Hot coal and photosynthesis – one answer – the Island


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I wish GADS had stuck to its hesitation, without displaying its ignorance of basic chemistry and global gas cycles to defend its precious fossil fuels. Let me clarify:

Carbon (C), the fourth most abundant element in the Universe, after hydrogen (H), helium (He) and oxygen (O), is the cornerstone of life. It is the basic building block that anchors all organic substances, from fossil fuels to DNA. On Earth, carbon travels through the earth, the ocean, the atmosphere and the interior of the Earth in a major biogeochemical cycle (the movement of chemical components through the biosphere from or to the lithosphere, atmosphere and hydrosphere).

The global carbon cycle can be divided into two categories: the geological / ancient cycle, which operates on large time scales (millions of years), and the biological / modern cycle, which operates on shorter time scales ( days to thousands of years).

The global carbon stock

The global carbon store began billions of years ago, when planetesimals (small bodies formed from the solar nebula) and meteorites containing carbon bombarded our planet’s surface, steadily increasing the carbon content. of the planet. Today, these increases in the planet’s carbon stock have stopped, but the stock has become more compartmentalized.

Since that time, carbonic acid (a weak acid resulting from the reaction between atmospheric carbon dioxide [CO2] and water) has slowly but continuously combined with calcium and magnesium in the earth’s crust, to form insoluble carbonates (chemical compounds containing carbon) through a process called weathering. Then, through the process of erosion, the carbonates are carried into the ocean and eventually settle to the bottom. The cycle continues as these materials are attracted into the Earth’s mantle by subduction (a process in which one lithospheric plate descends under another, often as a result of mantle bending or faulting) to the edges of the continental plates. . The carbon is then returned to the atmosphere as carbon dioxide during volcanic eruptions.

The balance between weathering, subduction, and volcanism controls atmospheric concentrations of carbon dioxide over periods of several hundred million years. The oldest geological sediments suggest that before the evolution of life, the concentration of atmospheric carbon dioxide could have been a hundred times that of today, creating a very different atmosphere and a substantial greenhouse effect.

Fossil carbon

The workings of life have been clearly shown to change the chemistry of this atmosphere to what it is today. One of the most active agents of this change was ocean plankton, a microscopic photosynthetic phytoplankton that produces prodigious amounts of oxygen and biomass over time. Oxygen is released into the atmosphere and the biomass is consumed by the respiration of zooplankton (microscopic marine animals) within days or weeks. Only small amounts of residual carbon from this plankton are deposited on the ocean floor at any given time, but over long periods of time this process represents a significant removal of carbon from the atmosphere. This slow removal of carbon from the primary atmosphere to the fossil reservoir, while at the same time creating an atmospheric reservoir of oxygen, had a major effect on the maintenance of biotic homeostasis.

A similar process repeated itself on the earth, especially during the Devonian era, the enormous mass of vegetation that covered the earth absorbing carbon dioxide and then was mineralized in the lithosphere to coal, effectively removing this volume of carbon dioxide. carbon in the earth’s atmosphere. The oxygen released by these first prodigious forests greatly contributed to the current chemistry of the atmosphere.

Thanks to this process, still active today, the carbon that enters the lithosphere is completely removed from the biological cycle and mineralizes in cycles with ages of hundreds of millions of years.

The modern carbon cycle

On earth, the main carbon exchanges with the atmosphere result from photosynthesis and respiration. During the day of the growing season, the leaves absorb sunlight and absorb carbon dioxide from the atmosphere. In the oceans, the planktonic cycle operates a similar photosynthetic cycle. Both create biomass. At the same time, plants, animals and microbes in the substrate consume this carbon as organic matter and return carbon dioxide to the atmosphere. When conditions are too cold or too dry, photosynthesis and respiration cease as well as the movement of carbon between the atmosphere and the earth’s surface. The amounts of carbon that move from the atmosphere through photosynthesis, respiration, and return to the atmosphere are large and produce oscillations in atmospheric concentrations of carbon dioxide. Over the course of a year, these biological carbon fluxes are more than ten times greater than the amount of carbon introduced into the atmosphere by the combustion of fossil fuels. However, fluxing carbon was part of the biosphere, and the carbon circulating in the biosphere had a very significant chemical signature of carbon isotopes, the ratio of 13C to 12C. This flow of biotic carbon occurs in cycles of a few days to thousands of years, but maintains the same isotope ratio. It also maintains a quantity of the rare unstable isotope 14C. Any carbon that lacks 14C or has a lower 13C / 12C ratio does not belong to the modern or biotic cycle.

Today, kidnapping seems to have taken on the meaning of an “act of kidnapping” more than of a “product of kidnapping”. Most models of carbon sequestration look at growing plantations as opposed to maintaining established forest stocks. The equation is simple and straightforward; the carbon that is immobilized in the biological cycles of the planet has value as sequestered carbon. The time horizon for which carbon can be sequestered contributes to the value of this stock. So that if the carbon fixed by a Wheat Field has a value because it sequesters carbon, this value is low because it can only sequester it for a time horizon of less than one year. In contrast, a forest or peatland represents a carbon stock that has time horizons of hundreds or thousands of years and has much higher sequestration values. However, there is no biological process that can sequester carbon for periods greater than 100 million years, except by fossilization.

So. the gist is this: “No matter what, there is no scientifically valid technology that can block fossil carbon for millions of years using biological processes. Using carbon dioxide in photosynthesis to justify burning coal is cheating, as noted above.

Please stop defending fossil fuels, they are biospheric toxins that will poison the planet and ruin our children’s future!

RANIL SENANAYAKE

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About Lucille Thompson

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