The document discusses the causes of climate change in Ethiopia. It explains that Ethiopia's climate is highly variable and the country is vulnerable to climate impacts due to its reliance on agriculture and natural resources. Long-term trends show rainfall is decreasing in the central highlands, with more negative deviations in the late 20th century. Temperatures are also increasing by about 0.1-0.25°C per decade. Climate models project further temperature increases and rainfall decreases of 1-2°C and 1-2% respectively by 2030-2050.

1. 2. Possible causes of Climate change
2.1 Climate system
•The climate system is defined as the five components
in the geophysical system, the atmosphere and four
others which directly interact with the atmosphere and
which jointly determine the climate of the atmosphere.
•The five components are listed below:
(a) Atmosphere;
(b) Ocean;
(c) Land surface;
(d) Ice and snow surfaces (both land and ocean
areas);and,
(e) Biosphere (both terrestrial and marine).
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2. Figure 3.1 — Schematic view of the components of the global climate system (bold), their
processes and interactions (thin arrows) and some aspects that may change (bold arrows).
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3. 2.2 Possible causes of Climate change
•Climate change is a long-term shift in the climate of a
specific location, region or planet.
•The shift is measured by changes in features associated
with average weather, such as temperature, wind
patterns and precipitation.
• What most people don't know is that a change in the
variability of climate is also considered climate change,
even if average weather conditions remain the same.
•Why does the earth’s climate change?
•Factors that cause climate change can be divided into
two categories. Those related to natural processes and
those related to human activity.
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4. A. Natural Causes of Climate Change:
1. 1. Variations in the Earth's orbital characteristic
2. 2. Volcanic eruptions
3. 3. Variations in solar output
4. 4. Change in composition of atmosphere
5. Continental drift and mountain building
6. Ocean - atmosphere temperature exchange
7. Reflectivity
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5. B. Anthropogenic Causes of Climate Change
1. Green house gas emission
I. carbon dioxide
II. Methane
HI. CFCs
IV. Nitrogen Oxide
V. Water Vapour
2. Industrialization
3. Deforestation
4. Overgrazing
5.Overcultivation
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6. •Climate change can also be caused by human activities,
such as the burning of fossil fuels and the conversion of
land from forestry to agriculture.
•Since the beginning of the Industrial Revolution, these human
influences on the climate system have increased substantially.
•In addition to other environmental impacts, these
activities change the land surface and emit various
substances to the atmosphere.
• These in turn can influence both the amount of incoming energy
and the amount of outgoing energy and can have both warming
and cooling effects on the climate.
• The dominant product of fossil fuel combustion is
carbon dioxide, a greenhouse gas.
•The overall effect of human activities since the Industrial
Revolution has been a warming effect, driven primarily by
emissions of carbon dioxide and other greenhouse gases.
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7. 7
The Greenhouse Effect causes the atmosphere to
retain heat
When sunlight reaches Earth’s surface, it can either be
reflected back into space or absorbed by Earth. Once
absorbed, the planet releases some of the energy back
into the atmosphere as heat (also called infrared
radiation). Greenhouse gases (GHGs) like water vapor
(H2O), carbon dioxide (CO2), and methane (CH4)
absorb energy, slowing or preventing the loss of heat
to space. In this way, GHGs act like a blanket, making
Earth warmer than it would otherwise be. This
process is commonly known as the “greenhouse effect

8.  Is the world getting warmer?
 If so, are the actions of mankind to blame for
earth’s temperature increases?
 What can/should be done about these issues?
2.3 Cause and effects of Global warming

9. WHAT HAVE YOU HEARD?
Climate Change

10. OUR QUESTIONS TODAY
Science of Climate Change
 What are Greenhouse Gases?
 How do they cause warming?
 How are humans affecting the climate?

11. •The science of global warming is based on well-
understood physical principles. There is no scientific
debate about this!
•Due to human activities, there are now 40% more
greenhouse gases in the atmosphere than there were
a few hundred years ago.
•The Earth has already warmed as the consequence
of this, and scientists expect that the next 20 to 100
years the world will warm a lot more!

12. CLIMATE CHANGE-
MEAN ANNUAL GLOBAL TEMPERATURE 1960-2005
12

13. HUMAN-PRODUCED GREENHOUSE GAS LEVELS

14. CONTRIBUTION OF THE MAJOR GREENHOUSE
GASES TO GLOBAL WARMING
55
17
15
5
8
Carbon dioxide
55%
CFCs 17%
Methane 15%
Nitrous oxide
5%
Others 8%

15. U.S.
186.1
European
Union
127.8
Russia
68.4
Ukraine
21.7
Poland
14.4
China
57.6
Japan
31.2
Australia
7.6
India
15.5
Kazakhstan
10.1
South Africa
8.5
Canada
14.9
Mexico
7.8
Trinidad and
Tobago
United
Arab
Emirat
es
Kuwait
Total CO2 emissions
Between 1950-2001 in billions of
tons
US: 4% of world’s total population
25% of the world’s greenhouse gases
China:25% of the world’s population
8.5% of the world’s greenhouse gases (since 1950)

17. Explanation of the causes of global warming

18. Explanation of the effects of global warming in both MEDCs and LEDCs

19. Explanation of the effects of global warming in both MEDCs and LEDCs

20. 20
2.4 The causes of climate variability and
observed trends in Ethiopia
Ethiopia is one of the developing countries, which are
more vulnerable to climate variability and change. Low
level of socio-economic development, inadequate
infrastructure, lack of institutional capacity and a
higher dependency on natural resources base make the
country more vulnerable to climatic factors including
climate variability and extreme climate events.

21. Annual Rainfall Variability in Ethiopia
For the highly rainfall dependent Ethiopian Agriculture
The start and end of the rains
Their patterns of distribution
The length,
Frequency and probability of dry spells in the growing
season are
key elements affecting planning, performance, and
management of
agricultural operations
Because unusual rainfall amounts and
distributions usually lead to poor harvest and/or
complete crop failure
shortage of pasture and animal feeds

22. Long-term Trends of Rainfall and Temperature in Ethiopia
Rainfall analysis for the central highlands of Ethiopia
- extreme variability of rainfall and a general decreasing trend
- positive rainfall deviations from the long-term mean in the first of
the century
- negative deviations in the second half of the 20th century

23. Figure: Departure of long-term summer rainfall from its long-term average in
the central Ethiopian highlands
The positive departures observed during the first half of the 20th century
are highly pronounced in the first three decades
The second half of the 20th century suffered predominantly negative
rainfall deviations, with summer values frequently lower than the long-term
average

24. Recent vulnerability assessment studies predicted decrease in
rainfall over the northern parts of Ethiopia
An investigation with three global climate models also indicated a
risk of more frequent droughts under climate change (Board and
Agrawala, 2000)
There has been a warming trend in temperature over the past 50
years
The average annual minimum temperature
- about 0.25 0C every ten years
average annual maximum temperature
- increasing by about 0.10C every decade
Long-term Trends Continued………………..

25. Climate Change Projections
Simulation of future climate for 2030 and 2050 by
- Canadian Climate Center Model, CCCM
- Geophysical Fluid Dynamics Laboratory Model, GFDL
- United Kingdom Meteorological Office-1989 model,
UKMO- 89
- GFDL-Transient Models
Indicated
In temperature Rainfall
There will be an increase of temperature by 1.0 and 2.0oC
a decrease of rainfall by about 1 and 2% in 2030 and 2050,