Buildings


Some aspects of improved well-being (e.g. health, water, sanitation and energy access) can be linked to building design and technology. Yet developmental challenges have to be seen in a broader context and go beyond the construction of housing to consider social and economic inclusion and the link to other urban activities (see Cities chapter). The poverty relevance of green buildings in this context is closely linked to the impacts of electrification programmes (see discussion in the Energy chapter) as well as the impacts of city structure and transport systems on poverty (see Transport and Cities chapters).


Energy and environmental challenges Whether existing building stock or projected growth of building stock, this sector is already the single- largest contributor to global greenhouse gas emissions. Approximately one-third of global energy end-use takes place within buildings (IEA 2010a). Nearly 60 per cent of the world’s electricity is consumed in residential and commercial buildings, although this usage varies widely according to geographical


location, climate


and consumption patterns (IEA 2009b). For developed countries located in cooler regions of the world, space heating, on average, represents 60 per cent of residential energy consumption, followed by water heating at 18 per cent (UNEP SBCI 2007a).


Projections for 2030 based on IPCC scenarios suggest CO2


summarises these projections for CO2


emissions from buildings will continue to account for around one-third of total CO2


countries from poorly combusted solid fuels combined with poor ventilation is a major cause of serious illness and premature death. Lung infections such as pneumonia and tuberculosis linked to indoor pollution are estimated to cause about 11 per cent of all human deaths globally each year (UNEP SBCI 2010b). The WHO (2009) estimates that every year about 1.3 million people (mostly women and children) die prematurely owing to indoor air pollution from biomass. Estimates by the WHO (2009) further attribute 76 per cent of all lung cancer deaths to the indoor use of solid fuels.


Apart from energy use and emissions, the building sector is responsible for more than a third of global resource consumption annually, including 12 per cent of all fresh water use. The manufacture of building materials consumes about 10 per cent of the global energy supply. Building construction and demolition waste contributes about 40 per cent of solid waste streams in developed countries, with most waste associated with the demolition phase (UNEP SBCI 2010b).


Data challenges When considering the environmental credentials of buildings, the true measure of their performance only becomes evident with occupation, given the impact of factors such as behaviour (cultural habits, environmental expectations and life-style),


climatic


emissions. Table 1 emissions under


two scenarios (IPCC 2007). In the high-growth scenario, the largest contribution is from developing countries while in the low-growth scenario the largest share is from North America and developing Asia, which includes China and India. If per-capita CO2


emissions are considered,


both scenarios suggest that by 2030 the greater share of emissions will still be from OECD countries.


2.2 Opportunities


GHG emissions are the single most important negative externality from excessive fossil fuel consumption but the burning of fossil fuels also causes other externalities such as air pollution and health problems. Approximately 3 billion people world-wide rely on bio-mass and coal to meet cooking and other energy needs (IPCC 2007). Indoor air pollution in residential buildings in developing


The major opportunities for greening the building sector are the relatively low cost of the process, be it retrofitting or new construction, the availability of technologies, and the green evolution of energy supply and demand. These trends are encouraging the effort to transform the building sector.


High-growth scenario (A1) CO2 emissions (in GtCO2 Largest share from Average annual CO2 emissions growth rate (2004-2030)


Table 1: Projected CO2 Source: IPCC (2007)


)


8.6 → 15.6 (2004) (2030)


Developing Asia, Middle East/North Africa, Latin America, sub-Saharan Africa


2.4% emissions from buildings to 2030 Low-growth scenario (B2)


8.6 → 11.4 (2004) (2030)


North America and developing Asia


1.5%


changes and particularities of the control of technical systems in buildings. The only realistic way to rate the energy efficiency of a building is by measuring how much energy has been consumed during a period of occupation, ideally, a minimum of two years. A dearth of accurate data is hampering our understanding of impacts such as occupation, design and technological components.


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