a copy of page 2 of his US Patent # 4,936,961. You will notice on lines 22-23 of this patent reference that he makes mention of "other gases...formerly dissolved within the water..." One of these is O2, which means that when you convert water to fuel and burn it, a small amount of excess O2 is released to the atmosphere! Now multiply that times the number of fuel burning devices worldwide. Get the picture?
Mae-Wan Comment left 20th August 2009 07:07:03
Earl Davis, why yes, this possibility has been raised in the earlier article Warming Oceans Starved of Oxygen.
Helen Thornton-Mutiso Comment left 20th August 2009 07:07:49
In Kenya we are starting to make bio-fuels from the seeds of Indigenous Hardwood TREES, Croton megalocarpus and calodendrum capenses. A mature Croton tree drops about a tonne of seed a year, and they are already all over the country. A tree strated producing seed in year three... Each tree can give a revenue of around $50 per year to a rural farmer. This helps more trees to be planted and protected. BioFuels themselves are not bad, only when they are made from agricultural crops or Jatropha....
andré Comment left 19th August 2009 15:03:25
it is time to think systematically instead of our reductionistic way of thinking.......
Tom Blakeslee Comment left 19th August 2009 17:05:47
Carbon Capture and Sequestration (CCS) may be a disaster for Oxygen becaise more Oxygen than carbon is buried when CO2 is sequestered. The US is spending billions to develop this disastrous approach that sequesters twice as much oxygen as carbon.
Ninette Comment left 19th August 2009 16:04:07
A lack of o2, so is that why people have been so easily dupped into thinking change is something to get from a political party agenda--Hello wake up and breath folks change comes from within...
mindor Comment left 19th August 2009 17:05:33
How will this trend affect cabin O2 tensions when at 35,00 to 40,000 feet? Do the aircraft that daily travel these circumpolar route every keep records?
Jon Anderholm Comment left 19th August 2009 17:05:12
A definite reason to reforest the planet... Restoration of the Earth's forest cover... Wouldn't this address this O2 dilemma???
Mae-Wan Ho Comment left 19th August 2009 17:05:13
andre, spot on. ISIS is dedicated to promoting holistic joined up thinking. Tom Blakeslee, that's a good point, but there is no evidence the CO2 will stay stored, and more fossil fuels will be burnt, which is also bad for oxygen, Mindor, cabin O2 pressure should not be affected, but it may be kept too low anyways Jon Anderson, Yes, but we have to firmly reject monoculture forest plantations or fast growing softwoods
Earl Davis Comment left 19th August 2009 18:06:11
I once wrote a script for a disaster type movie about a Gaia catastrophe cascade (in an effort to get the positive Gaia science into general circulation). It began with a generator shutting down at an Antarctic research station for lack of oxygen - the reason being a massive die-off of ocean phytoplankton due to combination of uv increase (from ozone hole) and ocean acidification. Any chance some real phytoplankton die-off might be responsible now? And are there any chart projections of decreasing o2 rates as with co2?
Donald Leenknegt Comment left 26th August 2009 16:04:55
Carbon is the element from which life, and ultimately the Earth's life support system, spiralled into existence. If Carbon is the element of life, Photosynthesis is the engine of life. And there is no other real source of atmospheric oxygen than Photosynthesis, "Photosynthesis is the source of all the oxygen in the atmosphere." It was Photosynthesis which created the Earth's climate. Without Photosynthesis there wouldn't be a climate on Earth - the Earth would be dead like Venus and Mars. Photosynthesis is the crucial element in the Earth's life support system and the key means of stabilizing the Earth's climate. Without Carbon, there would be no Photosynthesis, but without Photosynthesis there would be: no oxygen in the atmosphere, no stratospheric ozone layer, no hydrogen, no water, no oceans, no continents, no Carbon burial, no Carboniferous rock formations, no layers of coal, nor oil deposits, no Plants or Trees, no food, no soils, no Wildlife habitats, no Wildlife, no climate, and no stable climate. In sum, no life. Satellite measurements have shown that in the last 20 years biomass on earth has increased with 6%, probably due to the increased carbon content of the atmosphere. Life was most prolific in the distant past when there was 5 to 10 times as much CO2 in the atmosphere as now, with very little influence on the temperature of the planet. A little bit more CO2 in the atmosphere can not be the cause or the problem we are facing. So, I agree: let us look for other causes linked to the human activities on this green planet earth.
Su Kahumbu Comment left 20th August 2009 13:01:50
Sadly Mae, your suggestion of 'firmly rejecting monoculture forest plantations or fast growing softwoods'would really only be practical in a developed nation that is not dependent on charcoal as a fuel source. In Kenya we are currently struggling with failed rains, no water in the dams, thus no hydro electricity. This has lead to a national rationing of electricity that is crippling the country . The cause.........decimation of our forests. Everywhere you turn people are being told to plant trees, literally any type of trees. Naturally folk will choose the quickest growing and most readily available which is probably blue gum. (and of course cheapest) In its simplistic form we are planting to get water and fire wood (and funnily enough, electricity poles) . Will poverty stricken nations ever be convinced to plant slower growing less available and probably more expensive trees because of the complexities between o2 and co2 levels? Somehow I doubt it. Ironically, we would need to be in some sort of 'comfort zone' before this would be a priority. And even more ironically the 'comfort zone' will probably never become a reality .
Mae-Wan Ho Comment left 20th August 2009 13:01:20
Su Kahumbu, in a forth-coming report, we shall present evidence that soot from making and burning charcoal contributes as much to global warming as greenhouse gases, and there are many solutions to that, by providing better stoves and most of all by using anaerobic digestion to generate methane that's the cleanest fuel around. Please look up "Dream Farm 2" on this site. All these should be part of the climate negotiations, free technology transfer and clean, green development for developing countries. My name is Mae-Wan, not Mae.
Pierre-Louis Lemercier Comment left 21st August 2009 09:09:38
And soon, I believe that we will find many more missing/overlooked links in a near future. It is my humble opinion that the whole system has not been designed on the reality of a life cycle, wherein people, who are parts and parcels of the environment, hence depend on it, know it and therefore should have a say. A system wherein everything is linked and important (not only the CO2 issue), nothing is lost but everything transformed (output from one side becoming input to another side -like sustainable amount of CO2 recycled into sugar through photosynthesis) to form a perfect sustainable cycle. The CC response is being presently designed in the ether by people who lost tough with the real nature of a sustainable environment and some who just use this opportunity to create useful loopholes. Hence they just work on the GHG air content (as GHG alone is the problem) outside its framework, which is the life cycle, hence overlooking many important intervenient and factors in the big environmental equation. As the latter could be simplified to the point that X CO2 amount reduced=saved planet while this is never going to happen if the whole unsustainable present system is not reviewed, scale down into a low carbon system, which can fit again into the environmental cycle. The only way to succeed this is to see the big picture, simplify the “recovery system” by just making (by whatever ways) people/companies decrease their unsustainable inputs as well as outputs (not only GHG). But certainly not allow them to burry their mess and/orpay their way out. Or imagine unsustainable system to pull energy, water, mineral, food and other resources from the other side of the world just to keep their comfort, their easy virtual ways to make big bugs and avoid having to depend on their own local resources. Narrow concepts promote bad projects. The CDM funding f.e will finance a huge monoplantation of eukalyptus in DRC. Yes we have to move fast as people are hungry but we could, with a broader vision remain flexible and also replant on the side local and slow glowing trees. In short, our tunnel vision is killing us as it prevents us to see the big picture and recognize the reality and the condition of our survival. Yes this is a tall order now that we went that far badly but I am don’t think we have any other alternatives. This will require a lengthy re adaptation to a world with little or no petrol, which may not necessarily be painful if it is initiated rapidly (as the Transition Culture movement suggests). Regards PL Lemercier – Renewable Energy Centre – Port Elizabeth
Ben Comment left 22nd August 2009 06:06:58
Pardon me, but I seem to be missing something. O2 is apparently dropping at a rate of less than 10 ppm per year. This means after 1,000 years at this rate, we will have reduced Oxygen by a single percent. This is, of course, ignoring that there aren't that many fossil fuels in the world! It also ignores the fact that plants would grow exceptionally well in an atmosphere with 50 times the CO2 that they evolved in. I have rarely seen such a sophomoric analysis. Very detailed, but leaving out small and extremely basic facts that show the problems are orders of magnitude too small to have effects on ANYTHING.
Mae-Wan Ho Comment left 22nd August 2009 06:06:43
Ben, you are missing something. First, O2 is there principally because of carbon storage time,its rate of drop currently is ~10 ppm, but it could well swing further downwards. Second if increase in CO2 is so good for plant growth it could have compensated for O2 falling, but it hasn't. There is also evidence that increase in CO2 does not translate into increase in carbon fixation; instead it could merely speed up the carbon cycle, making forests and other ecosystems less effective in sequestering carbon, thereby making things worse (see previous article More CO2 Could Mean Less Biodiversity and Worse, http://www.i-sis.org.uk/LOG7.php). Speeding up the carbon cycle in the current context is certainly decreasing the carbon storage time. The devil is in the detail and the connections.
Donald Patriquin Comment left 22nd August 2009 18:06:33
So why do we not see this vital information in the headlines of our daily newspapers? Are we lemmings? Where is the interface between science and politics, between scientists & politicians? Keep speaking out - but louder!!! Thanks, Donald Patriquin
Tim Loncarich Comment left 24th August 2009 18:06:42
Since most deforestation is done to grow grain to feed to animals which are fed to humans wouldn't it make sense to switch to a healthier plant-based diet and reforest the land no longer needed? Since humans don't require meat in their diet to be healthy, adopting a vegan diet is one quick and easy solution anyone can put into action. It costs nothing and the benefits are immediate.
Ken Griffith Comment left 26th August 2009 07:07:07
The suggestion that faster growing plants lock up oxygen from the atmosphere is amazingly ignorant. In photosynthesis water molecules, H2O, are split, the hydrogen is joined to the CO2 from the air and the excess O2 is released. This increases O2 in the air. In respiration, the Oxygen is rejoined with hydrogen, forming water. Therefore increase in plant biomass locks up hydrogen derived from WATER, and increases atmospheric O2. Plants take up water not O2! "In the process, it could precipitate an oxygen crisis from which we would never recover." Before making such wild claims, one should measure the amount of hydrocarbons in the biosphere and compare it to the amount of oxygen in the atmosphere. If 100% of the world's biomass were to be oxidized in one second, it would use less than 1% of the oxygen from the atmosphere, because there isn't very much biomass compared to Oxygen. Some more realistic oxygen sinks would be: A. Release of un-oxidized iron from the earth and groundwater, oxidizes on contact with air and locks up oxygen in the form of rust. B. A pathway where O2 -> respired with fossil fuel -> C02 -> CO2 dissolves in Seawater and precipitates as CaCO3. Now this is a pathway where Oxygen in the air gets locked up as limestone through biological means. So a more realistic correlation to look for would be precipitation rates of CaCO3 in seawater. Whoever wrote this article proves that academic degrees are not worth the paper they are printed on!
Ken Griffith Comment left 26th August 2009 07:07:34
Correction to my last comment: The pathway of CO2 dissolving in seawater and precipitating as CaCO3 does not convert any O2 from the air into CO2. However, the respiration side of that reaction, which combines O2 with the hydrogen in the starchy plant fuel, produces water vapor. Therefore this pathway leads to conversion of atmospheric oxygen to water. If the carbon dioxide is locked up in limestone or other deep storage, then there has been a net loss of atmospheric oxygen converted to water. The only way to reverse this process is to introduce new carbon into the atmosphere as CO2 to enable photosynthesis. This new carbon comes from surface erosion of limestone and fossil fuel bearing rocks. Some think burning Coal reduces O2 because it is 95% Carbon. This is true. However, at some time in the past coal was biomass, so the oxygen was released when the coal was formed. This oxygen has usually combined with other elements such as sulfur so that when mining coal carbon monoxide and sulfur dioxide must be vented from the mine. Therefore when coal is returned to the biosphere through mining or through natural erosion, the oxygen that was originally in the plant material has also been re-introduced to the atmosphere. This is also true of natural gas, where methane is usually found with sulfur dioxide and carbon monoxide gas. Carbon dioxide is the "substrate" on which photosynthesis and respiration occur, splitting water in photosynthesis and recombining it in respiration. Therefore to reduce oxygen in the atmosphere all you have to do is to steadily remove carbon dioxide - not because of the O2 in carbon dioxide, but because of the O2 that is now locked up as H2O. Clearly, there is not enough carbon dioxide in the atmosphere to produce a major effect. Plant life would starve of CO2 before the oxygen concentration of the atmosphere declined by even 0.5%. However, the natural release of iron from the earth, forming iron oxide, is a process that is only reversible by mankind (producing iron from ore), and possibly by biological activity. Therefore, iron released from groundwater, and calcium carbonate precipitation in seawater, are the most likely causes of the small oxygen decrease you speak of here. However, the human production of metal from ore reverses the process. So the question is whether the production of metal releases oxygen in an amount similar to the amount being locked up by the two oxygen sinks listed above. The idea that rapidly growing plant-mass locks up oxygen is completely wrong. I would be very embarrassed if I had published a paper like this.
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