INTRODUCTION
The Goldilocks Principle can be summed up neatly as "Venus is too hot, Mars is too cold, and
Earth is just right." The fact that Earth has an average surface temperature comfortably between
the boiling point and freezing point of water, and thus is suitable for our sort of life. Our
moderate temperatures are also the result of having just the right kind of atmosphere. ()
This is almost altered by the burning of the fossil fuel deposits on the planet, through technology
which has increased the concentrations of greenhouse gases in the atmosphere and brought about
changes in weather patterns and climate that are a result of our actions.
Atmospheric scientists first used the term 'greenhouse effect' in the early 1800s. At that time, it
was used to describe the naturally occurring functions of trace gases in the atmosphere and did
not have any negative connotations. It was not until the mid-1950s that the term greenhouse
effect was coupled with concern over climate change. And in recent decades, we often hear
about the greenhouse effect in somewhat negative terms. The negative concerns are related to the
possible impacts of an enhanced greenhouse effect. It is therefore important to remember that
without the greenhouse effect, life on earth as we know it would not be feasible.
The residential building is a place where a lot of time is spent for rest. This rest is attained only
when there is comfort or coziness in the building, in order to achieve this, activities .i.e. cooking,
heating, lighting etc. and mechanical equipment that makes use of fossil fuel are used.
Residential land use and development has been associated with greenhouse gas emissions via
three activities: (1) residential energy use, (2) new construction, and (3) transportation
This paper examines the effects and implications of residential designs in hot climate regions.
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THE HOT AND DRY CLIMATE OF NIGERIA
The hot and dry climate is characterized by a high daily temperature range and low humidity
with discomfort caused by either high or low temperatures, thus the need for cross ventilation for
almost all the month in the year. ()
Unlike, the coastal zones that experience regular rainfall, the hot and dry climate scarcely
experience rainfall but when it rains, it rains with a high intensity which could be disastrous if
the building is not well protected.
This climate is characterized by cold night and hot day, thus the need for thermal storage to
provide heat in the night and cooling of the interior.
Source: National Universities Commission (1977). Standard Guide for Universities.
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Figure 2: Characteristics of the climatic regions in Nigeria according to Nick Hollo / B. J.
Garnier.
DESIGN CHARACTERISTICS
All regions have their own specific designs. This is because of the different climatic condition
that exist .The following are the designs found in hot and dry climate:

Site Planning: Buildings are orientated such that the long axis is placed on the East-West
axis to protect from solar gains. Also, for adequate air movement, they are single banked

Compact courtyard planning: This is used to ensure ventilation during the day and
warmth at night.

Openings: Openings occupy 20 to 35% of the wall, to allow for improved body cooling
but protected from sun and rain penetration.
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
Structural materials: Walls, floors and roofs are heavy with high thermal capacity and a
time lag of over 8 hours.
GREENHOUSE
A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and
emits radiation within the thermal infrared range. This process is the fundamental cause of the
greenhouse effect. (IPCC AR4 SYR, 2008)
The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide,
methane, nitrous oxide, and ozone. In the Solar System, the atmospheres of Venus, Mars, and
Titan also contain gases that cause greenhouse effects. Greenhouse gases greatly affect the
temperature of the Earth; without them, Earth's surface would be on average about 33 °C (59 °F)
colder than at present. (Karl TR, Trenberth KE 2003).
Industrial revolution has brought about the burning of fossil fuels, this has contributed to the
increase in carbon dioxide in the atmosphere from 280ppm to 390ppm, despite the uptake of a
large portion of the emissions through various natural "sinks" involved in the carbon cycle.
Carbon dioxide emissions come from combustion of carbonaceous fuels such as coal, oil, and
natural gas.
GREENHOUSE GASES
Greenhouse gases are those that can absorb and emit infrared radiation. [1] In order, the most
abundant greenhouse gases in Earth's atmosphere are:

Water vapor

Carbon dioxide
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
Methane

Nitrous oxide

Ozone
Atmospheric concentrations of greenhouse gases are determined by the balance between sources
(emissions of the gas from human activities and natural systems) and sinks (the removal of the
gas from the atmosphere by conversion to a different chemical compound (IPCC 2007). The
proportion of an emission (e.g. CO2) remaining in the atmosphere after a specified time is the
"Airborne fraction".
Fig 1: Picture showing the absorption and emission of infrared radiation
Source: www.comet.ucar.edu/
IMPACT OF A GIVEN GAS ON CLIMATE SENSITIVITY
Each gases' contribution to the greenhouse effect is affected by the characteristics of the gas, its
abundance, and any indirect effects it may cause. When these gases are ranked by their direct
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contribution to the greenhouse effect, the most important are: (Kiehl, J. T.; Kevin E. Trenberth
1997).
Gas
Formula
Contribution
(%)
Water vapor
H2O
36 – 72 %
Carbon dioxide
CO2
9 – 26 %
Methane
CH4
4–9%
O3
3–7%
Ozone
ANTHROPOGENIC GREENHOUSE GASES
Over the years, human activity has increased the concentration of carbon dioxide and other
greenhouse gases. The main sources of greenhouse gases due to human activity are:

Burning of fossil fuels and deforestation leading to higher carbon dioxide concentrations
in the air. Land use change (mainly deforestation in the tropics) account for up to one
third of total anthropogenic CO2 emissions.

Use of chlorofluorocarbons (CFCs) in refrigeration systems, and use of CFCs and halons
in fire suppression systems and manufacturing processes.

Agricultural activities, including the use of fertilizers, that lead to higher nitrous oxide
(N2O) concentrations.
The seven sources of CO2 from fossil fuel combustion are (Raupach, M.R. et al. 2007):
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Seven main fossil fuel
Contribution
combustion sources
(%)
Liquid fuels (e.g., gasoline, fuel oil)
36 %
Solid fuels (e.g., coal)
35 %
Gaseous fuels (e.g., natural gas)
20 %
Cement production
3%
Flaring gas industrially and at wells
<1%
Non-fuel hydrocarbons
<1%
"International bunker fuels" of transport
4%
not included in national inventories
GREENHOUSE EFFECT
This is the process by which the earth is been kept warm by greenhouse gases
This is created by the heat energy radiated by the sun and greenhouse gases normally present in
the atmosphere. Sunlight passes through the atmosphere, warming the Earth. In turn, the Earth
radiates this energy back towards space. As it passes through the atmosphere, greenhouse gases
(water vapour, carbon dioxide, methane and nitrous oxide) absorb part of the energy, while the
remainder escapes into space. This means that some of the sun's energy becomes trapped – thus
making the lower part of the atmosphere, and Earth, warmer.
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Picture showing the process of Greenhouse Effect
Source: IPCC 2007
EFFECTS AND IMPLICATIONS OF GREENHOUSE
The increased concentrations of greenhouse gases have led to an increase in the world's average
temperature. This is called the enhanced greenhouse effect.
Carbon levels have increased in the atmosphere as a result of burning large volumes of fossil
fuels that have been trapped underground for millions of years. Millions trees have been cut
down of acres of forest and every tree contains carbon, and as a tree is burned or decomposes,
that carbon is released into the atmosphere. Temperature increases will be extreme in some
places and unnoticeable in others. The gross effect, however, will be a potentially devastating
disruption of weather, rainfall patterns, storms, and sea level rise.
The following are the effects and implications of greenhouse:
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1. Increased thermal discomfort: This is as a result of temperature extreme which makes it very
hot in the
day and very cold at night.
2. Increased maintenance costs on the consumption of energy, water and electric power for the
entire life cycle: Due to increased thermal discomfort, residents are forced to make use of
mechanical means to achieve comfort through the use of fans, heat pumps for heating and
cooling the building, generator etc.
3. An unsafe and unhealthy environment: Greenhouse gases in large quantity are unsafe for man.
They include: carbon released as a result of burning of fossil fuel, fluorinated gases are
chemicals used as refrigerants, for insulation, and for other industrial purposes etc.
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REFERENCES
1. "IPCC AR4 SYR Appendix Glossary" (PDF).
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3. IPCC Fourth Assessment Report, Table 2.14, Chap. 2, p. 212
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5. Kiehl, J. T.; Kevin E. Trenberth (1997). "Earth’s Annual Global Mean Energy Budget" (PDF).
Bulletin of the American Meteorological Society 78 (2): 197–208. Bibcode
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6. "Methane's Impacts on Climate Change May Be Twice Previous Estimates". Nasa.gov. 200711-30. Retrieved 2010-10-16.
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10. www.esrl.noaa.gov/gmd/ccgg/trends/
11. www.ucar.edu/learn/1_3_2_12t.htm
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