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Weathering, the carbon cycle and the global climate



By: Edgar Mana-ay

There is much discussion about carbon dioxide or CO2 as a "greenhouse gas" (GHG) in the atmosphere that traps the radiant heat of the earth and causes global warming. As a component of CO2, the basic element carbon is subject to a natural process, the so-called inorganic carbon cycle, which is triggered by the weathering process. It is not just rocks, but all elements are affected by the weathering process.

Basically Weathering refers to the process that over time alters the physical and chemical nature of rocks and other elements. For example, if you leave a car in open space for a long time, especially in the tropics, where rain and sunlight are abundant, the paint will flake off and the metal will rust.

The carbon cycle begins when CO2 is released into the atmosphere through decaying organic matter such as trees, electric power plants, cars, and through volcanic eruptions, as in the case of the volcanic eruptions in Hawaii. Kilauea. The highly dispersed in the atmosphere CO2 dissolves in water vapor and forms carbonic acid (H2CO3) in the atmosphere. This natural, weak acid, which is now in liquid form, will fall as part of the rain. Carbonic acid as part of the rain reacts with sediments and rocks during chemical weathering (alteration of rocks and mineral deposits on the earth's surface due to the reaction between the earth's materials and atmospheric constituents such as water, oxygen and carbon dioxide). Calcium and bicarbonate ions (HCO3 ̵

1; ) are released, which are transported by rivers into the sea.

The precipitation of CaCO3 mineral (which began as CO2 in the atmosphere) forms layers of limestone cliffs. The deep burial of limestone leads to Metamorphosis (the transformation of already existing rock into a new rock due to texture or mineralogical conditions due to high temperature and pressure deep underground, but without melting process). As a result, silica and calcite form calcium silicate minerals and carbon dioxide .

The CO2 remains trapped inside the Earth until it is released by a volcanic eruption to complete the cycle for the return of CO2 to the air. Of the CO2 in the atmosphere passing through this carbon cycle, less than 5% are returned to the atmosphere by volcanic eruption, and the 95% remain hidden underground as limestone or are transformed into metamorphic rocks such as marble. You see that nature has its own way of storing carbon dioxide from the atmosphere and burying it deep underground!

A comparison of the percentage of CO2 in the atmosphere: Earth – 0.33%; Mars – 95.3% and Venus – 96.5%. Earth has just enough CO2 in its atmosphere to keep most of the surface above freezing, but not too hot to support life. But when the Earth first formed, its atmosphere was probably very similar to that of Venus. What happened to most of the original carbon dioxide in the Earth's atmosphere? Geologists believe that a quantity of CO2 equivalent to about 65,000 times the mass of CO2 in the current atmosphere is hidden in the crust and upper mantle.

Part of this CO2 was used for organic molecules during photosynthesis and is now included as buried organic matter and fossil fuels in sedimentary rocks. (Think of millions of years and the formation of coal and oil). However, most of the missing CO2 was converted to bicarbonate ions (HCO3 ) during chemical weathering and included in carbonate materials.

The inorganic carbon cycle discussed above helps to regulate Earth's climate because CO2 is a greenhouse gas, accelerates chemical weathering with warming, and the formation of limestone occurs mainly in warm, tropical oceans. When the Earth's climate is warm, chemical weathering and limestone formation increase, removing CO2 from the atmosphere, which cools the climate. As the global climate cools, chemical weathering and limestone formation slows, allowing CO2 to accumulate in the atmosphere that warms the earth.

An increase in chemical weathering can also lead to global cooling by removing more CO2 from the atmosphere. For example, the Cenozoic (65 million years ago, when the dinosaurs were extinct) triggered the elevation and weathering of high mountains such as the Alps and the Himalayas, causing global cooling that culminated in icing (a large mass of ice formed ashore , which moves under its own weight, which deeply and distinctly changes the Pleistocene (1.6 million years ago) earth landscape.

Man is really just a tiny speck on Earth and its atmosphere, that they really have the CO2 The Earth is 4.5 billion years old, but the first sign of life did not appear until about 500 million years ago in the form of trilobites that had crawled on the muddy bottom of the sea, the oldest fossil found with eyes Hominids (modern humans and our extinct ancestors) have a fossil record of 6 million years, in all these times ha Nature or God has already provided the mechanism and guarantees that His earth is habitable to the later modern man and all the other creatures he has created.

While we humans can not change the atmosphere, we remain We have a great responsibility to care for our immediate environment as we were at the beginning. For the Holy Scripture in Revelation 7: 3 said, " Do not hurt the earth, neither the sea nor the trees."

Note: The Author is the Pavia Hydrogeology Advisor and a Professional Member of the US National Ground Water Association (NGWA)


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