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Definition of greenhouse effect

Definition of greenhouse effect

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

It is called the greenhouse effect due to the similarity with the functioning 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 the heat. That is why this natural phenomenon has been called the greenhouse effect.

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

How the Greenhouse Effect Works

At the time 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 been able to enter the atmosphere reaches the Earth's surface. This causes the surface to warm up and some of this heat is sent in the form of radiation, but at wavelengths greater than that of the Original solar radiation.

Of the infrared radiation that transmits the terrestrial surface, only an important part (approximately 90%) will be able to re-cross the atmosphere and will go out into space. The rest of the radiation heats the gases in the atmosphere and their heat energy stays there, so the planet is surrounded by a set of hot gases that contribute to heat it. The atmosphere has the characteristic that more readily absorbs infrared radiation than the visible radiation received from the Sun, and that is what makes the Earth hotter than it would be without atmosphere.

This event is what makes the 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

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 emitted of artificial form potentiate in excess 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 when burning fossil fuels (coal, oil, natural gas, ...) or a forest burns, carbon dioxide is produced. If the concentration of CO2 in the atmosphere increases significantly, it could increase the strength of the greenhouse effect. Although all factors involved in the greenhouse effect are not precisely known, this has begun to preoccupy popular opinion in the late twentieth century.

The rising temperature of the planet would have significant effects on life: it would endanger the composition, resilience and productivity of natural ecosystems, alter climatic regions and ocean currents, with potentially significant consequences on Human activities. Within the scientific community there is no consensus on the exact consequences. Still the most catastrophic theses hold that these problems would be the following:

  • Desertification and droughts, which cause famine pandemics.
  • Deforestation, which further increases change.
  • Fusion of Antarctic ice, which causes an ascent of the sea level, submerging coastal cities causing floods.
  • Destruction of ecosystems.

Greenhouse gases

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

  • Water vapor (H2O)
  • Carbon dioxide (CO2)
  • Ozone (O3)
  • Other gases to a lesser extent.
    • Methane (CH4)
    • Nitrous oxide (N2O)
    • Sulfur hexafluoride (SF6)
    • CFC

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

Kyoto Protocol

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

The agreements that were implemented in the Kyoto Protocol in 1997 were:

  • Signed industrialized countries commit to reducing greenhouse gas emissions by 5% in the period 2008 to 2012 compared to 1990.
  • Rich countries must reduce their greenhouse gas emissions by 25-40% by 2020, by 1990.
  • Long-term negotiation, states that the temperature increase must be below two degrees with respect to pre-industrial levels. This goal will be revised because it does not exceed 1.5 degrees.
  • Adapt the least industrialized countries to address climate change disasters.
  • Industrialized countries should promote strategies for lowering 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 way that is non-instructive, non-punishable and respectful.
  • Industrialized countries must provide $ 30 billion in aid in three years, by 2012 and mobilize resources to $ 100,000 per year by 2020.
  • The aid will be channeled through a 24-member fund and 12 of which will come from rich countries and others.

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Last review: April 26, 2017