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Greenhouse effect

Greenhouse effect

The greenhouse effect is the process by which the atmosphere of a planet passes solar radiation from the Sun, but instead prevents or hinders the thermal energy output of the planet.

It is called greenhouse effect due to the similarity with the operation of the greenhouses that are able to retain the heat inside. The operation is not exactly the same, but it is very similar. The difference is that the greenhouse uses the glass and not the gases in the atmosphere to retain heat. That is why this natural phenomenon has been called the greenhouse effect.

When we talk about the greenhouse effect we almost always refer to the greenhouse effect on planet Earth, but it also occurs in a similar way to other planets like Venus and Mars.

Operation of the greenhouse effect

At the moment when the solar radiation that reaches the Earth's atmosphere part of this radiation is reflected while another part is absorbed and enters the atmosphere. Most of the radiation that has managed to enter the atmosphere reaches the earth's surface. This causes the surface to heat up, and some of this heat to be transferred in the form of radiation, but at wavelengths greater than that of the original solar radiation.

From the infrared radiation that sends the Earth's surface, only an important part (approximately 90%) will get back through the atmosphere and will go out into space. The rest of the radiation heats the gases of the atmosphere and its heat energy stays there, so the planet is surrounded by a set of hot gases that help to heat it. The atmosphere has the characteristic that it absorbs the infrared radiation more easily than the visible radiation received from the Sun, and that is what makes the Earth warmer than it would be without an atmosphere.

This event is what makes planet Earth reach temperatures that allow it to be fit for life. The greenhouse effect is therefore a natural phenomenon of the atmosphere, without which life on Earth, as we know it, would not be possible. If the heat is not retained in the atmosphere, the Earth freezes.

Greenhouse effect problem

We have all felt at some point that something like fossil fuels contribute to the generation of greenhouse gases in a negative context. The greenhouse effect itself is not a negative thing (in fact it is necessary), what is negative is that the gases that are artificially emitted can overpower the natural greenhouse effect.

These gases not naturally present in the atmosphere contribute to the retention of heat and keep the planet 30 ° C warmer than if this layer did not exist.

The fact that by burning fossil fuels (coal, oil, natural gas, ...) or by burning a forest, carbon dioxide is produced. If the concentration of CO2 in the atmosphere increases significantly, it could increase the strength of the greenhouse effect. Although not all the factors that intervene in the greenhouse effect are known with precision, this has begun to worry popular opinion at the end of the 20th century.

The increase in the temperature of the planet would have important effects on the life that develops: it would endanger the composition, the capacity of recovery and the productivity of the natural ecosystems, it would alter the climatic regions and the oceanic currents, with possible important consequences on human activities Within the scientific community there is no consensus of the exact consequences. Even so the most catastrophic theses maintain that these problems would be the following:

  • Desertification and droughts, which cause pandemics of hunger.
  • Deforestation, which further increases the change.
  • Melting of Antarctic ice, which causes a rise in sea level, submerging coastal cities causing flooding.
  • Destruction of ecosystems.

Greenhouse gases

Greenhouse gases Greenhouse gases are responsible for this effect in the atmosphere. We list them in order of importance

  • Water vapor (H2O)
  • Carbon dioxide (CO2)
  • Ozone (O3)
  • Other gases in smaller proportion.
    • Methane (CH4)
    • Nitrous oxide (N2O)
    • Sulfur hexafluoride (SF6)
    • CFC

These gases have a strong capacity to absorb heat energy in the infrared region of the spectrum.

Kyoto Protocol

The Kyoto Protocol is an international agreement that attempts to globally limit greenhouse gas emissions. The protocol arises from the international concern about global warming that could increase the uncontrolled emissions of these gases.

The agreements that were carried out in the Kyoto Protocol in 1997 were:

  • The signatory industrialized countries undertake to reduce greenhouse gas emissions by 5% in the period from 2008 to 2012 with respect to 1990.
  • Rich countries must reduce their gas emissions by 25% to 40% by 2020, compared to 1990.
  • The long-term negotiation establishes that the increase in temperature must be below two degrees with respect to pre-industrial levels. This objective will be revised because it does not exceed 1.5 degrees.
  • Adaptation of less industrialized countries to deal with disasters related to climate change.
  • Industrialized countries should promote strategies to lower carbon emissions and developing countries should limit emissions with appropriate national plans and actions.
  • Action plans must be submitted every two years to an international control and verification system, although they must be done in a non-instructive, non-punishable and respectful manner.
  • The industrialized countries must contribute $ 30,000 million in three years, until 2012 and mobilize resources up to $ 100,000 per year in 2020.
  • The aid will be channeled through a fund with 24 members and in which 12 will come from rich countries and others.

Greenhouse effect and solar energy

Usually the concept of greenhouse effect is used globally to talk about an environmental problem on Earth. However, the same effect occurs in a certain area of solar thermal energy.

Solar collectors are used in solar thermal installations. The function of solar collectors or solar collectors is to capture the heat from solar radiation. One type of these solar panels, the flat-based solar collector, is designed to recreate the greenhouse effect on a small scale and thus prevent heat from escaping from the solar collector. In this way, the performance of this renewable energy source is increased.

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Last review: April 26, 2017

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