Table of content Sl

Table of content
Sl.no Topics Page no
1
Introduction 2
2 Greenhouse model of atmosphere 3-4
3 Major and minor gases affecting the atmosphere’s absorbing heat capacity 4-5
4 Trend in atmospheric carbon dioxide since 18th century 5
5 Likelihood of global warming and climatic change in 21st century 6-7
6 Analysis and discussion 8
7 Conclusion 9
8 References 10
Introduction
The greenhouse effect is a natural mechanism crucial to life on earth, nonetheless human activity has changed the balance in this mechanism. The greenhouse effect is a natural course that warms the earth’s surface. In the present day, the word, greenhouse effect fallaciously indicates the unnatural increase in temperature within earth’s atmosphere due to man- made hazards. If the effort turn out to be stronger, then the earth’s atmosphere could become warmer than normal temperature. Even a slight excess warming may result in trouble for humans, animals and plants.

A warming global climate is understood to be as a consequence of the accumulation of greenhouse gases in the atmosphere and affected by the release of manufacture and human activities such as burning of fossil fuels, deforestation and agriculture have affected the concentration of greenhouse gases in the atmosphere to rise considerably.

At the present, the way climate system will respond to these human activities is tough to foresee, moreover numerous courses are not understood well though. One undisputed reality though, is the fact that the global climate system will respond to increasing temperature. Furthermore, this response could have irreversible costs for the habitability of this planet, and impact various lives and ecosystem.
Greenhouse model of the atmosphere

Fig 1. www.realscience.org.ukThe mechanism of greenhouse effect is that;
Solar energy passes through earth’satmosphere, and some this is reflected back into space.

The rest of the sun’s radiation is absorbed by the lands and oceans.

The earth radiates thermal energy which is also known as infrared radiation towards space.

Some of this heat is trapped by greenhouse gases, keeping the earth warm.

Human activities such as burning fossil fuels, agriculture and land clearing are those activities that leads to increasing the amount of greenhouse gases released into the atmosphere.
This leads to of trapping extra heat and which consequently leads earth’s temperature to rise. This warmingoutcome of the greenhouse gases is named the “Greenhouse effect”.

What atmosphere gases contribute to greenhouse effect?
The major and minor gases affecting the atmosphere’s heat – absorbing capacity
In the past period the consequence of greenhouse gases raised intensely which result into global warming, and which creates enormous problems.

Human activities are increasing the levels of important greenhouse gases such as carbon dioxide, methane, and nitrous oxide in the atmosphere.

The two most ample gases in the atmosphere, nitrogen and oxygen exert almost no greenhouse effect. Rather,the greenhouse effect comes from major gases such as water vapor and carbon dioxide which is the major gases affecting the atmosphere’s heat absorbing capacity. Methane, nitrous oxide, ozone and numerous other gases present in theatmosphere in lesser amount contribute to the greenhouse effect.
The following table shows the concentration of greenhouse gas and its contribution to greenhouse effect.

Source: Flavin (1989)
The trend in the atmospheric carbon dioxide since 18th century
It is assumed that earth’s greenhouse effect has been strengthened as a consequence of human activities over the 250 years or so. It is observed that the concentration of carbon dioxide has increased by more than 35 percent since the start of the industrial revolution in the mid-18th century.
Carbon dioxide is the most plentiful manmade greenhouse gas. A molecule of carbon dioxide into the air will last about 100 years. Concentration of carbon dioxide has risen over the last few centuries as a result of burning of fossil fuels and land use variations, including large –scale deforestation since 18th century due to start of industrial revolution.

Likelihood of global warming and climate change in the 21st century
Global warming and climate change is interlinked concept. Earth’s history have revealed that, climate has changed many times and has included ice ages and periods of warmth. Natural factors including volcanic eruptions, changes in the earth’s orbit, and the amount of energy released from the sun were the primary factor affecting the earth’s climate before the industrial revolutions. However, as the time passes by, there is a scientific accord that climate variation is occurring, and that human actions are the main driver due to human activities allied with industrialization and ever increasing competition and burning began changing the composition of atmosphere in 21st century.
Global warming is affecting every single part of the world in 21st century. As a result of global warming, the glaciers are melting which are triggering the rise in the sea level. When the level of sea rises, it causes threat to people residing in the low lying regions. Thus, this cause a problem to human and ecosystem.Pollution whether vehicular, electrical or industrial is the main contributor of the global warming in the 21stcentury.
Some of the Evidences of climate change due global warming are;
Global temperature rise
The planet’s average surface temperature has increased about 1.62 degrees Fahrenheit (0.9 degrees Celsius) since the late 19th century , a variation driven essentially by rise in carbon dioxide and other man made emission into the atmosphere. Most of the warming happened in the previous 35 years, with the five warmest years on record taking place since 2010. Year 2016 was recorded at the warmest year. (NASA, n.d).

Shrinking ice sheets
The Greenland and Antarctic ice sheets have declined in mass. Data from the NASA’s Gravity Recovery and Climate Experiment show Greenland lost an average of 281 billion tons of ice per year between 1993 and 2016, whereas Antarctica lost about 119 billion tons during consequent period. The rate of Antarctica ice mass loss has tripled in the last decade.
Lugge glacier outburst
Luge and Thorthormi glacier drains south from the border with china into the pho chhu in Bhutan. In 1994, Lugge experienced a glacier outburst flood which affect huge damage in pho chhu basin. The 1994 GLOF event had a peak ejection of about 2539 cubic meters and extended 200km downstream as flood which caused lot of damage.

Analysis and discussion
The greenhouse effect was named from a gardening tool called greenhouse. Earth’s atmosphere and work of greenhouse does the same thing like Gases in the atmosphere such as carbon dioxide does what the roof of a greenhouse does.
In fact, without greenhouse effect, life on the earth would be impossible since the planet would be too cold. During the day, the sun energy radiates through the atmosphere. Earth’s surface warms up due to sun’s radiation. At night, earth’s surface cools, by liberating the heat back into air. However some of the heat is trapped by the greenhouse gases in the atmosphere. This process keeps our earth warm and can almost be assumed like a coat for the earth.

Nevertheless, when the earth’s atmosphere becomes thick with gases which traps the solar radiation, making the earth warmer than average temperature, it leads to climate change which in turn cause problems to human and ecosystem. In 1985, a large and (representative) group of atmospheric scientists met in Villach,Austria- the result of this meeting was “Villach statement”, which has overcome to recognize as turning point in awareness of greenhouse issues. This statement opens by saying “as a result of increased amount of greenhouse gases, it is now believed that first half of next century a rise of global climate temperature could occur which is greater than any in man’s history.
Thus, many social and economic decision is made on long term project. The easiest method to overcome on greenhouse gas emission is only to purchase less things. Whether by forgoing an automobile or employing a reusable grocery sack, minimizing on consumption of fossil fuels being burned to produce and ship aroundthe globe. Think green whenever making any purchases. For example, if person wants to buy new car, he should buy the one that will last long and which has least effect on the environment.

Thus, the only way to reduce global warming is to reduce the greenhouse gas which includes less use of burning of fossil fuel and industrial things.
Conclusion
Earth’s atmosphere and work of greenhouse does the similar thing that’s why it is named as greenhouse effect.Mankind’s activities predominantly those related industrialization, large scale land clearance and chemically enhanced agriculture are adding increasingly large amount of greenhouse gas to the atmosphere. The main greenhouse gases which emits more to atmosphere and rises global temperature , which consequently brings hazards to human lives and ecosystem is carbon dioxide followed by minor gases like methane, nitrous oxide and some other gases.

Enhanced greenhouse gases leads to increase in global temperature which consequently leads to global climate change. Climate change is result of global warming which has caused melting of glaciers, shrinking ice sheet and rise in temperature of earth and impact on climate change cause human hazards .

Therefore, Substitute or unconventional energy sources and new equipment combined with determined emission reductions are way in decreasing the man’s impact on global warming.

References
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