Greenhouse Effect

The greenhouse effect is a naturally occurring phenomenon that warms the earth’s surface. It occurs when specific gases in the atmosphere trap heat from the sun, thereby inhibiting its dissipation into space.

1.0What is a greenhouse?

A greenhouse is a structure with transparent walls that trap heat from sunlight, creating a warm environment for plants to grow. Greenhouses are commonly used in agriculture for growing vegetables, fruits, flowers, and other plants. They can range from small backyard structures to large commercial operations. The controlled environment inside a greenhouse allows growers to regulate factors such as temperature, humidity, and light, which can greatly enhance plant growth and productivity.

2.0What is the greenhouse effect?

• The greenhouse effect refers to the phenomenon where certain gases in the Earth's atmosphere, such as water vapor, carbon dioxide, nitrous oxide, ozone, and methane, act like the panes of glass in a greenhouse. These gases allow sunlight to enter the Earth's atmosphere but trap a portion of the heat that is radiated back from the Earth's surface, thereby warming the planet.
• When sunlight enters the Earth's atmosphere, it penetrates through the greenhouse gases and reaches the Earth's surface, where it is absorbed by land, water, and the biosphere. This absorbed energy is then re-radiated back into the atmosphere in the form of heat. While some of this heat escapes into space, much of it is retained within the atmosphere by the greenhouse gases, contributing to the overall warming of the planet.
• The greenhouse effect is a natural process that is vital for maintaining the Earth's temperature at a level suitable for supporting life. Without it, the Earth would be too cold for humans, plants, and animals to survive. However, if the greenhouse effect becomes intensified, it can lead to an increase in the Earth's average temperature, a phenomenon commonly referred to as global warming.
• Even a slight elevation in global temperatures can have significant implications for human societies, ecosystems, and biodiversity. Therefore, it is crucial to monitor and understand the factors contributing to the greenhouse effect and take steps to mitigate its potential adverse effects on the planet.

3.0Greenhouse Effect Diagram

4.0Greenhouse Gases

Greenhouse gases refer to the gas in the earth's atmosphere that retains heat and leads to the greenhouse effect. Though the effect is important for preserving the Earth's temperature warm enough for life, excessive levels of greenhouse gases could be responsible for global warming and subsequently lead to climate change. Here is a comprehensive note on greenhouse gases, sources, impacts, and control measures:

1. Carbon Dioxide (CO₂) :

• Sources : Emitted from fossil fuel combustion (coal, oil, and natural gas), land clearing (deforestation), and industrial processes like cement production.
• Emissions : Though not very efficient in trapping heat of any GHG, its enormous emissions have made it the most significant contributor to anthropogenic global warming.
• Lifespan : Hundreds of thousands to thousand years.      

2. Methane (CH₄) :

• Source : Emissions are associated with coal, oil, and gas production and transportation. In addition, it is generated by livestock (enteric fermentation), landfills, and rice paddies.
• Strength : Methane is more than 25 times as strong over a 100-year time frame compared to  CO₂ as a heat-trapping gas, thus a very strong greenhouse gas.
• Longevity : About 12 years, though it has a huge short-term impact.

3. Nitrous Oxide (N₂O):

• Source : Emitted from agricultural and industrial practices, particularly by synthetic fertilizers application and from burning fossil fuels.
• Effectiveness : It is 300 times more potent than  CO₂ in trapping heat.
• Lifetime : It lingers in the air for more than 100 years.

4. CFCs and HFCs :

• Source : CFCs were used in refrigeration, air conditioning, and spray cans. Currently, HFCs are the substitute in most of these applications.
• Effect : Extremely potent GHG, depletes the ozone layer. HFCs do not reduce the ozone layer but are very strong GHGs
• Persistence : It can persist for hundreds of years in some cases.

5.0Causes of Greenhouse effect

There are several activities that contribute to the increasing in greenhouse gases which ultimately increase the greenhouse effect:

1. Burning Fossil Fuels : The combustion of fossil fuels such as coal, oil, and natural gas for electricity generation, transportation, heating, and industrial processes releases large amounts of carbon dioxide (CO₂) and other greenhouse gases into the atmosphere.
2. Deforestation : Cutting down forests reduces the number of trees that can absorb CO₂ from the atmosphere through photosynthesis. Additionally, when forests are burned or cleared, the carbon stored in trees is released as CO₂.
3. Agricultural Practices : Certain agricultural practices, such as livestock farming (which produces methane through enteric fermentation and manure management) and rice cultivation (which emits methane from flooded rice paddies), release significant amounts of methane (CH₄) and nitrous oxide (N₂O).
4. Industrial Processes : Various industrial activities, such as cement production, chemical manufacturing, and the use of certain solvents and refrigerants, release greenhouse gases such as CO₂, methane, and fluorinated gases such as CFCs and HCFCs. 

6.0Environmental Impacts of the  Greenhouse Effect

The greenhouse effect is a natural phenomenon that makes the Earth warm enough to be an abode for life by retaining heat in the air. However, with human activities, such as burning fossil fuels and felling trees, it has resulted in an exaggeration of this very phenomenon leading to global warming and many other environmental effects :

1. Global Warming : Global mean temperature rose approximately 1.2°C (2.2°F) over the last century through 2008, with some earlier parts of this rise having taken place since about 1880. This rise in temperature is associated with observed rises in melting glaciers, decreases in ice mass in glaciers outside of Greenland and Antarctica, and increasing sea levels.
2. Sea Level Rise : When warming occurs, polar ice melts and ocean waters expand, causing sea levels to rise with that. This seriously threatens many coastal regions worldwide, where millions of people stand to lose their homes and damage their ecosystems and infrastructure.
3. Increased Extreme Weather Events : A warm climate will lead to increased frequency and severity of weather-related events including heatwaves, hurricanes, floods, and droughts. Such occurrences can have devastating impacts on communities, economies, and ecosystems.
4. Ocean Acidification : Apart from warming the planet, elevated levels of CO₂ dissolve into the oceans. Ocean acidification has created a threat to marine life, especially organisms whose shells consist of calcium carbonate, such as corals and certain species of plankton.
5. Loss of Biodiversity : Climate change poses a threat to biodiversity through habitat disruption and displacement or shifts in species distribution, increasing the risk of species extinction. Of most concern in this regard are reef tracts that have high sensitivity to changes in temperature.
6. Agricultural Disruption : Changes in the pattern of temperature and precipitation can cause the productivity of agriculture. This threatens food security in most regions around the globe.

7.0Controlling the Greenhouse Effect and Climate Change

To mitigate the impacts of an intensified greenhouse effect, communities around the world are trying to reduce releases of greenhouse gases and adapt to climate change. Among the various measures taken by different countries, some of the most crucial ones include the following:

1. Shift to Renewable Energy : Cutting down reliance on fossil fuel and mainly depending on renewable energy sources such as solar, wind, and hydroelectric power may help reduce  CO₂ emissions considerably.
2. Energy Efficiency : Increasing efficiency in industries, buildings, and transportation can decrease energy demands and thus their impact on the environment.
3. Afforestation and Reforestation : More carbon dioxide will be absorbed, therefore reducing the overall concentration of greenhouse gases in the atmosphere.
4. Carbon Capture and Storage (CCS) : This is a CCS technology that captures  CO₂ from the exhausts of power plants and industrial sources before it will otherwise have a chance to enter the atmosphere.
5. International Treaties : 

• The Kyoto Protocol: An international treaty adopted in 1997 in Kyoto, Japan, whose goal is the reduction of GHG emissions in a fight against climate change. This legally binding agreement binds developed countries by their "common but differentiated responsibilities," since they - historically responsible for most of the GHG emissions - are said to have caused the current situation.
• The Paris Agreement : That was reached in 2015 is a global effort by countries to reduce the rise of global temperatures to below 2°C above pre-industrial levels. It was a commitment from the countries to cut on emissions and adapt to climate change.

6. Social Mobilization and Policy Change : It is the responsibility of governments, businesses, and the people to address climate change through policy change, behavioral change, and social mobilization.