What is the Greenhouse Effect and How it Causes Global Warming?
“Our house is burning, and we are not doing anything”- let’s start with Greta Thunberg, a 17-year-old world-famous Swedish teenager environmentalist who won the Alternative Nobel Peace Prize in 2019.
“Our house is burning, and we are watching,” meaning our home earth is burning while doing nothing. There must grow curiosity about why the earth is burning and what we should do to put out the fire.
The reason why the earth is burning is called the “greenhouse effect” in the language of science. The question that may arise is, what is this “greenhouse effect”?
Why is this effect created, or why is it called the greenhouse effect?
Green House Effect
A greenhouse is a house whose walls and roof are made mainly of transparent materials such as glass or hard polythene. A suitable and controlled environment for vegetable cultivation is created.
Lack of adequate warmth in cold weather interferes with the cultivation of vegetables, flowers, fruits, and roots.
Therefore, countries that are being had a little sunlight during the winter, houses made of transparent glass or polythene on vegetable, flower, fruit cultivation so that sunlight can enter that closed-house through transparent objects, but the heat generated by it cannot escape from inside.
As a result, even in low sunlight, sufficient heat is generated to provide adequate warmth to grow the vegetables, flowers, and fruits. The cold weather from outside the enclosed house cannot enter because of the inability to ventilate inside and outside.
There was an idea of growing plants in the controlled environment from Roman rule. The Roman Emperor Tiberius used to eat a cucumber-like vegetable daily. Therefore, his gardener used to cultivate vegetables in an artificial system (similar to the greenhouse system) to have available it for his dining every day of the year. Cucumber saplings were then planted in wheeled freight cars that were kept in the sun and then taken out into the light in a closed room to keep them warm.
The greenhouse effect is a process that occurs naturally, like a greenhouse or greenhouse used to grow vegetables in a cold country, which helps to warm the surface or the atmosphere.
In simple words, if we compare the earth to a grain field, some gases, up to 10-15 km above the earth’s surface, surround the ground in layers like transparent glass walls, comparable to a greenhouse.
Green House Effect and Global Warming
The high energy light rays (sort wave and low frequency’s UV and visible light) coming from the sun to the earth’s surface by penetrating the atmosphere and reach the earth’s surface in several processes.
When a ray of light enters the earth’s atmosphere, it is reflected, absorbed by the clouds and the particles in the atmosphere.
The distribution of the total radiation energy on earth is the following.
- 26% reflected and scattered by clouds and particles in the atmosphere
- 19% absorbed by the atmosphere and clouds
- 51% absorbed by the earth’s surface
- 4% reflected back by the earth’s surface
The Earth’s surface reflects this 4% in the atmosphere at low energy (Infrared ray- Longwave and high frequency’s invisible ray).
Some gases exist, i.e., CO2 and other gases in the infrared zone, and most of the infrared emitted by the clouds and the Earth retained CO2 and other gases to be returned to the Earth’s surface.
All the sun rays absorbed by the Earth’s surface (51%) are later on reflected in the atmosphere, i.e., the sort wave coming to the Earth’s surface is reflected as low energy radiation (Longwave) in the infrared zone of the atmosphere.
The reflected low energy radiation by the earth surface absorb by the gasses present in the troposphere (Infrared region i.e., up to 10- 15 km.) above the Earth’s surface are IR active and so absorb the radiation without allowing it to escape.
The absorbed radiation by the gases are converted into heat energy and increases the surface temperature. Low energy radiation reflected in the atmosphere is repeatedly reflected and absorbed by the Earth’s surface, accelerating the temperature of the atmosphere.
As the amount of gases in the atmosphere increases, the low-energy radiation absorption and reflection phenomenon will increase repeatedly. The temperature of the atmosphere and the Earth’s surface also rises simultaneously.
These gases are called Greenhouse Gases (GHG), and the layer of gas created like transparent glasses cover around the Earth up to 10-15 km above the Earth’s surface, which raises the surface temperature of the Earth like a greenhouse is used in the agriculture process is called Greenhouse Effect. And the zone covered by the greenhouse is called Inferred Region.
Greenhouse gases are mainly water vapor (H2O vapor), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ground-level ozone (ground-level O3), and chlorofluorocarbon (CFCl3).
At the formation stage, about 4.6 billion years ago, there was no atmosphere on Earth. Some gases were emitted from the Earth’s surface, and the interaction of all those gases creates the Earth’s atmosphere, which is still going on. The outer planets have a deep atmosphere made up of hydrogen and helium.
The inner planet earth’s early atmosphere was hardly the life-sustaining blanket of air that it is today; most scientists believe that the main constituents then were nitrogen gas and carbon dioxide, but no free oxygen.
The atmosphere at the beginning of Earth’s creation is called the Earth’s pristine or primitive atmosphere. The primitive atmosphere contained ammonia (NH4), methane (CH4), and small amounts of carbon dioxide (CO2).
There is no evidence for free oxygen in the atmosphere until about 2 billion years ago when photosynthesizing bacteria evolved and began taking in atmospheric carbon dioxide and releasing oxygen. The amount of oxygen in the atmosphere has risen steadily from 0 percent 2 billion years ago to about 21 percent today.
As a result of the reaction of these gases, oxygen and carbon dioxide are produced and the surface temperature rises. This creates an opportunity for life to begin on earth. Basically, life on earth would not exist without greenhouse gases.
Because the average surface temperature without greenhouse gases is -180 Celsius (0°Fahrenheit), on the other hand, the average surface temperature with greenhouse gases is currently 15 ° Celsius (59 ° Fahrenheit).
As a result of human activities, especially since the Industrial Revolution of 1750, the greenhouse gases in the atmosphere have been increasing rapidly.
The concentration of carbon dioxide in the atmosphere was 280 ppm in 1750, 315 ppm in 1958, 380 ppm in 2005, 390 ppm in 2010, and 418.16 ppm in May 2020.
This is easily predictable that the amount of greenhouse gases is increasing rapidly. (PPM – parts per million = milligrams per litre (mg / L) i.e. milligrams per litre).
Unplanned development in the name of civilization’s development, the immense demand of the people, the ambition to get more and more benefits, and the preference for comfort have led to a growing increase in greenhouse gases.
As a result, the activity of the greenhouse effect is increasing day by day. And the planet called Earth is getting warmer, our house is burning, our home is burning, sea level is rising, glaciers are melting, lowlands are sinking, islands and island states are sinking.
Human habitation is on the verge of disappearing into the abyss of the sea.
In the meantime, many low-lying coastal areas of East Asia, Australia, and the Solomon Islands have been submerged.
If global warming continues to rise in this way, climate experts fear that one-third of the
landmass of Bangladesh, which is coastal, is likely to sink into the sea by the 21st century, and then 1 to 3 crore coastal people in Bangladesh will have to be relocated from coastal areas ( 1 crore = 10 million)
Rising temperatures are also causing massive changes in the Earth’s climate, changing seasons, squeezing the winter, changing the rain pattern.
Due to untimely floods, people’s livelihoods including crop fields are severely damaged, due to the change of seasons, the agricultural calendar is not being maintained properly, which is seriously affecting agricultural productivity, etc.
As a result, scientists predict that the Earth’s temperature will reach a catastrophic level by 2050 if it does not control the current rate of global warming.
Therefore, to keep the Earth habitable, we must reduce greenhouse gas emissions, gradually reduce emissions to zero, and intensify the process of reducing greenhouse gas emissions into the atmosphere.
Of the greenhouse gases, carbon dioxide (CO2) alone contributes 55% to change the intensity of the Earth’s greenhouse effect.
Among other gases, chlorofluorocarbons (CFCs) contribute 25%, methane (CH4) 15%, and nitrous oxide (N2O) 5%.
The following table compares the increase in greenhouse gases in the atmosphere between 1750 and the present:
The comparison of the number of greenhouse gases in 1750 and 2020 are given below: –
| Name of greenhouse gases (GHGs) | At earth atmosphere (up to 10-15 km. from earth surface) in ppm | Remarks | |||
| At 1750 | At present (2020) | Amount | Percentage of increasement | ||
| CO2 | 280 | 417.16* | 137.16 | 48.99 | *As per CO2.earth report, Published on n May 2020. |
| CH4 | 0.700 | 1.869** | 1.169 | 170.40 | ** As per WMO Bulletin, Published on 25 November 2019) |
| N2O | 0.270 | 0.33311** | 0.061 | 123 | |
| Ground level, O3 | 0.237 | 0.337*** | 0.337 | 42 | *** As per WIKIPEDIA, measurement in 2013. |
The increase in CO2 in the atmosphere is mainly due to human activities.
The main sources of this gas are fossil fuels such as petrol, diesel, octane, lubricants, coal, gas, etc. in industry, transportation, space heating or cooling, power generation, cooking, etc.
Besides, cutting trees and deforestation is increasing the amount of carbon dioxide in the atmosphere. About 65% of the CO2 in the atmosphere comes from fossil fuels, and the remaining 35% comes from deforestation.
The main reasons for the increase in methane (CH4) are agricultural work, animal husbandry, insect activities, landfilling of waste/decomposable materials, extraction from coal, fossil fuel mining, cooking, electricity generation, fertilizer production, use of natural gas as vehicle fuel.
The amount of nitrous oxide N2O in the atmosphere increases mainly due to land use. Excessive N2O levels in the atmosphere are rising due to the combustion of fossil fuels, burning or decomposition of animal and plant bodies, decomposition of plants as a result of landfills, agriculture, ocean, fire, grassland, etc.
Chlorofluorocarbon (CFCl3) is a low-boiling solvent synthetic gas that has been used in refrigeration devices such as refrigerators, air conditioners, and aerosols as freon gas.
Its molecules are so powerful that it destroys the ozone in the ozone layer, creating holes in it that allow the sun’s ultraviolet rays to reach the earth directly.
As the earth’s temperature rises, ultraviolet rays cause a variety of complex diseases, including skin cancer. Chlorofluorocarbons are more widely responsible for global warming than CO2, N2O, and CH4.
Chlorofluorocarbon molecules are very strong. One molecule of chlorofluorocarbons is 380,00,000 times stronger than one molecule of carbon dioxide, 15,20,000 times stronger than one molecule of methane, and 10,000 times stronger than one molecule of nitrous oxide.
The chemical reaction to the destruction of the ozone (O3) by chlorofluorocarbon CFCl3 (tri-chlorofluorocarbon) is as follows:
CFCl3 + hν → CFCl2 + Cl. (hv = 240 nm wavelength)
Cl. + O3 → ClO. + O2
ClO. + O → Cl. + O2.
In such a cycle reaction, one atom Clo. Radical destroy 100,000 atoms of ozone (O3).
Therefore, the Montreal Protocol was signed in 1987 at the United Nations initiative to ban the production and use of chlorofluorocarbons along with limiting the other ozone-depleting gases.
Since then, the use of chlorofluorocarbons in developed countries has dropped to zero. Even in countries like ours, usage is slowly becoming limited.
Studies show that the shape of the ozone hole created at the North and South Poles has been steadily declining over the past two decades due to the Montreal Protocol.
Ozone (O3) exists at two layers in the atmosphere. Ozone at the height of 20-30 km above the surface of the earth is very good ozone that benefits the fauna and flora of the planet by absorbing the ultraviolet radiation of sunlight.
The ozone that exists at an altitude of 10-15 km above the earth’s surface is the ozone at earth’s surface (Ground level, O3), which causes very dangerous air pollution, resulting in the formation of photochemical smog on the earth’s surface. Photochemical smog is a toxic gas that can harm the life of animals and plants.
Smog kills 24,000 people each year in the United States. Cities like New York, Los Angeles, California, etc. in America have been affected by smog more than once and caused millions of deaths.
The most interesting thing is that on July 26, 1943, when a sudden smog spread across New York City, and darkness fell and the townspeople had difficulty breathing, the idea arose among the citizens that the Japanese had attacked their city with chemical weapons.
Water vapor (H2O) is the most harmful greenhouse gas. Molecules of water vapor intensely absorb low energy radiation reflected from the earth’s surface.
There is no control limit on the amount of water vapor. The higher the amount in the sky, the hotter the surface will feel. Again, the warmer the surface, the more water vapor will be generated.
Thus, the production of water vapor (H2O) is beyond the direct control of humans. If the production/emission of other greenhouse gases (CO2, N2O, CH4, CFCl3, Ground level O3), which can be controlled by humans for the most part.
If we controlled the emission of other greenhouses except for H20, vapor, the rate of global warming could be greatly reduced. It is possible to bring the quota to zero through the program.
However, CO2 emissions from greenhouse gases can be controlled to a large extent. The United Nations has set a target of reducing CO2 emissions to zero by 2050. The table below shows the measures and programs for greenhouse gas sector-based emissions.
| Sector | Amount (%) | Produce GHGs | Causes | How can protect and reduce the emission of GHG |
| Vehicles | 13 | Mainly CO2, CH4, N2O, GL O3, and CFCl3 from airconditioned vehicles. | Burning/Busting of fossils fuels (petrol, diesel, octane, coal, etc.). And the use of air conditioners. | 1. The use of fossil fuel-powered vehicles like diesel, petrol, octane, coal, etc. should be stopped gradually. Instead, cars with solar power or low fuel consumption should be introduced. 2. Make sure to use a Catalytic converter in all vehicles. 3. should limit the fewer passengers caring vehicles i.e., car, Taxies and instead of that much communication should introduce i.e., Buses. It will also help to reduce traffic jams. 4. should use big buses, trains on long-distance journeys. 5. The use of bicycles in short distances like office, school, market should be increased, and walking should be developed. For this, secure bicycle parking should be ensured in offices, schools, playgrounds, markets, etc., and pavements should be ensured for safe walking. |
| Power generation | 26 | CO2, CH4, N2O, GL, O3 and CFCl3 from air condition systems. | Burning/Busting of fossils fuels (petrol, diesel, octane, coal, etc.). And the use of air conditioners. | 1. Fossil fuels and atomic power generation should close day by day, instead of that green energy g Instead of fossil fuels and nuclear power plants such as diesel, petrol, coal, etc., green generation to be introduced. 2. For Particulate Matter, harmful gases removal in Chimney, Settling Chamber, Cyclone Collectors, Electrostatic Precipitous, Coal burring PP, Wet cleaning process should be used. |
| Industries, Factories | 19 | CO2, CH4, N2O, GL, O3, and CFCl3 from air condition systems. | Burning/Busting of fossils fuels (petrol, diesel, octane, coal, etc.). And the use of air conditioners. | 1. The use of fossil fuels (petrol, diesel, octane, coal, etc.) should be gradually reduced. 2. For Particulate Matter, harmful gases removal in Chimney, Settling Chamber, Cyclone Collectors, Electrostatic Precipitous, Coal burring PP, Wet cleaning process should be used. 3.ISO 14001: 2004 (E) (Environmental Management System) must be ensured in all industrial plants. |
| Agriculture and animals husbandry | 14 | Mainly CH4, N2O is produced from cooking with straw and CO2, GL O3 is produced form weed burning in the open sky and CFCl3 for air conditioning use in food preservation. | 1. Burning/Busting of fossils fuels (petrol, diesel, octane, coal, etc.). And the use of air conditioners. 2. Use of chemical fertilizers and pesticides. 3. Agricultural waste products and weeds in open burning. 4. Medical waste and municipal waste keeping in the open sky or open burning 5. Use of FLCL3 in air conditioners and refrigerators. 6. From Cattle and bird droppings | 1. The use of fossil fuels, electricity in agricultural machinery, irrigation machinery should be reduced. 2. The use of chemical fertilizers and pesticides should be stopped, and organic manure should be used, and insects should be controlled using environment-friendly methods. 3. Agricultural products, weeds, wastes should burn in an environmentally friendly manner instead of open burning. 4. Municipal waste and medical waste should be removed and destroyed systematically. 5. The use of FLCL3 in air conditioners should be stopped completely. 6. Organic manure and cooking manure with cattle and bird droppings should be used for gas and electricity generation. |
| বন ও গাছপালা Forest and Plants | 17 | Mainly CH4, N2O, but CO2 reduce. | 1. Rotten of Plant twigs, leaves, weeds, and burning directly under the open sky. 2. Cutting hills and land fillings. | 1. Damage trees, deforestation, hill cutting must be stopped completely 2. It is necessary to prevent the burning of forests with fire to turn it into agricultural land or grassland. 3. The tree-planting movement needs to be accelerated. |
| Waste and wastewater | 3 | CH4, N2O | Decomposition of organisms and plants | 1. Waste management should be done following the Environmental Management System (EMS). 2. Recycling, reuse should be arranged for Non-organic waste. Gas-electricity generation from organic waste must be arranged, and reuse/ disposal has to be done through liquid waste treatment. |
| Construction of Building structure, Mills factories, communication facilities, etc. | 8 | CO2, CH4, N2O, GL O3, CFCl3 | 1. Bricks are burning, lands filling, and land use. 2. Use of FLCL3 in air conditioners and refrigerators. 3. Insect spiders breed. | Building factories need to be build using green building technological methods such as non-combustible bricks, reduction of wood consumption, daylight use, minimizing the air conditioning system, and ensuring adequate airflow inside the building factory and keeping the environment open and appropriate. Infrastructure needs to be built by providing tree planting arrangements. |
If we are all aware and trying, it will be possible to reduce greenhouse gas emissions to zero quotas by 2050 as per the targets announced by the United Nations.
We will all be aware and strive; we will reduce the greenhouse gas emissions to zero; we will make the planet Earth habitable – this is the expectation.
Reference:
- Atmospheric Pollution, History, Science and Regulation, Mark Z. Jacobson, Cambridge Uni. Press, 2003
- Environment: Problems and Solutions, DK Asthana, Meera Asthana, Chand Pub. India, 1999.
- Environmental Chemistry, AK De, 4th Edition, New Age International (Pvt)Ltd, India, 2000
- Air Pollution, MN Rao, HVN Rao, Tata-McGraw-Hill, India, 1989.
- Wikipedia.
- Sources: Environment Related Bangla News Portal – GreenPage
