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 %

Ozone O3 3 – 7 %

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).

2. IPCC (2007). "Chapter 7: Couplings Between Changes in the Climate System and

Biogeochemistry" (PDF). IPCC WG1 AR4 Report. IPCC. p. FAQ 7.1; report page 512; pdf page

14. Retrieved 11 July 2011

3. IPCC Fourth Assessment Report, Table 2.14, Chap. 2, p. 212

4. Karl TR, Trenberth KE (2003). "Modern Global Climate Change". Science 302 (5651): 1719–

23. Bibcode 2003Sci...302.1719K. doi:10.1126/science.1090228. PMID 14657489.

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

1997BAMS...78..197K. doi:10.1175/1520-0477(1997)078<0197:EAGMEB>2.0.CO;2. Archived

from the original on 30 March 2006

6. "Methane's Impacts on Climate Change May Be Twice Previous Estimates". Nasa.gov. 2007-

11-30. Retrieved 2010-10-16.

7. Professor Olutimibo .Ogunsote (1988). Introduction to Building Climatology.

8. Raupach, M.R. et al. (2007). "Global and regional drivers of accelerating CO2 emissions".

Proc. Natl. Acad. Sci. U.S.A. 104 (24): 10288–93. Bibcode 2007PNAS..10410288R.

doi:10.1073/pnas.0700609104. PMC 1876160. PMID 17519334.

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9. Shindell, Drew T. (2005). "An emissions-based view of climate forcing by methane and

tropospheric ozone". Geophysical Research Letters 32: L04803. Bibcode

2005GeoRL..3204803S. doi:10.1029/2004GL021900.

10. www.esrl.noaa.gov/gmd/ccgg/trends/

11. www.ucar.edu/learn/1_3_2_12t.htm

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