We explain what the greenhouse effect is and what its causes and consequences are. In addition, its characteristics and possible solutions.
What is the greenhouse effect?
The greenhouse effect is a physical process by which radiation emitted by the planetary surface and received from the Sun is absorbed by gases in the atmosphere , causing an increase in temperature and humidity.
The greenhouse effect is a natural phenomenon that enables life on Earth . If the gases in the atmosphere did not retain heat, the temperature on the planet would be 30 degrees lower.
However, in recent centuries the contamination of carbon dioxide has caused greater its heat retained in the atmosphere, causing climate change worldwide. For this reason, at this time the greenhouse effect has become an ecological problem .
A greenhouse is a construction that allows the sun's heat to enter but, due to the absence of ventilation, does not let it out. Greenhouses are used to grow vegetables that require high levels of temperature and humidity.
The earth's atmosphere produces this same effect since it allows the solar rays to reach the earth's surface and then partially retains its energy, thanks to the layer that its gases form. Thanks to the fact that the atmosphere functions as a greenhouse , life that requires a certain minimum temperature to survive can develop on the earth's surface .
However, when we speak of the greenhouse effect, we refer to the moment when the amount of heat that the atmosphere receives is greater than the amount of heat that it manages to disperse into outer space, producing a progressive increase in temperature.
Causes of the greenhouse effectThe unnatural greenhouse effect is caused by excess carbon dioxide in the atmosphere . It increased from the end of the 18th century, due to industrial development . This increase is due to the intensive use of fossil fuels as an energy source both in industrial activities and in transportation.
Another cause is deforestation , since trees are responsible for reducing the amount of carbon dioxide, and by losing large areas of forest this gas remains in the atmosphere for longer.
Consequences of the greenhouse effectThe direct consequence of the increase in the greenhouse effect is global warming . In turn, global warming causes the melting of the poles , raising the sea level and decreasing the reserves of drinking water for humanity.
Furthermore, many species such as corals cannot survive a change in temperature . The decline in biodiversity has unpredictable consequences on the biological balance of the planet.
Global warming not only manifests itself in an increase in temperatures but also in unexpected atmospheric phenomena , such as more hurricanes and abnormal rainfall.
Greenhouse gasesThe main gas that maintains the natural greenhouse effect is water vapor . Second, carbon dioxide, despite being a gas that makes up a minimal percentage of the atmosphere (only 0.035%). Therefore, any variation in the amount of carbon dioxide in the atmosphere has a profound impact on the greenhouse effect, since small amounts produce large effects.
Carbon dioxide in the atmosphere is long-lived : 50% of it takes 30 years to disappear, but 30% will take centuries to degrade while the remaining 20% will remain for thousands of years.
The other gases involved in the greenhouse effect are methane, nitrous oxide, ozone, and chlorofluorocarbons . The latter is not a gas naturally present in the atmosphere, but is the product exclusively of human action.
Radiation receivedSolar energy reaches the earth in the form of light and heat . The energy that comes from the sun is 341 Watts per square meter and is short wave. This energy is directed partially to the atmosphere (157 Watts) and partially to the earth's surface (184 Watts).
Emitted radiationThe Earth not only receives heat from the sun but also emits heat. This occurs because all bodies that have a temperature above absolute zero (zero Kelvin, 273.15 degrees C) radiate heat. The heat that the earth's surface radiates annually is 396 W per square meter and is infrared radiation. This heat is also partially trapped by the atmosphere and sent back to the earth's surface.
The sum of the sun's energy and the energy radiated by the surface is the total amount of heat that the atmosphere receives and that must be eliminated to maintain a balance .
Reflected radiationBoth the surface of the earth and the atmosphere reflect part of the energy received by the sun. In other words, that energy does not remain in the atmosphere but is dispersed outside of it . The amount of energy reflected jointly by the surface of the earth and by the atmosphere is 102 watts per square meter, that is, less than a third of the radiation received from the sun.
The objects that reflect the most energy are those with light colors, such as snow or clouds . Dark colored objects absorb it. An important part of the infrared radiation emitted by the surface of the Earth also passes through the atmosphere and is scattered in space.
Climate changes of the greenhouse effectBoth the infrared radiation from the earth's surface and the solar energy that is not scattered is absorbed by the atmosphere, the earth's surface, living beings and objects, maintaining a constant cycle that is the natural greenhouse effect of our planet.
The energy that is found in the atmosphere causes natural climatic changes such as temperature increases or decreases, winds and rainfall .
For this reason, while the entry and exit of heat from the atmosphere remains constant, meteorological phenomena are predictable and seasonal. However, when the greenhouse effect is excessive and the atmospheric temperature increases, unpredictable phenomena occur , such as the multiplication of hurricanes , tsunamis , excessive rainfall, among others.
International agreements on the greenhouse effectVarious countries of the world signed an agreement to fight against climate change caused by the greenhouse effect, within the framework of the United Nations Framework Convention on Climate Change:
- Kyoto Protocol . Signed in 1997, it introduceslegally binding targets for the reduction of greenhouse gas emissions. The second period of the protocol is currently in force, until 2020.
- Paris Agreement. It was held in 2015 but its application will be in 2020, at the end of the Kyoto Protocol. Its objective is to promote sustainable development , that is, to develop economies without increasing gas emissions produced by industrialization .
How to reduce the greenhouse effect?To avoid the emission of greenhouse gases, various countries seek to replace fossil fuels with clean energy sources, such as solar, wind or geothermal energy.
In addition, in all the large cities of the world it is aimed to reduce the pollution caused by means of transport, promoting the use of public transport and bicycles.
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Cultural journalist with great interest in education and technological innovation in the classroom. The future passes through technology and it is already here. .