UNIT 8: CLIMATE CHANGE
UNIT 8: CLIMATE CHANGE
Key unit competence:
By the end of this unit, I should be able to discuss climate change and its impact on
Rwanda and other countries.
Introductory activity
1. Make a research on internet and other geographical materials to
establish a relationship between the following concepts:
i. Climate change
ii. Global warming
iii. Green house phenomena
iv. Desertification
2. Basing on the knowledge acquired in the first question assess the
consequences of climate change in Rwanda.
3. Which area of Rwanda is likely to experience the desertification? Givereasons supporting your answer.
8.1 Climate change: definition, causes and effects
8.1.1 Definition of climate change
Climate change refers to the long-term changes in average conditions and
characteristics of earth’s lower surface atmosphere resulting either from natural
variability or human activities that change atmospheric conditions of a region
or location. It is also defined as a long term change of climatic elements such as
temperature, rainfall, wind speed and direction, sunshine, atmospheric humidity,
atmospheric pressure, cloud cover over a given region of earth’s lower surface
atmosphere or globally.
8.1.2. Causes of climate change
The causes of climate change are classified into natural causes and man - made
causes.
i. Natural causes of climate change
Natural causes of climate change include:
• Variations in the earth’s orbital characteristics
The more elliptical orbit makes the earth to be once year in closest position to the
sun (Perihelion: 147 500 000 km) or in farthest position to the sun (Aphelion: 152
500 000 km). At the Aphelion, the earth receives the least solar energy while the
maximum is received at the Perihelion.
i. Volcanic eruptions
Volcanic activity affects the climate. World temperatures are lowered after a series
of volcanic eruptions. This is due to the increase in dust particles in the lower
atmosphere which will absorb and scatter more of the incoming radiation. Sulphur
dioxide gas is given off during some of the eruptions. This gas remains in the
atmosphere for as long as three years and it reacts with water vapor and forms a
bright layer in atmosphere. This layer reduces the amount of solar radiation reaching
the earth surface by reflecting some back to universe.
• Variations in solar output
Sunspot activity which occurs in cycles, may significantly affect our climate. Times
of high annual temperatures on earth appear to correspond to periods of maximum
sunspot activity. The results found from satellites measurements showed a decrease
of 0.1% of the total solar energy coming to the earth in the early 1980s. This value was
obtained over a period of 18 months. It is predicted that the increase in solar output
of 1% per century will contribute to the increase of the global average temperatures
by between 0.50
C and 10C.
• Variation of aerosols in atmosphere
Aerosols like solid particles of varying sizes and liquid droplets which include:
ploughed soil cover, deserts, rocks, salt particles from seas and oceans; meteoric
particles, organic matter, such as bacteria, seeds, spores and pollen. These particles
help in selective scattering of shortwave electro-magnetic solar radiation which
adds varied color of red and orange at sunrise and sunset. Some of the aerosols,
mainly water droplets, absorb certain amount of solar radiation while some amount
of radiant solar energy is reflected back to the space. The high concentrations of
aerosols in atmosphere decrease the temperatures to reach the earth surface.
• Sunspots
Sunspots, defined as dark areas within photosphere of the sun and surrounded
by chromosphere, are created in the solar surface (photosphere) due to periodic
disturbances and explosions. These dark areas are cool areas because they are
characterized by 1, 5000C less temperature than remain part of photosphere. The
increase or decrease in number of sunspot is completed in a cycle of 11 years. It
is believed that the energy radiated from the sun increases when the number of
sunspots increases and consequently the amount of insolation received at the
earth’s surface also increases.
ii. Human causes of climate change
Human activities have been the mostly responsible for atmospheric alterations.
Human activities participate highly in atmospheric pollution leading to the change
in composition of atmosphere.
The atmosphere is polluted by human activities in the following ways:
• Variations of carbon dioxide in atmosphere
Carbon dioxide (CO2) is an important heat-trapping (greenhouse) gas. It is released
through human activities such as burning fossil fuels and gases released from
industries, as well as natural processes such as respiration and volcanic eruptions.
There is a positive relationship between the concentration of carbon dioxide in
atmosphere and the global temperatures: high concentrations of carbon dioxide
result to the rise of temperature on the earth surface while low concentrations of
carbon dioxide result to the lower temperatures.
• Forest and grassland fire
It increases the concentration of carbon dioxide in atmosphere resulting from the
burn of trees and grassland which are cut and put under fire for different purposes.
• Deforestation and land use changes
When people clear large areas of forests and grasslands for cooking or construction,
they reduce the main disposal system for carbon dioxide from atmosphere by
photosynthesis, which leading to the increase of carbon dioxide, and eventually to
the increase of temperature on the earth surface.
• Industrial developments
Gases like methane, nitrous oxide, chlorine, bromine and fluorine are added into the
atmosphere through industrial activities.
• Industrial waste and landfills
Industries which are involved in cement production, fertilizers, coal mining activities,
oil extraction produce harmful greenhouse gases. Also, landfills filled with garbage
produce carbon dioxide and methane gas contributing significantly to greenhouse
effect.
• Urbanization
The buildings of cities increase the reflection and decrease the absorption of solar
radiation which would change the temperatures on the earth surfaces. The urban
activities participate also in increasing the concentrations of greenhouse gases in
atmosphere leading to the rise in temperature.
• Increase in Population
It is obvious that the last two decades have experienced huge increase in the
population. Now, this has resulted in increased demand for food, cloth and shelter.
New manufacturing hubs have come up cities and towns that release some harmful
gases into the atmosphere which increases the greenhouse effect. So, more people
means more usage of fossil fuels which in turn has aggravated the problem.
• Farming
Nitrous oxide is one the greenhouse gas that is used in fertilizer and contributes to
greenhouse effect which in turn leads to global warming.
8.1.3 Effects of climate change
i. Effects of climate change in the world
The following are the effects of climate change in different parts of the world:
• Increase in the amount of rainfall: A rise in global temperatures could lead
to an increase of evapotranspiration. This could eventually lead to the rise in
amount of rainfall.
• Melting of glaciers: A rise of temperature leads to the melting of glaciers in
polar and mountainous regions resulting into flooding. This would cause the
levels of the sea to rise by 20 cm by the year 2030.
• Rise in the sea and ocean levels: The increase in the amount of rainfall and
melting of glaciers leads to the increase of the sea and ocean levels destroying
both human and physical features at the coast.
• Increases in intensity of extreme weather: Climate change increases events
such as heat waves, tornadoes and hurricanes.
• The prolonged severe droughts: Some regions may experience prolonged
droughts caused by reduction in rainfall, which may result in aridity.
• Depletion of ozone layer: High amount of harmful ultraviolet radiation
increases the cases of animal and human diseases such as cancers, blindness
and other eye diseases.
• Occurrence of acid rain: Acid rain is harmful to animal and human being.
• Lower crop and timber yields: Since ultraviolet radiation slows down many
aspects of plant growth such as photosynthesis and germination in many
plants leading to low production.
• Reduction of plankton growth: As temperature goes beyond coral reefs
living standard, fish breeding and feeding patterns are disrupted.
• Decrease of agricultural production: In some regions, the rainfall may
decrease, or agriculture seasons be disrupted because of climate change.
Some regions became drier and make soil infertile for crop production.
• City environments becoming warmer: The increase of carbon dioxide makes
the temperatures to increase most in urban areas.
• Water use and long-term planning: A wetter or drier climate can affect water
resources planning. Water reservoirs, dams, and hydroelectric projects might
become useless in coming years.
• Spread of vector-borne diseases: Because of high temperature there can be
an increased range of insects.
• Acidification of oceans: This can create a reduction in plankton, coral reefs
and a drop-in fishing yield.
ii. Effects of climate change in Africa
The following are some of the facts showing the climate change and variability in
Africa:
• Melting of glaciers on the top of the highest African mountains such as
Kilimanjaro, Rwenzori, Mount Kenya, and Kalisimbi.
• Warming in African tropical forests has been evaluated at 0.29 °C for the past
10 years and 0.1 °C to 0.3 °C in South Africa, while it ranged between 0.2 °C and
0.3 °C in the Nile Basin countries.
• Decreasing trends in temperatures; in eastern Africa, the situation has been
complex because they have been observed over the regions close to the coast
or major inland lakes and increasing in the rest of the region.
• The gradual heating, between 1961 and 2000, over the continent meant more
warm spells (days) and fewer cold days across Africa. An increase in temperature
in Sahara desert has led to the decline in volume of water in Lake Chad.
• Fluctuations of precipitation; the extent of variability is complicated and
exhibits more spatial and temporal fluctuations across the continent
The decrease in rainfall has been registered in West Africa (between 4 ° and 20
°North; 20 °West and 40 °East), by up to 20% to 40% for the periods 1931-1960
and 1968-1990 respectively. A similar decline in mean annual rainfall has also
been observed in the tropical rain-forest zone. A reduction of around 4% in
West Africa, 3% in North Congo and 2% in South Congo for the period 1960-
1998.
• Increases in rainfall have been registered in different parts of southern Africa
(e.g., Angola, Namibia, Mozambique, Malawi, and Zambia)
• Increase in the desertification in south of the Sahara desert.
• Links have also been identified between the warm Mediterranean Sea and
abundant rain fall over the surrounding regions.
iii. Effects of climate change in Rwanda
Rwanda experiences some rainfall events that cause unexpected flooding and
catastrophic events such as landslides etc. These extreme events are attributed to
climate change. The figure below represents some effects of extreme rainfall eventsof climate change in Rwanda.
The following are effects of climate change in Rwanda:
• Significant increase in precipitation at a rate of between 2 and 6.5 mm per
year over the Congo-Nile crest and the northern highlands for the period of
1935–1992.
• Floods that occurred in May 2002 caused the death of 108 persons in North
western regions while the one occurred in 2007 have resulted to displacement
of more than 456 families and destruction of hundreds of hectares of crops in
Bigogwe sector in Nyabihu District.
• During September 2008 heavy rainfall accompanied by winds affected 8 of the
12 sectors of Rubavu district and provoked the displacement of more than 500
families, caused the destruction of about 2,000 hectares of crops and many
other infrastructures.
• Floods reported in September 2012 in Nyabihu, Rubavu, Bugesera and Kirehe
districts whereby more than 1000 families were displaced and their crops
submerged completely.
• The landslides and floods caused by heavy rainfall are regulary observed mainly
in north- western parts of Rwanda (Rulindo, Gakenke, Musanze, Nyabihu and
Rubavu districts). For instance, the floods which occurred on 2nd and 3rd April,
2016 caused the death of 12 people, with 19 injured and destruction of 196
houses across the country. The floods which took place in Musanze district
on 20th April 2016, caused the destruction of 64 houses and many hectares of
crops and cattle.
• The significant increase in mean annual temperatures of between 0.036 and
0.066 °C per year for the period of 1961-1991.
• Since 1902, a number of famines following prolonged droughts episodes have
been registered in Rwanda notably in eastern and south-eastern regions.
• More occurrences of lightning combined with the thunderstorms in 2013
caused 12 deaths in Karongi, 12 in Rubavu, 4 in Rusizi and 5 death Rutsiro
districts, respectively. The same districts suffered from the same extremeweather events which were reported to cause 15 deaths in 2015 (JanuaryOctober) with 30 people injured.
Application activity 8.1
1. Explain the common effects of climate that are observable worldwide
and in Rwanda.
2. Identify the areas of Africa that are susceptible to face the climate change
challenges?
3. Describe the effects of climate change in Eastern and Western provinces ofRwanda.
8.2. Global warming and green house phenomena
8.2.1. Definitions of global warming and greenhouse phenomena
These two phenomena of global warming and greenhouse are related but are
different.
• Global warming
Global warming refers to the gradual rise in world temperatures. This is a gradual
increase in the average temperature of the earth›s atmosphere and oceans due to
increase in the amount of carbon dioxide. The increase in the amount of carbon
dioxide leads to greenhouse effect. It is a change that is believed to be permanently
changing the earth’s climate. An increase in greenhouse gases increases the
greenhouse effect which in turn increases the global warming. In the last 100 years,
the mean surface temperature on earth has increased by 0.5 °C.
• Greenhouse effect
The greenhouse effect is a phenomenon in which the atmosphere of a planet traps
radiation emitted by sun. It is caused by gases such as carbon dioxide, water vapor,
and methane that allow incoming solar radiation to pass through but retain heatradiated back from the planet’s surface.
8.2.2 Causes of global warming and green house phenomena
The following are the causes of global warming and green house phenomena:
1. Human factors
Human activities produce various gases ejected in the atmosphere that are
responsible for the global warming. These activities are destroying earth at fast
rate. The emission of carbon dioxide from industries and vehicles, the burning
of fossil fuels, cutting of trees and forests to build some new buildings and new
malls, dumping of trash everywhere and not even recycling it, excessive use of the
plastics and smoke from factories. All the activities performed by human beings are
the major factors for gases that pollute the air and warm up the earth. These may
contribute to the destruction of the ecological balance of the nature leading to the
global warming.
i. Burning of fossil fuels
Fossil fuels are burnt on day-to-day basis. This activity produces large percentage
of gases such as carbon, petroleum, coal and many other different gases which are
emitted in earth’s atmosphere. Carbon dioxide being one of gases with greenhouse
effect is provided in excess in our atmosphere in far greater quantity in comparison
with other gases produced by human activities.
ii. Use of chemical fertilizers
The use of the artificial chemicals for crops has become one reason for the global
warming. These chemicals are dangerous to the earth as well as to the human beings.
These fertilizers are rich in the nitrogen oxide which is more dangerous than
the carbon dioxide. These oxides of the nitrogen destroy ozone layer even faster
than other greenhouse gas and hence lets harmful ultraviolet rays enter atmosphere
thus making earth warm and leading to the global warming.
iii. Industrial advancement
More and more different industries and factories are set up in modern world to
meet needs of the human beings. These factories need large amount of fuels like
some coal, petroleum for power generation and electricity required by machines
to work. Burning of these fuels also releases large amount of the carbon dioxide
which absorbs harmful radiations from sun making it warm, hence increasing global
warming.
iv. Deforestation
The mass removal of trees, called deforestation, also affects the amount of carbon
dioxide in our atmosphere. Forests around the world are being cleared for cultivation,
mining, building, roads building, grazing cattle, etc. As they grow, trees take in carbon
dioxide. When trees are removed, the carbon dioxide that they could have removed
from the atmosphere is left. Cut-down trees are often burned. Burning produces
more carbon dioxide. If the trees are cut, plants will not be able to produce oxygen
and concentration of the carbon dioxide will increase. Increase of the carbon dioxide
in air is very harmful for the human beings and also disturbs water cycle and hence
total imbalance of our ecosystem. So being one of greenhouse gases it will lead to
the global warming.
v. Air pollution
The harmful gases emitted from vehicles and the factories and greenhouse gases
cause some pollution in the air and these gases get captured in atmosphere. The
smoke gather up in atmosphere forming some clouds full of harmful gases which
later fall as the acid rain which destroys plants. Plants provide us with oxygen and
if they die level of carbon dioxide will increase in atmosphere which is known as a
harmful gas. These gases emit heat which increases temperature of earth, hence
causing global warming.
2. Physical factors
i. Volcanic eruptions
Volcanic eruptions are also among the causes of global warming. These eruptions
contain the dust particles and gases like the sulfur dioxide which stays in the
atmosphere for years and blocks the sunlight from reaching surface of earth making
it somewhat cool. These dust particles affect balance of atmosphere and becomes
contributing factor of the global warming.
ii. Depletion of ozone layer
Depletion of ozone layers is an important factor that causes of global warming. The
ozone layer is known as the layer outside the atmosphere which protects surface
of the earth from harmful ultra-violet and the infrared radiations causing some
dangerous diseases like the skin cancer. Ozone layer depletion is one of causes of
the global warming; entering of the harmful gases which helps in heating up the
earth but other greenhouse gases like the carbon dioxide and methane that helps
in heating up and tears up ozone layer making a hole called “Ozone hole”. So, ozone
layer depletes due to these gases which allow ultra violet radiations to enter the
earth’s atmosphere making it more warm than normal and also affects temperature
leading to the global warming.
iii. Impact of greenhouse process on global warming
Greenhouse effect is a process in which the atmosphere of the earth traps some of
the heat coming from the sun and fails to radiate, making earth warming. This is due
to the burning fuels, cutting of trees, concentration of the heat on earth is increased
to some abnormal levels making the greenhouse effect as one of the major causes of
the global warming. Carbon dioxide, nitrous oxide and methane are the greenhouse
gases which help to keep earth warm. It is natural phenomenon that takes place
with adequate concentrations of some greenhouse gases. When concentration of
these gases rises then they disturb climatic conditions, thus making earth warmer.
These gases are not able to escape and that causes the worldwide increase in
temperatures. So balance of the carbon dioxide and some other gases should be
maintained so that it does not become major reason for the global warming.
8.2.3. Effects of global warming and green house phenomena
Effects of global warming and green house phenomena are multiple. Only the most
important are briefly presented below:
i. Increase in temperature
The intense heat waves and rising temperatures are becoming more common as
greenhouse gases are trapped in the atmosphere. The energy from the sun which is
responsible for the earth’s weather and climate is radiated back into space. While this
happens the greenhouse gases (water vapour, carbon dioxide, and other gases) trap
some of the outgoing energy and retaining the heat. The greenhouse effect thus
leads to a rise in temperature on, and as it becomes stronger, more heat is trapped
within the planet.
ii. Melting of ice and rising sea levels
Warm surface temperatures cause glaciers, polar ice shelves and other ice bodies to
completely destabilize and melt. This in turn increases the amount of water in the
world’s oceans thus contributing to a rise in sea levels. Consequently,
some low-lying areas experience increased flooding.
iii. Extinction of some animal species
Warming temperature of water bodies, desertification and deforestation can
all contribute to the irreversible impact on natural habitat and thus threaten
endangerment and even extinction of some plants and animals. As an example; the
polar bear is considered to be an endangered species whose numbers are falling
because of their inability to adapt to the volatile temperature changes in the Polar
Regions.
iv. Migration of animals
All animals live in regions with extremely specific climate and geological conditions,
such as temperature and rainfall patterns, that enable them to survive and reproduce.
Any change in the climate of the specific habitat can affect the animals that exist
there, as well as the overall makeup of the environment. Some species respond to
warmer climatic conditions by migrating to cooler locations. For example, some
North American animals have moved to the farther north of the region or to higher
elevations to meet their requirements.
v. Effects on human health
Changes in weather conditions can lead to health conditions ranging
from heat related heart and respiratory problems to malaria. Droughts, floods and warmer
temperatures combine in order to create an apt habitat for insects and creatures
such as mosquitoes and other disease-carrying agents which causes dangerous
diseases and sometimes leading to the death.
vi. Storms
The phenomenon of global warming is bound to increase the degree of severity in
terms of storms. Warmer temperatures and warmer ocean waters would increase the
intensity of these storms thus leading to a high number of devastating hurricanes.
On observing the pattern of storms in the past decade it can be noted that the
frequency has literally doubled. Along with floods comes loss of lives, damage to
property, resources.
vii. The failure of ecosystem
An increase in greenhouse gases can cause drastic and irreversible changes both
in the upper atmosphere and within the planet thus affecting its every component
including land, water, air, plants and the processes that occur at all these levels. If not
becoming extinct, animals and plants move away to non-native habitats when the
very ecosystems that they were adapted to for survival lose its quality or probably
even disappear.
viii. Economic collapse
The results of climate change have a direct relationship with a nation’s economy.
Natural disasters such as hurricanes and floods as an effect of the global warming
process end up becoming a costly affair for the government in terms of clean-up
costs, property damage and rehabilitation costs.
ix. Droughts
A warmer climate owing to global warming will eventually lead to diminishing
water supplies and pathetic agricultural conditions in turn resulting in crop failures.
If these water shortages are persistent it will cause a lot of disruptions in global food
production by affecting agriculture and is thus causing starvation.
x. Occurrence of wars
Hostilities and conflicts amongst countries are constantly on the rise as nations
are competing and ruthless when it comes to acquiring resources. An important
example of this is the conflict in the Darfur region situated in Sudan or the Somalian
war with roots in the reduction of its natural resources due to the sole reasons of
climate change. It is clear that the increasing number of wars that commence on
the foundation of food and water scarcities may lead to uncontrollable levels ofaggression, insecurity and regional instability.
Application activity 8.2
1. Explain why causes of climate change and green house differ in rural and
urban areas.
2. Among the effects of climate mentioned above, which ones do you
observe in your local environment?
3. Referring to the greenhouse phenomenon, describe the advantages and
disadvantages of the farming practiced in greenhouse
8.3 Adaptation and mitigation measures for climate change
Learning activity 8.3
In your local environment, identify any evidence of climate change and propose
sustainable strategies to deal with it.
8.3.1 Adaptation measures for the climate change
Adaptation for climate change refers to measures and strategies taken to cope with
climate change and variability. These measures vary from one domain to the other
like agriculture, livestock keeping, tourism, public health and water management;
from one climatic region to the other as dry, wet, hilly, flat, depression, mountains,
floodplains; from season to season as in dry and wet seasons; and across diverse
actors as private, public, national, international, NGOs, local communities. Hence,
adaptation measures are many and are not homogeneous.
The following are some of them:
• Maintaining current ecosystems wherever possible: This implies
strengthening, extending and in some cases refining global protected area
networks to focus on maintaining large blocks of intact habitat with a particular
emphasis on climate change.
• Agro-forestry: This is a land-use system that incorporates trees in food crop
fields. In other words, it is a combination of agriculture and forestry for more
diverse, profitable, productive and sustainable land use.
• Progressive and radical terracing: This is used to reduce runoff, soil erosion
and landslides. At the same time, terracing helps to improve soil quality and
moisture retention, especially in steep areas.
• Soil fertility conservation: Practices like the use of manure, mulching,
planting of leguminous crops help to improve soil fertility by increasing the
micro-organism composition in the soil.
• Seed and grain storage: This involves collecting seeds and grains from
farmers at post-harvesting season and releasing them within the timely agreed
periods.
• The use of pesticides: It is a wide range use of compounds such as insecticides,
fungicides, herbicides, rodenticides, molluscicides, nematicides, plant growth
regulators and others to control pests, insects, fungi, weeds, bacteria, rodents,
all of which are harmful to crops.
• Ecological pest management: This is the use of natural enemy dynamics
or environmental positioning (e.g. crop shading) to eliminate or reduce the
presence of pests.
• The use of improved seeds and species: This is vital to improve crop
productivity.
• Crop varieties and diversification: This consist of integration of different
varieties of crops and hybrids of a particular crop. Multiple cropping aids in
replenishing the soil and maintaining its fertility by ensuring that there is a
constant balance of nutrients by decreasing dependence and saturation of
any one product.
• Land use consolidation programmes: This encourage farmers with adjacent
lands to grow the same crop. This facilitates the provision of inputs (e.g. seeds
and fertilizers), post-harvest activities (e.g. driers, seed and grain storage
facilities) and safer and faster transport of agricultural products.
• Rain water harvesting: It is the practice of collecting and storing rainwater
from rooftops, land surfaces or rock catchment areas for different use.
• Irrigation like drip irrigation is a practice based on the constant application
of specific and controlled quantity of water to the crops. The system uses pipes,
valves and small drippers or emitters that transport water from the sources
(i.e. wells, tanks and reservoirs) to the root area and applying it in controlled
quantities and pressure specifications, while Sprinkler irrigation involves
spraying the crops with water using sprinklers in a manner that resembles
rainfall.
• Wastewater use: It forms a reliable source for crop irrigation and a positive way
to dispose of sewage water. Whereas wastewater contains a lot of nutrients on
the one hand, it carries pollutants like micro and macro organic and inorganic
matters that potentially pose hazards to human health, the environment,
crops and soils, on the other.
• Biotechnology of crops: It involves the practical application of biological
organisms, or their sub-cellular components in agriculture and livestock. The
techniques currently in use include tissue culture, conventional breeding,
molecular marker-assisted breeding and genetic engineering.
• Barrier crops: These are crops that are used as a cultural control strategy
for reducing the spread of pests and diseases to the most vulnerable crops.
These crops provide benefits over “hard infrastructure” in a number of ways:
first, they offer a natural form of protection; second, they contribute to the
biodiversity and often soil improvement; third, they can provide an added
source of food provisions or income and, finally; they can play a determinant
role in soil erosion reduction.
• Integration of meteorological information in agriculture: It is used to
develop early warning systems, crop monitoring and disaster management.
• Training farmers: By offering short courses, seminars and group discussions
on the impacts of climate changes and on various ways of adaptation.
• Facilitating the farmers: By facilitating farmers to access capital that they
need to purchase seeds, installation of tube wells, drilling of pumping sets,
chemical fertilizers, plant protection chemicals, tractors, harvesters, threshers
and other accessories.
• Development of infrastructure: This concerns the improvement of transport
networks, electricity and marketing facilities which use to be affected by
climate change phenomena to promote a sustainable livelihood of population.
• Development of agricultural institutions: The institutions such as universities
provide experts and researchers who offer critical services like assessment,
promotion of agricultural and livestock innovations and dissemination of
research findings to agronomists and farmers at all levels.
8.3.2 Mitigation measures for climate change
Mitigation measures for climate change consist of actions to limit the magnitude
and or the rate of long-term climate change. Climate change mitigation generally
involves reductions in human (anthropogenic) emissions of greenhouse gases.
Anthropogenic greenhouse gases include carbon dioxide (CO2), methane (CH4),
Nitrous oxide (N2O) and a group of gases referred to as halocarbons.
The following are mitigation measures for climate change
• Storing and reducing carbon dioxide: Carbon dioxide can be captured and
stored, but also it can be reduced. Carbon dioxide Capture and Storage (CCS)
is a process consisting of the separation of CO2 from industrial and energy
related sources, transport to a storage location and long-term isolation from
the atmosphere. Conserving electricity is one strategy to reduce CO2. When we
conserve electricity, we reduce the amount of fossil fuel that must be burnt.
One way to save fuel is to change daily activities that rely on energy from
burning fuel.
• Use of energy that reduce the atmospheric pollution: The use of renewable
energy supply technologies, particularly solar, wind, geothermal and biomass
are recommended to reduce the atmospheric pollution. Renewable energy
systems such as hydro-electricity can contribute as well to the security of
energy supply and protection of the environment.
• Reduction of the energy use in buildings: Cooling energy use in buildings
can be reduced by different measures, for example reducing the cooling load
by building shape and orientation. Reducing this energy means, in the case of
using water for cooling, lower water demand.
• Land-use management: Forest land, cropland, grassland, wetlands,
settlements have to be well managed by fighting against any threaten to
them. Changes in land use may result in net changes in carbon stocks and in
different impacts on water resources.
• Cropland management: The use of agricultural practices which promote
the conservation of water, and its quality. There is a need for improved crop
and grazing land management to increase soil carbon storage; restoration of
cultivated peaty soils and degraded lands.
• Afforestation and reforestation: The increase of number of trees helps to
capture the CO2 and decreases the flow of water from catchments.
• Solid waste management and waste water treatment: Controlled landfill
(with or without gas recovery and utilization) controls and reduces greenhouse
gas (GHG) emissions but may have negative impacts on water quality in thecase of improperly managed sites.
Application activity 8.3
1. If you were the Director General of REMA, demonstrate the adaption
measures to climate change in Rwanda.
2. Suppose that you are a manager of a big industrial complex, describe the
strategies to mitigate climate change.
3. Explain the process by which the use of refrigerator contributes to climatechange.
8.4 Climate change and desertification
8.4.1. Definition of desertification
Generally, desertification is described as the turning of the land into desert. It is
the process by which the land undergoes degradation from which a relatively dry
land region becomes increasingly arid, typically losing its bodies of water as well
as vegetation and wildlife. Desertification is caused by a variety of physical factors,
mainly the climate change and human activities.
8.4.2. Causes of desertification
Desertification is caused by a combination of factors that change over time and vary
by location. These include the following:
• Less rainfall (total amount) and increased drought (frequency and intensity).
As a consequence, rivers and water bodies might dry up leading to the decrease
of protective vegetation cove.
• Global warming: It causes higher temperatures and increased
evapotranspiration. This reduces condensation and leads to shortage of
rainfall.
• Population growth: The effect of this is the over-cultivation which reduces
soil fertility and leaves the soil exposed to erosion.
• Deforestation: An increased demand for cultivation land, wood for cooking,
heating, building, increases the risk of soil erosion.
• Poor crop cultivation practices: Some farmers do not know how to use the
land efficiently. Farmers may essentially strip the land of everything that it has
before moving on to another plot of land. By stripping the soil of its nutrients,
desertification becomes more and more of a reality for the area that is being
used for farming.
• Urbanization and other types of land development: Development can
cause people to go through and kill the plant life. It can also cause issues with
the soil due to chemicals and other things that may harm the ground. As areas
become more urbanized, there are less places for plants to grow. This can
contribute to the process of desertification.
• Soil erosion: the losses of the top soils and vegetation leads to the
desertification.
• Climate Change: Climate change plays an important role in desertification.
As the days get warmer and periods of drought become more frequent,
desertification becomes more and more eminent. Unless climate change is
slowed down, huge areas of land will become desert; some of those areas may
even become uninhabitable as time goes on.
• Over exploitation of the land of resources: If an area of land has natural
resources like, oil, or minerals, people will come in and mine it or take it out.
The removal of resources is usually associated with the striping of the soil and
Geography Senior Six Student Book 217
depletion of nutrients. Consequently, plants are died and from there starts the
process toward becoming a desert biome as time goes on.
• Natural disasters: There are some cases where the land gets damaged because
of natural disasters, such as natural fires, drought, floods, and earthquakes.
• Rise of salinity: In the soil which cause the vegetation to be stunted.
• Overgrazing: If there are too many animals that are overgrazing in certain
spots, it is difficult for the plants to grow back. Biomes are affected and lose their original vegetation.
8.4.3 Effects of desertification
The following are the major effects of desertification:
• Farming becomes unproductive: If an area becomes a desert, it’s almost
impossible to grow substantial crops there without special technologies. This
can cost a lot of money to try and do so as many farmers will have to sell their
land and leave the desert areas.
• Hunger (famine): Without farms in these areas, the food that those farms
produce will become much scarcer. The people who live in those local areas
will be a lot more likely to try and deal with hunger problems. Animals will also
go hungry due to food shortage.
• Flooding: Without the plant life in an area, flooding is much more eminent.
Some huge rivers cross deserts which experience a lot of flooding because
there is nothing to stop the water from gathering and going all over the place.
• Poor water quality: If an area becomes a desert, the water quality is going
to become a lot worse than it would have been otherwise. This is because the
plant life plays a significant role in keeping the water clean and clear.
• Overpopulation of the new areas: When areas start to become desert,
animals and people will go to other areas where they can actually thrive. This
causes overcrowding and overpopulation, which will, in the long run, end up
continuing the cycle of desertification that started this whole thing anyway.
• Poverty: All of the issues that are described above (related to the problems of
desertification) can lead to poverty if it is not kept in control. Without food and
water, it becomes harder for people to thrive, and they take a lot of time to try
and get the things that they need for their subsistence.
• Acceleration of desertification: The increased frequency and severity of
droughts resulting from projected climate change is likely to further accelerate
desertification.
• Involuntary migration: Rural population affected by the effects of climate
change, especially the drought or aridity migrate towards different areas. This
may also lead to rural exodus.
• Shortage of drinking water and water to use for other purposes: This is
where overpopulation causes pressure to exploit drylands for farming. These
marginally productive regions are overgrazed, the land is exhausted, andgroundwater is over drafted.
Application activity 8.4.
1. Observe the picture below showing the drought that happened in a dryarea in Rwanda and answer the questions that follow:
i. Referring to the factors of desertification discussed above, describe the
causes of the above phenomenon.
ii. Explain the effects of such phenomenon to the people living in such area.
iii. Considering the physical conditions of Rwanda, suggest the districts in
which the above phenomenon is likely to happen and the strategies to 0782234624limit this problem.
End unit assessment
1. Compare the factors that can cause the climate change in China and
Rwanda.
2. Explain the causes of climate change in developed and developing
countries.
3. The World needs to develop at high rate with its industrialization
processes which is among the most causes of greenhouse effects. Suggest
the mitigation measures for climate change in this regard.
4. The world is facing the problem of climate change and this is substantially
leading to the problem of desertification. Indicate the most affected
areas by that problem? Suggest the sustainable strategies to address theproblem of desertification.