Addenda

1: Is there an Increase in Marine Photosynthesis to Compensate for the Decline in Terrerstrial Photosynthesis?

Some anti-green commentators believe that over the last few decades there has been an increase in terrestrial Photosynthesis. Others fear that oomans' decimation of Forests has led to a decrease in terrestrial Photosynthesis but believe that this is not significant because the nutrients will end up in the oceans stimulating marine Photosynthesis. This section explores the possibilities of marine Photosynthesis making up for the destruction of terrestrial Photosynthesis.

1.1: Phytomass on Land and in the Oceans.

There is less Phytomass in the oceans than there is on land.

1.2: The Photosynthetic Productivity of Land and Oceans.

Although there is less Phytomass in the oceans than on land, the Photosynthetic productivity of marine Plants is far greater than that of terrestrial Plants, “Plant biomass may be 10,000 or more grams of dry matter per square metre in a Forest, in contrast to 5 grams or less in the open water of ponds, lakes and oceans. Despite this biomass discrepancy, 5 grams of Phytoplankton are capable of manufacturing as much food in a given amount of time as are 10,000 grams of large plants, given the same input of light energy and nutrients. This is because the rate of metabolism of small organisms is much greater per unit weight than that of large organisms. Furthermore, large land Plants such as Trees are composed mostly of woody tissues that are relatively Photosynthetically inactive; only the leaves Photosynthesize, and in a Forest, leaves comprise only 1 to 5 percent of the total plant biomass.”[1]

1.3: The Quantity of Photosynthesis Carried out by Forests and Oceans.

Given that marine Phytomass is less pervasive but more productive than terrestrial Phytomass, the question which arises is whether the oceans carry out more Photosynthesis than Forests. Determining this answer would help to solve the question as whether it is the oceans or Forests which are absorbing the Carbon dumped into the atmosphere as a result of industrial development. This is one of the most contentious issues concerning the anthropogenic boost to global warming .[2]

In the 1940s it was commonly assumed there was more Photosynthesis in the oceans than on the land. However, some commentators at the time believed the opposite, "Commonly quoted values are 190 x 10¹⁰ GJ primary production on land with another 110 x 10¹⁰ in the seas, whereas the world's energy use is around 15 x 10¹⁰ GJ/yr."[3]

In the late 1950s roger revelle’s work on the relationship between Photosynthesis in the oceans and on the land became influential. He made several points. Firstly, that oceanic absorption of anthropogenic Carbon emissions was limited. He .. “disproved an idea, popular among conservatives, that the oceans through their mass could absorb almost any human output of CO₂..”[4] This had enormous implications for ooman pollutants.

Secondly, he argued the oceans absorbed only half of anthropogenic emissions, “In 1957 .. Roger revelle and hans suess, working at the scripps institute of oceanography in san diego .. found that the oceans absorb only 50% of the excess Carbon dioxide produced by man.”[5]; “Revelle showed that ocean absorption of human-generated carbon dioxide appears limited to about the level of the world economy exceeded early in the postwar era.”[6]

Finally, he proposed the idea of a missing Carbon sink because it was not possible to determine which Photosynthesizers were absorbing a significant proportion of anthropogenic emissions, “When in 1958 revelle produced the first precise atmospheric CO₂ data, he was immediately struck by something: Half of artificial production was missing. Seven or eight billion tons of carbon dioxide are put into the air each year by human action, but when researchers test the atmosphere, only about 3 billion tons read as present. Where does the missing Carbon go? This missing-carbon problem has haunted greenhouse science ever since.”[7]

Subsequent research further diminished the role of the oceans in absorbing atmospheric Carbon, "Although an estimated 41% of Photosynthetic activity takes place in the oceans, it is the 59% occurring on land that underpins the world economy."[8] In the early 1990s some researchers suggested the oceans have only a minor role in extracting Carbon from the atmosphere, "The oceans are soaking up considerably less CO₂ than researchers previously thought. We are saying it is probably less than 1 Gt each year."[9]

In the mid-1990s tyler volk suggested that terrestrial Photosynthesis is greater than marine Photosynthesis, “Global photosynthesis currently uses 60 billion tons of carbon on land and 40 billion tons in the ocean each year, for a total of 100 billion tons of carbon.”[10] He cited the work of the mauna loa scientists measuring the concentration of atmospheric Carbon since the late 1950s. They have produced a famous graph showing rising concentrations of atmospheric Carbon. However, within this overall trend it can be seen that each year there is a regular increase, and then a decrease, in the concentrations of atmospheric Carbon. In the first half of the year there is a huge increase in the release of Carbon as a result of industrial emissions and Phytomass respiration. In the second half of the year there is a slightly smaller decrease in the concentration of atmsopehric Carbon as a result of Photosynthesis. The increase in the concentration of atmospheric Carbon has always been greater than the decrease resulting in a rising trend over the last forty years. Bunyard agrees with volk that, “Photosynthesis on land captures sixty billion tonnes of the total carbon and the oceans the remaining forty billion tonnes.”[11]

Volk points out that this annual cycle of Photosynthesis and respiration becomes increasing pronounced in northern latitudes, “The further poleward one treks, the more the gases (from Photosynthesis and respiration) pulse with the thermal seasons.”[12]; “The higher the latitude in the northern hemisphere, the more extreme the seasonality of photosynthesis and respiration, the more vigorous the amplitude of the CO₂ cycle.”[13] He believes this shows that the oceans are not absorbing large amounts of atmospheric Carbon.

These prevailing views began to change in the late 1990s. An increasing number of commentators began to promote the idea that the oceans absorb more Carbon than Forests, “The marine algae .. releasing no less than 70% of the world’s atmospheric oxygen.”[14] John houghton estimates that of the 7.5Gt of Carbon released into the atmosphere each year, half stays in the atmosphere and that, “If 2Gt of the rest ends up in the oceans there remains an imbalance of about 1.7Gt or so to be accounted for.”[15] The evidence for the conclusion that the oceans absorb more Carbon than the land derives from a study of Carbon isotopes. There are three isotopes of Carbon. In the atmosphere they exist in the following proportions:-

¹²C - 98.9%;

¹³C - 1.1%;

¹⁴C - present in only very small amounts.

Houghton argues, “When Carbon dioxide is taken up by plants and other living things, less ¹³C is taken up in proportion than ¹²C. Fossil fuel such as coal and oil was originally living matter so also contains less ¹³C (by about 18 parts per thousand) than the Carbon dioxide in ordinary air in the atmosphere today. Adding Carbon to the atmosphere from burning Forests, decaying vegetation or fossil fuel will therefore tend to reduce the proportion of ¹³C. (All the ¹⁴C in fossil fuels has decayed). As Carbon from fossil fuels is added to the atmosphere the proportion of ¹⁴C in the atmosphere is also reduced. By studying the ratio of the different isotopes of Carbon in the atmosphere, in the oceans, in gas trapped in ice cores and in Tree rings, it is possible to find out where the additional Carbon dioxide in the atmosphere has come from and also what amount has been transferred to the ocean.”[16]

Greenpeace supports this evidence, “Around twice as much Carbon is emitted by fossil fuel burning and deforestation as ends up in the atmosphere. Some 7 billion tonnes of Carbon comes from fossil fuel and forest-burning, and we know that only 3.4 billion tonnes of Carbon stays up in the atmosphere as Carbon dioxide each year. How much of the rest goes into the land-plant sink, and how much goes into the ocean sink, has in detail always been a mystery. A new estimate for Carbon uptake suggests 2.1 billion tonnes of Carbon goes into the oceans, with a billion tonnes of Carbon going into the land sink. This new estimate differs with earlier studies which estimated that only a billion tonnes of Carbon are being taken up by the oceans, with more than two going into land plants. This new study uses Carbon isotopes. Both fossil fuels and plants are lighter in Carbon-13 than atmospheric Carbon dioxide, so that the decrease in Carbon-13 over time in ocean waters gives a measure of how much anthropogenic Carbon dioxide is being taken up by ocean waters.”[17]

Greenpeace highlights another piece of evidence suggesting the oceans are a more important Carbon sink than Forests. The rise in the level of atmospheric Carbon dioxide in 1992 was smaller than usual as a result of the mount Pinatubo eruption the previous year, “1992 was in fact the largest anomaly record from the mauna loa (hawaii) monitoring station in 35 years of data. Reductions in fossil-fuel burning are clearly not the reason. So where did the Carbon go? It seems that the pinatubo eruption may well have played a role. Important clues come from Carbon isotopes in the gas. Photosynthesis takes up the lighter isotope preferentially, and so tends to force the ratio of the heavier-to-lighter isotope up. Ocean uptake, however, has an insignificant effect on the ratio. The fact that the ¹³C/¹²C ratio does not show any anomaly, therefore, indicates that the ocean was responsible for the additional uptake of Carbon dioxide. One possible explanation is that the fallout from the eruption of mount pinatubo in 1991 caused a rapid fertilization of the oceans, leading to a bloom in Phytoplankton. Pinatubo erupted material containing some 500 million tons of iron, whereas fixation by Phytoplankton of the 4 billion tonnes of Carbon estimated to have been “withdrawn” from the atmosphere between may 1991 and the end of 1992 would require only a fraction of a million tonnes ...”[18]

1.4: Those who believe Marine Photosynthesis is bigger than Terrestrial Photosynthesis.

It should be pointed out, however, that when some commentators talk about the oceans extracting Carbon from the atmosphere they do not mean this is done entirely by Photosynthesis. A significant proportion is removed by the oceanic conveyor belt, “Each year the oceans dissolve up to 2 billion tonnes of CO₂ from the atmosphere. The oceans ‘bury’ CO₂ by removing it from the surface layers of water. One key way of doing this is through convection currents, the biggest of which is the ‘conveyor belt’ that begins in the north atlantic. As ice forms here, saltier - and therefore denser - water is left behind. This denser water falls to the ocean floor, drawing water in behind it and setting up a current that begins a 1000 year journey around the world. When it returns to the north atlantic, it contains less CO₂.”[19]

Gribbin, John.

John gribbin implies the amount of atmospheric Carbon being absorbed by the world’s oceans could be even larger than that suggested above, "The existence of the surface layer, a layer just 1 millimetre thick, is generally as much as 0.3C cooler than the bulk of the water in the upper layer of the ocean. Standard models which take no account of the influence of this cool layer suggest that the uptake of Carbon from the air by the oceans is about 2.2 GtC per year. By allowing for the effect of the 'cool skin' .. there will be an additional global uptake of CO₂ equivalent to about 0.7 GtC per year."[20]

Brown, Paul.

Paul brown believes that, “At the moment it is calculated that the oceans remove about 3 billion tonnes more Carbon dioxide a year than they put back into the atmosphere.”[21]

World Wide Fund for Nature.

“Scientists have not yet balanced the modern carbon cycle. They know that some 5.5 billion tonnes of CO2 (measured as Carbon) are released by fossil fuel burning and other industrial emissions. To this they add an estimated 1.6 billion tonnes from deforestation and other land use changes in the tropics. Of this total of 7.1 billion tonnes, some 3.3 billion tonnes remain in the atmosphere, and an estimated 2 billion tonnes are absorbed by the oceans. That leaves 1.8 billion tonnes. Though there remain considerable uncertainty, much of this currently appears to be absorbed by non-tropical forests in the northern hemisphere, through a mixture of new forest growth and possibly the fertilisation effect.”[22]

1.5: The Declining Productivity of the Oceans.

The most recent contribution to this issue was made by gaians who pointed out that oceanic productivity is declining in comparison to that of terrestrial Photosynthesis. They argue that as the oceans warm up there is an increase in oceanic stratification which prevents nutrients from rising from the sea floor to feed on Phytoplankton at the surface of the sea .. “the contribution from land to the stabilizing of global temperatures is from vegetation drawing down Carbon dioxide. As temperatures increase, so Plants suffer from drying out of soils and from water stress. Their efficiency in taking Carbon dioxide out of the atmosphere is thereby significantly reduced. Kump and lovelock conclude that ocean warming is now proceeding rapidly, especially in the tropics and lower latitudes, with the result that Plankton activity is declining. The oceans are therefore losing their ability to regulate the climate. Terrestrial vegetation will lose its ability to regulate the climate once the average surface temperature reaches around 18C - ipcc estimates that a century from now, the Earth will have temperatures close to that critical point.”[23]

1.6: Oomans’ Disturbance of the Forest-Ocean Relationship.

The scientific evidence concerning the uptake of Carbon by land and oceans is poor and has yet to be resolved. However, it would not be surprising if it was discovered that the oceans are currently carrying out more Photosynthesis than Forests because this could well be the consequences of ooman activities. Firstly, oomans are decimating the Earth’s Forests. Oomans have cut down nearly a third of the Earth’s Forests since the end of the ice age, a significant proportion of which has taken place since the end of the last world war. It is hardly surprising the current level of Photosynthesis carried out by Forests is not as great as it was in the past.

Whilst oomans are dramatically reducing Forests’ Photosynthetic capabilities, they are also dramatically increasing the amount of nutrients being dumped into the oceans. This is happening because of a number of factors. Firstly, the dumping of vast quantities of ooman and livestock manure into watercourses leading into the world’s oceans. Secondly, deforestation is causing soil erosion and vast quantities of soil are being washed into rivers and then into the oceans. Thirdly, what soil is left on the land after deforestation is often blown into the air causing huge dust storms providing even more nutrients for the oceans. Finally, the razing of Forests releases nutrients into the atmosphere some of which also end up in the oceans.

1.7: The Political Implications of the Forest-Ocean Controversy.

The debate as to whether the world’s Forests carry out more Photosynthesis than the oceans is by no means solely an academic dispute. It has serious political implications. Firstly, those who believe the oceans absorb most atmospheric Carbon tend to argue that anthropogenic Carbon emissions are not a serious problem. They suggest the greenhouse effect poses no barrier to fullscale economic development because even if huge amounts of Carbon are dumped into the atmosphere they will be soaked up by the oceans. Secondly, even worse, is the argument that oomans can continue cutting down Forests because the loss of terrestrial Photosynthesis poses no threat to the greenhouse effect since, once again, the oceans will take up the Photosynthetic slack. It is believed that as Photosynthesis declines in Forests, the nutrients will invariably be transported to the oceans boosting marine Photosynthesis. This is often true - but not always. But, even when it is true, it takes time for the nutrients to travel from the land to the sea and then to disperse along the sea floor. In addition, some nutrients end up boosting Algal growth which destroys other marine Phytomass

The commentators who give primacy to marine Photosynthesis have a means of escaping blame if they are eventually shown to be wrong. They argue that even if it is discovered they are wrong about the superiority of oceanic Photosynthesis over terrestrial Photosynthesis, which would thus boost global warming, it doesn’t matter because it should be possible for oomans to counter rising temperatures by seeding the world’s oceans with nutrients. They argue this would stimulate Photosynthesis and extract huge amounts of Carbon from the atmosphere. This is a rather bizarre argument given that, over the last fifty years or so, oomans have been overstimulating oceanic Photosynthesis by dumping vast quantities of ooman and Animal manure into the oceans creating vast blooms of toxic algae.

Another political implication is that the commentators who believe in the superiority of oceanic Photosynthesis dismiss the idea of Reforestation as a means of combatting the greenhouse effect. However, it should be pointed out that even if it was shown that the oceans are currently carrying out more Photosynthesis than Forests, there are a number of reasons why this would not necessarily undermine the importance of Reforestation in combatting global burning. Firstly, Forests are a major determinant of the level of Photosynthesis in the world’s oceans. Secondly, as has already been noted above, oomans have disturbed the relationship between oceans and Forests to such an extent that it only appears to be the case that oceans are more Photosynthetically productive than Forests. Finally, the major impact which Forests have on global burning is not through the Earth's Carbon spiral but through the water cycle and the albedo effect. Dismissing Reforestation as a means of combatting global burning just because its impact on the Carbon spiral is currently secondary to that of the oceans could be a mistake.

1.8: Damage to Oceanic Photosynthesis.

The oceans' capacity to absorb CO2 is being reduced by pollution; the thinning of the stratospheric ozone layer; and an increase in ocean stratification reducing the nutrients reaching plankton's on the surface of the oceans. Like so much else to do with the oceans it is not certain what the net effect of these various factors will be on the oceans' ability to absorb CO2. Despite the vast size of the oceans they are unable to absorb all the carbon currently being dumped into the atmosphere. The increasing level of atmospheric Carbon seems to imply the oceans have passed the point where they can offer a natural solution to ooman pollution.

2: The Destruction of Wildlife is an Indication of the Reduction in Global Photosynthesis.

Wildlife does not play a direct role in extracting Carbon from the atmosphere. However, it does have an important role in storing Carbon. An old-growth Forest stores far more Carbon than a Tree plantation because it is inhabited by vast numbers and varieties of Animals. Over the course of time, new species emerge which survive by exploiting unused ecological niches. In turn, these new species creates new niches for other species. Biodiversification is the process by which more and more Animals create more and more ecological niches which enable more and more Animal species to survive and develop. It is a process, like russian dolls, which packs more and more species into a particular habitat - especially those as palatial as Forests. As a consequence, the greater the concentration of Animals in a habitat, the more Carbon which ends up in the ground, creating even more Soil, enabling more Trees to flourish, creating more habitats to be exploited. Biodiversification has the effect of packing more and more Carbon under the Forest canopy.[24] If there was no Biodiversity the amount of Carbon that could be stored in Forests would be far smaller.