Earth as a closed system
Earth as a closed system means that mass is not allowed to be transferred in and out of Earth's system but it allows energy to move in and out of Earth's system. To define Earth as a closed system, we need to understand the Earth’s System and thermodynamic systems.
There are five main systems, or spheres, on Earth.
The first system, the geosphere, consists of the interior and surface of Earth, both of which are made up of rocks.
The second system supports living things and life on Earth.
The third system comprises of enormous amounts of water on Earth.
The fourth system, which consists of an envelope of gases that keeps the planet warm and provides oxygen for breathing and carbon dioxide for photosynthesis.
The troposphere is the lowest layer of the atmosphere, extending from the Earth's surface up to an altitude of about 7 to 20 kilometers (4 to 12 miles) depending on the location. It contains about 80% of the atmosphere's mass and is where all weather occurs. The temperature in the troposphere generally decreases with altitude, which is why it's often called the "lower atmosphere."
The stratosphere is the layer of the atmosphere that lies directly above the troposphere, extending from about 20 to 50 kilometers (12 to 31 miles) above the Earth's surface. The stratosphere contains the ozone layer, which absorbs harmful ultraviolet radiation from the sun. The temperature in the stratosphere generally increases with altitude, which is why it's often called the "upper atmosphere."
The fifth system, which contains huge quantities of ice at the poles and glaciers etc.
Earth’s systems are interconnected in a complex way that changes in one lead to change in the other systems.
A thermodynamic system is a part of the physical universe with a specified boundary for observation.
1. In a closed system, material content is fixed and internal overall composition changes only due to a chemical reaction. Closed systems exchange energy only in the form of heat or work with their surroundings. It allows transfer of energy but not mass.
2. In an open system, material and energy content are variable, and the systems freely exchange mass and energy with their surroundings.
3. Isolated systems cannot exchange energy and matter.
Implications to the environment
Earth as a closed system means that mass cannot be transferred in and out of earth's system because of presence of gravitational forces but energy is allowed to move in and out. For example, the cryosphere may melt and refreeze, but no new water is added to it or to the hydrosphere. The water that evaporates goes into the air and then precipitates and falls back and the cycle continues. These processes are indicative that total mass of earth’s system in geosphere, biosphere, hydrosphere, and cryosphere remains constant. Only the atmosphere in earth’s system is an exception where it can exchange energy from its surroundings. For example, earth allows sunlight to enter the atmosphere which is a form of energy. Energy radiates into the Earth’s system, mainly from the sun. Energy is then radiated back into space from the Earth, with the flows being regulated by the Earth’s atmosphere and ozone layer. This balanced transfer of energy maintains the surface temperature at a level which supports the existence of life on Earth. Physicists and astronomers claim that the Earths’ atmosphere also interacts with its surrounding by solar winds, electromagnetic radiations and magnetic storms.
The implications of Earth being a closed system constitutes solving complex ecological challenges. It includes managing availability of carbon dioxide and oxygen at faster cycling rates depending on seasonal variations. Due to the increase in human population, loss of biodiversity and use of wild ecosystem for human use by soil erosion and use of non-renewable natural resources have created an imbalance in the earth’s system.The critical aspect of achieving sustainability in a closed system is to prevent the increase in greenhouse gases in the atmosphere which is shrinking the ozone layer and results in climate change and global warming.
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