Effects of Climate Change on Agriculture in the outskirts of Kathmandu Valley

Table of Contents

Letter of recommendation

Certification

Acknowledgement

Abstract

Abbreviations

Key Terminologies

List of figures

List of Tables

List of pictures

List of charts

Table of Contents

CHAPTER ONE
INTRODUCTION
Background
Statement of problem
Objectives of the study
Research questions 4 Rationale of the study
Significance of the study
Delimitation of the study

CHAPTER TWO
LITERATURE REVIEW
Climate Change
The Greenhouse effect
Greenhouse Gases
Sulphur-dioxide
Methane
Carbon-dioxide
Carbon-monoxide (CO)
Water vapor
Oxides of nitrogen
Risk of climate change in the context of south Asia
Risk of climate change in the context of Nepal
Nepal as agricultural country
Temperature status of Nepal
The rainfall status of Nepal

CHAPTER THREE
RESEARCH METHODOLOGY
Research design 41 Selection of the study area
Description of the study area
Selection of samples
Sample size
Sources of data
Key informants
Methods of data collection
Key informants interview
Direct observation
Questionnaire Schedule
Group discussion
Formal and informal meetings
Procedures of data collection

CHAPTER FOUR
ANALYSIS AND INTERPRETATION OF DATA
Unknown Virus destroyed the whole farm
New kind of insect devouring the tomatoes
Green Caterpillar in the corn leaves
Holes in the leaves of lady’s figure plant
Strange moth makes hole in the Bitter gourd
Zero Cucumber harvest
Invasion of the new plants and wild grass species
Barren lands
Wheat, Barley and millet are planted no more
Shifting in the crop plantation period
Paddy plantation in the dry field
Epidemic disease in paddy
Cultivation of Corn in the rice fields
Amount of agricultural harvest reduced a lot
Mitigation measures of climate change on agriculture

CHAPTER FIVE
RESULTS, CONCLUSIONS AND RECOMMENDATIONS
Results
Conclusion
Recommendations
Area of further research

REFERENCES

ANNEXES

Acknowledgement

I would like to express my hearty thanks to my supervisor Dr. AradhanaShalpekarfor the help and support she poured over every inch of the manuscript with painstaking attention to detail and of semi finite number of successions to make this thesis a success. I really appreciate her for providing valuable time and quenching my thirst of knowledge. My special thanks go to Mr. YashodhanTripathi Sir for his valuable suggestions and guidance before and during the preparation of this thesis. I want remember the generosity of Mr. Ashok Tripathi Sir for providing me resources in the process of writing this thesis.

I’m grateful to my wife Mrs. DeepaBasnet for her positive motivation and support. I cannot remain without remembering the help and support of Mr. Mohit Prasad Guragain for his special support during the preparation of the thesis. I am very thankful to Mrs. BabitaLabhKayatha for correcting English language mistakes in this thesis.

I would like to thank Mr. TirthaShahi, TikaDahal and all the respondents of PuranoNaikap VDC who helped me directly by sharing information regarding agricultural system and status. I would also like to thank the village secretary, local school principal and agriculture experts for providing valuable information and suggestion.

At last, I want to thank all those who helped me directly and indirectly to complete this research study.

SantoshBudhathoki

Abstract

Nepal is one among the most vulnerable country regarding climate change. The average rise in temperature of Nepal is 0.06o C but the rate is higher in the Himalayas. Climate change has affected almost all the aspects of life among which agriculture is one of the major ones. Therefore the research was purposed to find the effects of climate Change on agriculture in the outskirts of Kathmandu valley.

PuranoNaikap village was selected for the study because it resembles the altitude of all the foothills of Kathmandu. It comprises of all types of topography of hills of Kathmandu valley. The study followed both quantitative and qualitative research methodology. The major tools of data collection were questionnaire schedule, field visit, key informants interview and formal and informal meetings with the concerned stakeholders. Besides that, various sources were used for the desk review to collect secondary data. Purposive sampling technique was used for survey where affected farmers were collected and studied. The study continued for six months’ time.

Many cases of adverse effects of climate change were found in the study area such as untimely rain, infestation of alien plants and grass species, infection of viral disease in tomato and paddy plants, invasion of different harmful insects like GabaroKira and Green Caterpillar. The fields were left barren due to drought in the lands where it used to be wetland throughout the year. There is lack of irrigation facilities and lack of manpower for agriculture.The farms were destroyed by viral disease, moths and different new insects. It was not possible to grow plants without using chemicals as vitamins and insecticides/pesticides. A typical farm of tomatoes occupying the area of five ropanis of land had to be used the chemicals worth of around 40,000 rupees within three months of time. New species of plants like Began belly, Rajbriksha, Mango, Banana, litchi are seen there. The fruits used to be found at the altitude of 600 to 700 meter are now found in the altitude of 1300 to 1500 meter. The tropical plants are shifting towards higher altitudes.

The status of agricultural products was found reduced to a greater extent.The study revealed that rice yield in Kg per ropani decreased by 65%, Maize by 50%, Wheat by 100% and legumes by 40% comparing between 10 years back and now. It was an awful condition. 99% of the households have to buy rice from market while 50% of the households used to sell paddy, wheat, maize and millet before 10 years. The crops like Wheat, Barley and Millet are no more planted in the study area.It was observed that farmers were compelled to cultivate paddy in the dry field due to the shifting back of monsoon season almost one month later. The paddy did not survive well due to lack of water. Some of the plants which were able to survive were destroyed completely by a kind of moth insect. The moth lays eggs in at the tip of paddy plant and goes inside the root which ultimately kills it.It was found that in some of the places, people have planted corn in some places in place of paddy to cope with climate change. Since corn needs less water and can be grown easily, it was one of the good options for them. It is better to replace with corn than to leave it barren.

Abbreviations

AIRS- Atmospheric Infrared Sounder

CBS- Central Bureau of Statistics

CH4 – Methane

CO– Carbon monoxide

CO2 –Carbon-dioxide

DoHM- Department of Hydrology and Metrology

FAO – Food and Agriculture Organization

GDP- Gross Domestic Product

GHG- Green House Gases

GOLF- Glacial Lake Outbrust Flows

H2 SO4 – Sulphuric acid

H2O- Water

ICIMOD- International Centre for Integrated Mountain Development

IEA- International Energy Agency

INGO- International Non-Government Organization

IPCC- Intergovernmental Panel on Climate Change

MM- Millimeters

MOAC- Ministry of Agriculture and Co-operatives

MOE- Ministry of Environment, Science & Technology

NO- Nitric Oxide

NO2- Nitrogen Dioxide

N2 O – Nitrous Oxide

NARC- Nepal Agricultural Research Council

NASA- National Aeronautics and Space Administration

NGO – Non Government Organization

O3 – Ozone

OECD- Economic Co-operation and Development

OH- Hydroxide

PPM- Parts Per Million

SO2 – Sulphur-dioxide

SO3 – Sulphur-trioxide

SSMP- Sustainable Soil Management Program

UNEP- United Nations Environment Programme

UNFCCC- United Nations Framework Convention on Climate Change

USD- US Dollar

VDC- Village Development Committee

Key terminologies

Climate change : The change in the climatic conditions and seasonal variations for a long period of time.

Global Warming: The increase in temperature of the earth due to Green House Gases (GHG).

Outskirts: A part remote from the center (Merriam-Webster Dictionary).

Village Development Committee (VDC): The local governing body which governs a particular village premises only.

Agriculture: The science, art and practice of cultivating the soil, producing crops and raising livestock is known as agriculture.

Ropani: It is a local measuring unit of land. One ropani is equal to 508.74 Meter Square

Pathi: It is also a local measuring unit of mass. One pathi is approximately equal to 4.5 Kg.

List of figures

Figure I: An idealized model of the natural greenhouse effect

Fig II: Annual Greenhouse Emission by Sector

Fig III: Concentration of Methane Gas in the air.

Fig IV: Graph showing the global atmospheric concentrations of CO2

Fig V: Time series of CO2 emission in Nepal

Fig VI: Trapped energy vs air weighted latitude

Fig VII: Climate change vulnerability index

Fig VIII: Flow chart showing the impacts of climate changes in different aspects of environment

Fig IX: Contribution of agriculture to the GDP of Nepal

Fig X: General Trend of average monthly rainfall in Nepal

Fig XI: Trend of total precipitation in Nepal during pre-monsoon, Monsoon and Post-monsoon period

Fig XII:Flow chart showing research design

List of Tables

Table no: 1 Vulnerable group in Nepal

Table no: 2 Highlights of PuranoNaikap Village

Table no: 3 Mitigation measures of climate change on agriculture

Table no. 4: Adaptive measures of climate change on agriculture

List of Pictures

Picture no1: A tomato plant affected by virus

Picture no. 2: TirthaShahi showing the tomato plant affected by virus

Picture no. 3: Disposal pit filled with the infected tomato plants

Picture no. 4 and 5: Mr. Shahi pulling off the infected plants and using insecticides to control pests

Picture no. 6: Green caterpillar in the corn plant

Picture no. 7 A close view of Green Caterpillar in the corn leaves

Picture no. 8: Lady’s Finger plant destroyed by insects

Picture no. 9: Vegetable plants destroyed by new kind of fly

Picture no. 10: Mango species seen in Kathmandu Valley

Picture no. 11: A barren land in the study area due to lack of water

Picture no. 12 and 13: Farmers cultivating paddy in the dry field (left) and dried paddy field due to no rainfall

Picture no. 14: Picture of the paddy cultivated in the dry land taken after one month

Picture no. 15: Corn plants planted in the paddy field due to lack of water

List of Charts

Chart no. 1: Responses of people regarding the reasons for not cultivating wheat, Millet and Barley

Chart no. 2: Perception of respondents on cultivation time of Maize

Chart no. 3: Perception of farmers on the cultivation time of Paddy

Chart no. 3: Perception of farmers regarding the cultivation time of Mustard

Chart no. 4: Percentage of population who planted corn on their field due to less rain

Chart no. 4: Average grain production status per ropani per pathi 10 years back and Now

CHAPTER ONE

INTRODUCTION

Background

Our earth is the only planet with life discovered till now. It is often called as the “Green Planet” or “The Planet with Life”. The reasons for the abundance of life on the earth are the presence of atmosphere, suitable temperature, water, food, shelter, etc. But in these few past decades, the detrimental effects have seen in almost all the components and aspects of the earth including the global warming and climate change. The phenomenons have the adverse effects on the earth so as on all the living things threatening their existence on the earth. Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years). Climate change may refer to a change in average weather conditions, or in the time variation of weather around longer-term average conditions (i.e., more or fewer extreme weather events .Global warming refers to the phenomenon of increasing average surface temperatures of the Earth over the past one to two centuries. The concept is related to the more general phenomenon of climate change, which refers to changes in the totality of attributes that define climate—not only surface temperatures, but also precipitation patterns, winds, ocean currents, and other measures of the Earth’s climate.

Global warming and Climate Change are terms for the observed century-scale rise in the average temperature of the Earth's climate system and its related effects. Multiple lines of scientific evidence show that the climate system is warming. Although the increase of near-surface atmospheric temperature is the measure of global warming often reported in the popular press, most of the additional energy stored in the climate system since 1970 has gone into ocean warming. The remainder has melted ice and warmed the continents and atmosphere. Many of the observed changes since the 1950s are unprecedented over tens to thousands of years.

The effects of climate change are seen in the various sectors in Nepal. One among them is agriculture. Nepal is an agriculture-based country where more than 65% of the population engages in agriculture for livelihood and agriculture shares about 33% of its GDP at current price and 35% at 2000/2001 constant price (MOAC, 2010). The people whose livelihood is obligatory to agriculture are in serious threat of food deficit and hunger. Not only those populaces are affected by the climate change, some of the people who have adapted other professions but greater part of their food is obtained from their field productions are equally affected. There are a big number of such people living in the outskirts of the Kathmandu valley.

Therefore, this research was proposed to explore and mitigate the effects of climate change and global warming in the agriculture sector in the outskirt areas of Kathmandu valley where major portions of their food is produced from their own fields.

Statement of problem

When I was a young boy, my parents used to plant paddy on the month of Ashad (Mid June). The country observes paddy day on the 15th of Ashad which is characterized by the celebration of mud festival and plantation of paddy. The month is called as” the month of paddy plantation”. Most of the paddy plantations had been finished by the end of Ashad. But nowadays there is no any rain on the paddy plantation day and the fields are left barren due to lack of water.

The vegetables cultivated on time are infested by a lot of insects and vermin. Not only that, the unknown diseases have been seen which are very difficult to control. The cultivated crops cannot yield much and vegetables seem impossible to grow without using insecticides, pesticides and vitamins. Some of the insects and plants which were not found in my area are found everywhere nowadays. Some of the fruits which are found in the hot climate of Teraiare now seen in Kathmandu.

Intergovernmental panel on climate change (IPCC) predicts severe losses in agricultural productivity due to high temperature, severe drought, flood conditions, and soil degradation (Cruj et al. 2007, IPCC). At some places hot winds and dust storms are frequent and some areas of Nepal are practically in the grip of drought between the end of March and the beginning of the monsoon in July (Sharma, 1979). In many areas of Nepal, farmers have reported over 50% losses of crops due to erratic rainfall and increase drought (SSMP, 2010).

Objectives of the study

The studyfocused on the observation of the effects of global warming and climate change on agriculture in the outskirts of Kathmandu valley. The objectives of the study were to identify the effects of climate change on agriculture in the surrounding hills of Kathmandu valley. The specific objectives of the study are given below:

- To study the effects of climate change on crop production in the research area.
- To find out shift of agricultural pattern in the research area.
- To suggest some mitigation and adaptation measures in the study area.

Research questions

The study has helped to address the answers of the following questions:

- Is there any relationship between climate change and the agricultural productions?
- Is the agricultural pattern changed in the research area?
- Is there any special effect seen on agriculture due to climate change?
- What may be the possible mitigation and adaptation measures to enhance the agricultural productions?

Rationale of the study

Rice is one of the important and staple foods for most of the people in Nepal and it has long history of cultivation. Due to the slow but visible implications of the global warming, the pattern of weather seems to be gradually changing affecting the entire process of the agriculture (Poudel, 2004). The study deals with the detrimental implications of global warming and unseasonal rainfall on the food crops production. The status of food production is directly related to the livelihood of the people fully dependent on agriculture. The erratic shifting of the rainfall pattern and drought conditions has caused severe effects on GDP.

The farmers in PuranoNaikap fully depend upon rainfall for the paddy cultivation and vegetables production. There is no any other means of irrigation except “Daudali River” which has almost dried out. The people have complained about the decreased crop production and infestation of unknown pathogens and insects. So the study helps to find the rigid change in agriculture and some of the measures to mitigate such changes.

Besides this, we see many plans and programs have been formulated for the farmers who are fully dependent on agriculture but almost no plans and programs are formulated for the people who have adapted other professions but majority of their food is produced from their own fields. So, this research helps the local government to make policies for such populace.

Significance of the study

The study was carried out in the NaikapPuranoBhanjyang, which lies in the western parts of the Kathmandu Valley in the middle hills physiographic region of Nepal. The area resembles most of the topography of the surrounding hills. The farmers have started to abandon the farmland due to various causes so decreasing the crop productivity and increasing economic burden for them. The study has the following significance:

- The study throws the spot light on the actual status of effects of climate change on agriculture in the surrounding areas of Kathmandu valley.
- The research reveals the level of dependency of people living on outskirts of Kathmandu valley on self-produced food.
- The study helps to find the mitigation measures of adverse effect of climate change on food crops.
- The study helps to find the adaptive measures of adverse effect of climate change on food crops.
- The study helps to form policy on the local level to fight against climate change.
- This study serves as the source of literature for the upcoming researchers in the field of climate change.

Delimitation of the study

This research deals with the effects of climate change on agriculture and agricultural products in PuranoNaikap VDC. The limitations of this study are as follows:

- This study is the study of the effect of climate change on agriculture in the outskirt areas of Kathmandu valley. But, the study was conducted only in PuranoNaikap VDC. The study could not take all the areas for observation.
- The study was done only in PuranoNaikap VDC. So, the result may not be generalized for the rest of the places. The result should be compared to the other places in the further research.
- The result of the study is applicable to the local area.
- The study was based on the data provided by various governmental and nongovernmental agencies. The researcher has observed and analyzed the data for the result. The validity of the result depends upon the reliability of the data obtained from the sources.

CHAPTER TWO

LITERATURE REVIEW

Climate Change

According to Oxford Advanced Learners Dictionary (2016), the climate change is defined as “A change in global or regional climate patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels. Furthermore it has defined Climate Change as “changes in the earth’s weather, including changes in temperature, wind patterns and rainfall, especially the increase in the temperature of the earth’s atmosphere that is caused by the increase of particular gases, especially carbon dioxide”.

Humanity is conducting an unintended, uncontrolled, globally pervasive experiment whose ultimate consequences could be second only to nuclear war. The earth’s atmosphere is being changed at an unprecedented rate by pollutants resulting from human activities, inefficient and wasteful fossil fuel use and the effects of rapid population growth in many regions. These changes are already having harmful consequences over many parts of the globe (Trivedi, 2007). This statement shows that the world’s climate is changing due to human activities which harms to the humanity itself. The effects have been seen in different aspects among which agriculture is one of the prominent one.

Narayan BahadurShrestha in his thesis titled “Effect of climate change on Agriculture and farming in Nepal says “ With ever increasing industrialization, excessive use of fuel, and change in use pattern of land in the world, amount of greenhouse gases like Carbon-dioxide, Carbon-monoxide, Chloroflouro carbon, Methane etc. have excessively been increasing which is resulting ozone layer depletion. As a consequence, temperature of the earth has been rising due to the increase in radiation of solar rays. The solar radiation ultimately leads to greenhouse effect which causes climate change in the world”.

Intergovernmental Panel on Climate Change Forth Evaluation Team (IPCC, 2007) has described about very uncertainty of the climate change in the world. Greenhouse gases emission have been increased because of human activities in which role of Carbon dioxide is vital. Prior to industrialized phase in compared to past century, carbon emission was only 278 parts per million (ppm) that has increased up to 379 ppm by 2005. Average earth temperature has increased by 0.74oC. Eleven excessive hottest years out of 12 in the earth has recorded within last 25 years. Scientists have estimated that the temperature of the earth will be increased by 30C till 2100 AD; average increase in temperature will be 1.80 C to 40C accordingly topography so that consequences of climate change, world communities would have to face havoc natural disasters in future.

In the report of UNEP (2007) has stated “Moreover, vector borne diseases like Malaria, Dengue, Encephalitis are being epidemic that caused by climate change. Above different causes are responsible for increasing natural disasters by 3 times within last 30 years. Forest has played a significant role reducing house gases emission though carbon sequestration.”

The Greenhouse effect

ShuvaratnaShakya in his book “New Science, An Introduction” has stated that “Greenhouse effect is warming of the earth’s surface that occurs due to trapping of the sun’s heat by the earth’s atmosphere. Without this effect, the average surface temperature of the earth would be less than present normal temperature. Earth’s atmosphere acts like a blanket or like the glass of a Greenhouse. Different gases like Oxygen, Carbon-dioxide, Methane, oxide etc. are present in the atmosphere which traps sun’s radiation.”

The Greenhouse effect is a natural phenomenon that plays a central role, in determining the Earth’s climate. The hot surface of the sun radiates as a body having equivalent temperature of 5800K. The bulk of the radiation is in the visible wavelength region, 0.4 – 1.0 m, where the earth’s atmospheric gases absorb only weekly. In contrast, the low temperature earth emits radiation to infrared wavelengths for the atmosphere is highly absorbing. In an oversimplified description, the atmosphere lets shorter wavelength radiation in, but does not let the larger wavelength radiation out (Trivedi, 2007). This means that, Greenhouse phenomenon is a natural process which is important too but its extremity has brought implications in the global climate cycles.

Abbildung in dieser Leseprobe nicht enthalten

Figure I: An idealized model of the natural greenhouse effect.

(Source: https://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-1-3-figure-1.html)

The phenomenon of the Greenhouse effect is shown in the figure no I. The Sun powers Earth’s climate, radiating energy at very short wavelengths, predominately in the visible or near-visible (e.g., ultraviolet) part of the spectrum. Roughly one-third of the solar energy that reaches the top of Earth’s atmosphere is reflected directly back to space. The remaining two-thirds is absorbed by the surface and, to a lesser extent, by the atmosphere. To balance the absorbed incoming energy, the Earth must, on average, radiate the same amount of energy back to space. Because the Earth is much colder than the Sun, it radiates at much longer wavelengths, primarily in the infrared part of the spectrum. Much of this thermal radiation emitted by the land and ocean is absorbed by the atmosphere, including clouds, and reradiated back to Earth. This is called the greenhouse effect. The glass walls in a greenhouse reduce airflow and increase the temperature of the air inside. Analogously, but through a different physical process, the Earth’s greenhouse effect warms the surface of the planet. Without the natural greenhouse effect, the average temperature at Earth’s surface would be below the freezing point of water. Thus, Earth’s natural greenhouse effect makes life as we know it possible. However, human activities, primarily the burning of fossil fuels and clearing of forests, have greatly intensified the natural greenhouse effect, causing global warming (IIPC,2007).

Greenhouse Gases

Greenhouse gases are the gases that contribute to the greenhouse effect by absorbing infrared radiation. Carbon dioxide and chlorofluorocarbons are examples of greenhouse gases (Oxford Dictionary, 2007). These gases trap the heat of the sun causing the greenhouse effect. These gases let shorter waves inside the earth to come but do not let longer waves to pass outside the earth.

Different gases such as nitrogen, oxygen, carbon-dioxide, methane, nitrous oxide, etc. are present in the atmosphere. Nitrogen and oxygen do not trap sun’s radiation. The ones that do trap it are the greenhouse gases. Carbon-dioxide gas, methane and water vapor are important greenhouse gases. Heat that is normally re-radiated back into space by the earth is absorbed by these gases which heat the troposphere of the earth’s atmosphere (Shakya, 2015).

The atmosphere of the earth works as the glass of the artificial greenhouse i.e. it allows the short waves to pass through it. These short waves enter to infrared radiation after striking on the earth’s surface, which does not pass easily out through the atmosphere. Water vapor, dust, greenhouse gases like sulphur-dioxide, hydrofluorocarbons, sulphur hexafluoride, carbon-dioxide, carbon monoxide, methane particles, etc. absorb about 37.33% of the infrared radiation. It makes the earth warm and helps in the climate change (Shrivastav, Ghimire, Mishra, Thapa, 2015).

The two most abundant gases in the atmosphere, nitrogen (comprising 78% of the dry atmosphere) and oxygen (comprising 21%), exert almost no greenhouse effect. Instead, the greenhouse effect comes from molecules that are more complex and much less common. Water vapor is the most important greenhouse gas, and carbon dioxide (CO2) is the second-most important one. Methane, nitrous oxide, ozone and several other gases present in the atmosphere in small amounts also contribute to the greenhouse effect. In the humid equatorial regions, where there is so much water vapour in the air that the greenhouse effect is very large, adding a small additional amount of CO2 or water vapor has only a small direct impact on downward infrared radiation. However, in the cold, dry Polar Regions, the effect of a small increase in CO2 or water vapor is much greater. The same is true for the cold, dry upper atmosphere where a small increase in water vapor has a greater influence on the greenhouse effect than the same change in water vapor would have near the surface (IIPC, 2007).

Adding more of a greenhouse gas, such as CO2, to the atmosphere intensifies the greenhouse effect, thus warming Earth’s climate. The amount of warming depends on various feedback mechanisms. For example, as the atmosphere warms due to rising levels of greenhouse gases, its concentration of water vapor increases, further intensifying the greenhouse effect. This in turn causes more warming, which causes an additional increase in water vapor, in a self-reinforcing cycle. This water vapor feedback may be strong enough to approximately double the increase in the greenhouse effect due to the added CO2 alone (IIPC, 2007). Fig II Annual Greenhouse Emission by Sector(Source: Emission Database for Global Atmospheric Research version 3.2, fast track 2000 project)

According to figure no the highest percentage of contribution in the greenhouse effect is made by power plants (21.3%) and the lowest is by waste disposal and treatment. The industrial processes, transportation fuels, agricultural byproducts, fuel retrieval, processing and distribution, residential sources and land use and biomass burning make the contribution of 16.8%, 14.0%, 12.5%, 11.3%, 10.3% and 10.0% respectively. The Carbon dioxide makes 72% of the total gas productions whereas Methane and Nitrous oxide make up 18% and 9% of the total production.

Sulphur-dioxide

The molecular formula of Sulphur-dioxide is SO2. The gas is made up of one atom of sulphur with valency 4 and two atoms of oxygen with valency 2. The gas is reactive and reacts with oxygen molecule to form sulphur trioxide. Thus formed sulphur trioxide reacts with water vapour to form sulphuric acid (Shrivastav et.al, 2015). The reaction involved in the process is shown below.

Abbildung in dieser Leseprobe nicht enthalten

Thus formed sulphuric acid mixes with rain water and falls as acid rain.

Sulphur-dioxide in the atmosphere arises from both natural and human activities. Natural processes, which release sulphur compounds include decomposition and combustion of organic matter; spray from the sea and volcanic eruptions. The main human activities producing sulphur-dioxide are smelting of mineral ores containing sulphur and combustion of fossil fuel. SO2 dissolves in water forming sulphuric acid which is highly corrosive in nature, and this helps in damaging materials and also plant and animal tissues (Bhandari, 2006). The process of formation of sulphuric acid is shown above.

Methane

Methane is the first member of the alkane series made up of one carbon atom and four hydrogen atoms. The molecular formula of methane is CH4. It can absorb heat radiation and hold adding a brick in the process of global warming and greenhouse effect. As a hydrocarbon, it burns with oxygen to produce carbon-dioxide and water vapor which again plays important role in the process of greenhouse effect. The reaction of the process is shown below.

Abbildung in dieser Leseprobe nicht enthalten

Methane is also called as “Marsh Gas” because it is also produced in marshy land. While methane is a more potent greenhouse gas than CO2, there is over 200 times more CO2 in the atmosphere. Example – CO2 levels are 380 ppm (parts per million) while methane levels are 1.75ppm. Hence the amount of warming methane contributes is calculated at 28% of the warming CO2 contributes. Here is a graph that shows the concentration of methane in the atmosphere upto 2010 (IIPC, 2005).

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Fig III: Concentration of Methane Gas in the air. (Source: http://www.eea.europa.eu/data-and-maps/figures/atmospheric-concentration-of-ch4-ppb-1)

The figure has shown the concentration of Methane excessively increasing from 700 ppb in 1750 AD to 1900 ppb in 2010 AD. According to the graph, the rise has been extremely elevated since 1950. Between 1910 and 1950, the curve is elevated up in the unusual manner showing the concentration of methane from nearly 800 ppb to 1100 ppb. During the years 1750 to 1910, the rise in the concentration of methane is just 800 ppb from 700 ppb.

Carbon-dioxide

The molecular formula of carbon dioxide is CO2. It is produced by the major activities like respiration and combustion of the organic and inorganic matters. According to the Fourth Assessment report of IIPC carbon dioxide (CO2) is the second-most important gas which cause global warming and help in greenhouse effect.

The power and industry sectors combined dominate current global CO2 emissions, accounting for about 60% of total CO2 emissions as shown in the figure II. Future projections indicate that the share of these sectorial emissions will decline to around 50% of global CO2 emissions by 2050 (IEA, 2002). The CO2 emissions in these sectors are generated by boilers and furnaces burning fossil fuels and are typically emitted from large exhaust stacks. Coal is currently the dominant fuel in the power sector, accounting for 38% of electricity generated in 2000, with hydro power accounting for 17.5%, natural gas for 17.3%, nuclear for 16.8%, oil for 9%, and non-hydro renewables for 1.6%. Coal is projected to remain the dominant fuel for power generation in 2020 (about 36%), whilst natural-gas generation will become the second largest source, surpassing hydro (IIPC, 2005).

Carbon dioxide not related to combustion is emitted from a variety of industrial production processes which transform materials chemically, physically or biologically. Such processes include:

- The use of fuels as feedstock in petrochemical processes
- The use of carbon as a reducing agent in the commercial production of metals from ores
- The thermal decomposition (calcination) of limestone and dolomite in cement or lime production
- The fermentation of biomass (e.g., to convert sugar to alcohol). (IIPC, 2005)

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Fig IV: Graph showing the global atmospheric concentrations of carbon-dioxide

(Source: http://www.eea.europa.eu/data-and-maps/figures/observed-trends-in-the-kyoto-gases-1)

The figure shows that the amount of carbon-dioxide is increasing in the air. The graph has elevated sharply in between 1950 and 2010 from nearly 226 ppm to 450 ppm. The pattern of rise was quite low from the year 1850 to 1950 from nearly 290 ppm to 225 ppm.

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Fig V: Time series of CO2 emission in Nepal. (Source: CDIAC, 2009)

The figure illustrates the rising trend of Carbon-dioxide emission in Nepal. It shows the increase in the amount of carbon-dioxide is extreme in the decade of 1990s. The graph is straightly elevated from 400 tones to nearly 1250 tones in between the year 1990 and 2000 AD. There is almost no rise in the concentration of carbon-dioxide between the year 1950 and 1960 AD. The trend of CO2 emission is increased from the year 1960 to 100 AD. The increase in the amount of CO2 is extreme which makes Nepal one of the most vulnerable countries for the risk of climate change.

Carbon-monoxide (CO)

It is the odorless and colorless gas produced by incomplete oxidation (burning) of the fuel. As well as wildfires, carbon monoxide is also produced naturally by oxidation in the oceans and air of methane produced from organic decomposition. The reaction is shown below.

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Incomplete oxidation

In cities, the motor vehicle is by far the largest human source, although any combustion process may produce it. Carbon monoxide usually remains in the atmosphere for a month or two. It is removed by oxidation to form carbon dioxide, absorption by some plants and microorganisms, and rain.

When inhaled, it binds to the oxygen-carrying capacity site on the blood’s hemoglobin, which reduces oxygen transport in the body. At high concentrations it is very toxic, causing headaches, dizziness, reduced ability to think, and nausea (Bhandari, 2006).

Carbon monoxide (CO) does not absorb terrestrial infrared radiation strongly enough to be counted as a direct greenhouse gas, but its role in determining tropospheric hydroxide (OH) indirectly affects the atmospheric burden of CH4 (Isaksen and Hov, 1987) and can lead to the formation of Ozone (O3). More than half of atmospheric CO emissions today are caused by human activities, and as a result the Northern Hemisphere contains about twice as much CO as the Southern Hemisphere. Because of its relatively short lifetime and distinct emission patterns, CO has large gradients in the atmosphere, and its global burden of about 360 Tg is more uncertain than those of CH4 or N2O (IIPC, 2007).

Water vapor

The water vapor present in the atmosphere is one of the key players gas affecting the greenhouse effect. The water vapor is produced by varieties of tasks like respiration, transpiration, evaporation. excretion, etc. Some of the researches conducted by NASA have shown that water vapor plays equal role as the carbon dioxide plays in the greenhouse effect.

According to Hasen K. (2008) from NASA in her report “Water vapor is known to be Earth’s most abundant greenhouse gas, but the extent of its contribution to global warming has been debated. Using recent NASA satellite data, researchers have estimated more precisely than ever the heat-trapping effect of water in the air, validating the role of the gas as a critical component of climate change. Andrew Dessler and colleagues from Texas A&M University in College Station confirmed that the heat-amplifying effect of water vapor is potent enough to double the climate warming caused by increased levels of carbon dioxide in the atmosphere.

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Fig VI: Trapped energy vs air weighted latitude (Source: https://www.nasa.gov/topics/earth/features/vapour_warming.html)

With new observations, the scientists confirmed experimentally what existing climate models had anticipated theoretically. The research team used novel data from the Atmospheric Infrared Sounder (AIRS) on NASA’s Aqua satellite to measure precisely the humidity throughout the lowest 10 miles of the atmosphere. That information was combined with global observations of shifts in temperature, allowing researchers to build a comprehensive picture of the interplay between water vapor, carbon dioxide, and other atmosphere warming gases.

Oxides of nitrogen

The main oxides of nitrogen are Nitric Oxide (NO), Nitrogen Dioxide (NO2) and Nitrous Oxide (N2O). Nitrous Oxide occurs in much smaller amount than other two, but it is of interest as it is a powerful greenhouse gas and thus contributes to global warming.

The major human activity, which generates oxides of nitrogen, is fuel combustion especially in motor vehicles. Oxides of nitrogen form in the air when fuel is burnt at high temperatures. This is mostly in the form of nitric oxide with usually less than 10% as nitrogen dioxide. Once emitted nitric oxide combines with oxygen oxidizes to form nitrogen dioxide especially in warm sunny conditions.

These oxides of nitrogen may remain in the atmosphere for several and during this time chemical process may generate nitric acid, nitrates and nitrites as particles. These oxides of nitrogen play a major role in the chemical reactions that generate photochemical smog (Bhandari, 2006).

Risk of climate change in the context of south Asia

Shrestha N.B (2011) in his thesis as mentioned about the risk of climate change in the context of south Asia. According to him “ Asia comprises all four types of climatic conditions – Boral, aerial, tropical, temperate so that this region has been encountered threats of social, economic, risk of resources and environmental and natural calamities. Therefore, condition of natural disasters have being devasted due to decrease in quality of water and air, ever increasing use of natural resources and increase in amount of the pollutants produced by its use, and problems in ecosystem. Detrimental effects from the natural calamities in this continent are quite more in compare to others. Disasters like Tsunami hurricane in Indian Ocean (2004), earthquake in Pakistan (2005), landslide in Philippines (2006) are prominent examples of the region. Besides these, due to the climate change natural disasters – different seasonal events, hurricane, drought, downpour, avalanche, lightening, thunders etc. have been occurs that caused huge loss of life and property.

Moreover, vector borne diseases like Malaria, Dengue and Encephalitis are being epidemic that are caused by climate change. Above different causes are responsible for increasing natural disasters by three times within last 30 years. Forest has played a significant role reducing greenhouse gases emission through carbon sequestration (UNEP, 2007).

A rise in the amount of degraded land and the spread of desertification – “the most critical challenges" in South Asia - are having profound economic and environmental impacts on the region, the UNEP report on the region states. South Asia is suffering from an increase in water demand, overexploitation of groundwater resources and deteriorating water quality, as well as unsustainable patterns of consumption that threaten the region's ability to secure its sources of food, water and energy.

“The scarcity of the region's renewable water resources also poses a major challenge in the region, denting West Asia's ability to produce enough food to meet the growing population's needs. High population growth and rolling conflicts mean that the carrying capacity of the land has become too low to support people with freshwater and food”, the report says.

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