APPRAISAL OF BUILDING CHANGES TO CLIMATE VARIABILITY IN ENUGU URBAN AREA

1.1Background to the Study

Climate change is a major global phenomenon, which is evidenced by alterations in rainfall distribution, rising of glacier, ocean water expansion, drought, and increased temperature, (Intergovernmental Panel on Climate Change (IPCC), 2013). According to the World Meteorological Organization, climate change is determined based on average values of the weather variables over a period of at least 30 years (Anuforom, 2016).

Climate change is defined as a change in the state of the climate that can be identified by changes in the mean and /or the variability of its properties, which persists for an extended period typically decades or longer (IPCC, 2007). They further stated that the time taken to ascertain these changes varies as well as the level of deviation from the normal. Also, the impacts it has on the ecology.

Buildings are constructed to keep people away from the harmful effects of climate and weather. The effects of changes in climate usually make the internal environment uncomfortable and harsh. The changes in the climate parameters include: increase in temperature, strong wind and precipitation. As the climate changes there is a danger that current building designs will not be suitable for the new climate. However, it is likely that these effects would have to be rapid and severe to require substantial modification of existing buildings (Camilleri, 2000).

Climate change has different degrees of impact on the building systems. It affects the energy demands of the system in several ways. Climate change determines the energy demand of a building (Jenkins, Sandhya, Patidar and Simpson, 2015). Secular variations in climate occurring over a period of 100 to 150 years may not qualify as a climate change if conditions will quickly reverse later, but a change in climate usually takes place over a long period of time of at least 150 years with clear and permanent impacts on the ecosystem (Ayoade, 2003).

The possibility that the climate could be changing was first identified as far back as the 1960s, and the battle against climate change, and its main contributory gas, carbon dioxide (CO2), has continued till now (IPCC, 2007). IPCC (2007) went further to reveal that the physical measurements of global CO2 emissions have been taken since the 1950s. The Mauna Loa

atmospheric CO2 measurements constitute the longest continuous record of atmospheric CO2 concentrations available in the world. The clear upland atmosphere of the Mauna Loa volcano on the Pacific Island of Hawaii is one of the most favorable locations on the planet for measuring undisturbed air because possible local influences of vegetation or human activities on atmospheric CO2 concentrations are minimal and any influences from volcanic vents may be excluded from the records (IPCC, 2007).

The impact of climate change includes: drought, extreme heat waves, storms, tornadoes, floods, loss of life and properties and unusual weather phenomenon are all attributed to climate change and global warming. Due to the rate of climate change, new infrastructure will have to be able to cope with a large range of changing climate conditions, which will make design more difficult and construction more expensive (Hallegatte, 2009).

Nigeria, being a part of the global community is not, therefore, immune to the impacts of climate change. The climate condition of Nigeria is tropical, which basically is influenced by two winds; South-West wet monsoon which blows across the Atlantic ocean and brings with it rainfall and the North-East wind which blows across Sahara desert and brings along; dust, dry season and harmattan (Okereke, 2003).The increasing frequency and intensity of these extreme weather events, and the associated natural disasters, including negative impacts on building design, building materials and the cost of construction and maintenance, are a challenge to mankind.

Enugu Metropolis covers three local government areas; Enugu South LGA, Enugu North LGA, Enugu East LGA and nine principal districts; some of which are; Trans-Ekulu, Uwani, Coal Camp (Ogbete), Achara Layout, New Haven, Ogui etc (Ezenwaji, Nzoiwu and Eduputa, 2016), being in tropics has experienced the impact of climate change heavily. Some of the experiences are flooding, wind storm, erosion, and excessive heat due to increase in temperature among others. Flooding which results after heavy rainfall causes damages at different degrees and in some cases results in building collapse, loss of lives and properties. Most of these affected areas are deserted by the occupants because of imminent consequences of the effects of climate change (Enugu Capital Territory Development Agency (ECTDA, 2013). The sight usually is unpleasant and activities in such area are also disrupted due to the risk posed on human life. The issues of climate change constitute a major threat to socio-economic development programs in every country.

 

The industrial revolution and increase in human activities also have resulted in the emission and accumulation of carbon dioxide, nitrous oxide, methane and other greenhouse gases into the atmosphere. These gases allow solar radiation to penetrate the atmosphere and heat up the earth surface, but prevents the escape of the long wave (thermal) radiation back into space (Anuforom,2016). This is known as greenhouse gas effect, and these gases are known as the greenhouse gases (GHGs). The continuous trapping of excess thermal energy within the atmosphere has resulted in global warming and in turn climate change.

However, concern about the environment and the future of our planet has become the focal point of everyday conversation, political debate and media coverage all over the world (Glavinich, 2008). Extreme weather and climatic events have constituted serious threat to global economic growth over the past few years, especially to the socio-economy of developing nations. In Nigeria, severe floods, windstorms, heat waves and several other extreme weather and climate events have impacted negatively on its socio-economy and many people have been affected physically and psychologically (Nigerian Meteorological Agency (NiMet), 2014 ).

Hence, the (NiMet) is taking far reaching steps in contributing to the mitigation of these harsh weather impacts on the ordinary people, and lending support to the sustainable development of the country. Sustainable development cannot be achieved without having safe and affordable homes which through the centuries have been important aspects of the socio-economic development of humans (Windapo & Rotimi, 2012).

Construction industry is one of the most significant industries that contribute toward socio- economic growth especially to developing countries (Hussin,Rahman & Memon, 2013). In many developing countries, there is also a substantial need for shelter and basic services. Effective policies in those countries can lead to buildings, and wider settlements, that are climate resilient and use energy very efficiently, thus curbing the rise in GHG emissions. Opportunities for major energy savings also exist in the often wasteful and inefficient buildings of developed countries and emerging economies (Patrick, 2014).

The case is not different in the Africa’s urban population which is projected to triple by 2050, increasing by 0.8 billion though many of the continent’s evolving cities are unplanned, with informal settlements of inadequate housing. One of the constraints to understanding the present and predicting the future climate variability is lack of sufficiently dependable observational

climate data in Africa (Osman-Elasha, 2007). A major issue also is the problems of low adaptive capacity in Africa which basically is its low level expertise in the climate science. Cities and towns are highly vulnerable to climate change impacts, typically lacking provisions to cut flood risks or manage floods when they arise. Climate change itself could affect Africa’s rural and urban human settlements, being a determinant of the scale and type of rural-urban migration.

The continent’s urgent adaptation needs stem from its sensitivity and vulnerability to climate change, coupled with poor adaptive capacity. Yet adaptation strategies can generate significant development co-benefits, boosting the chances of their adoption. Softer measures, such as building codes and zone planning, are being implemented. Indeed these consolidate hard and infrastructural climate proofing.

Nevertheless, buildings though affected by climate change, their operation contributes to GHG emissions and contribute significantly to climate change. The knowledge of the relationship between climate change and climate variability with all its parameters is a prerequisite to successful analysis of its impact on building construction and possible design of future resilient building to contain anticipated climate change and its impact. Building construction plays an important role in the sustainability development because it uses the earth’s resources to raise the buildings where people live, work and play (Glavinich, 2008). These resources once tampered, would deplete and in some cases come to extinction, therefore the research analyses the changes in climate that leads to erosion, flooding, draught and other effect as they affect building design, building materials, construction cost, building energy use and maintenance cost.