The Geosphere and Hydrosphere: Roles in Global Warming
written by: Envirowords•edited by: Sarah Malburg•updated: 1/9/2010
Global warming may be happening; but to truly understand the impact of carbon dioxide and other greenhouse gases, it is necessary to understand the carbon cycle which is the movement of carbon between the geosphere (earth's interior), the hydrosphere (earth's water) and the atmosphere (earth's air).
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The Carbon Cycle through the Geosphere
The carbon cycle is the movement of carbon. We inhabit a carbon based planet. Carbon is an essential component of photosynthesis, the process by which plants use solar light and carbon dioxide to produce oxygen. In the solar system, the planet Earth is special because our atmosphere contains oxygen, necessary for life, making Earth the only planet within the cosmos that sustains life. The Earth's atmosphere is 20% oxygen and 78% nitrogen; the remaining 2% consists of various other gases. Carbon dioxide makes up 0.033% of the total volume of air.
The Earth's unique geology and hydrology provides the structure, like a wheel, by which carbon cycles. Carbon moves unencumbered through the cycle. Carbon dioxide is pulled from the atmosphere to create oxygen through photosynthesis on large scales, for example, through big forests and on a small scale, for example, through phytoplankton which are tiny aquatic plants. Carbon is released into the atmosphere when fossil fuels are burned and through respiration, we take in oxygen and release carbon dioxide through out lungs.
Carbon dioxide is everywhere in minerals, air and water. The carbon cycle is quite complex but can be simplified and used to understand all the impacts of global warming, even the beneficial ones.
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Carbon dioxide is a gas but carbon can also be found in solid form (coal) and liquid form (oil). Carbon based fuels are fossils extracted from the Earth's interior. The minerals, rocks and land formations below and on the Earth's surface are called the geosphere. These fossilized deposits were created millions of years ago when plants and animals died and were compacted and preserved by geologic processes. Coal, oil and natural gas are the product of these geological processes and when we burn these fuels to create electricity or heat we release the chemicals like carbon dioxide and methane into the atmosphere, both of which are greenhouse gases.
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Water plants, like algae and phytoplankton absorb carbon dioxide. The carbon dioxide is originally absorbed into the water column and aquatic plants draw the carbon dioxide from the water. In fact, 70% of the Earth's surface is covered with water and is called the hydrosphere. The oceans, seas, lakes, ponds, rivers and streams are huge carbon sinks, meaning carbon sinks into them and is stored for a long period of time. Ocean acidification occurs when too much carbon is absorbed into the water column making oceans acidic which decreases ecosystem sustainability. Coral reefs are being destroyed because the acidic water inhibits the production of calcium necessary for coral development.
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Carbon sinks can be naturally occurring, for example, oceans and forests, or man-made, like carbon sequestration projects that mechanically trap emissions from utility plants and pump them deep into the subterranean geosphere to be contained for long periods of time. Whether man made or naturally occurring, carbon sinks are necessary to remove carbon dioxide from the atmosphere to inhibit global warming.
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Global warming is the increase in average global temperatures as a result of excess gas emissions that cannot be adequately processed by the Earth. The excess emissions clog up the carbon cycle and trap heat within the Earth's lower atmosphere increasing surface and water temperatures. Predictions have been made that increased global temperatures will result in migrating ecosystems and more frequent and intense catastrophic weather events. In plain English, land farther away from the equator will become more suitable for growing crops, land closer to the equator will become drier and less hospitable for large populations; hurricanes and tornadoes will become more frequent and cause more damage.
However, things are not as dire as current propaganda presents. In biology there is a concept of homeostasis which is the ability of a cell to maintain equilibrium by adjusting physiological processes accordingly. Perhaps, this concept can be extrapolated to the Earth's ability to absorb carbon. Climate change models are beginning to incorporate assumptions about how increased gas emissions will produce more clouds that will counteract global warming through cooling. Remember the ocean acidification problem described above, a benefit of increased water carbon is increased plankton and algae production, both plants thrive with increased carbon dioxide. These plants are a main food source for larger fish which will increase fish abundance.
The carbon cycle connects the atmosphere, hydrosphere and geosphere. Releasing carbon from the geosphere at excessive rates and volumes may be altering the atmosphere and hydrosphere, however, the Earth may be counteracting global warming through homeostasis. Understanding the carbon cycle will enable us to prepare for positive and negative impacts.