Editing IPCC:AR6/WGIII/Chapter-2 (section)

==== 2.4.2.3 Buildings Sector ====

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Global direct and indirect GHG emissions from the buildings sector reached 9.7 GtCO 2 -eq in 2019, or 16% of global emissions). Most of these emissions (66%, or 6.4 GtCO 2 -eq) were upstream emissions from power generation and commercial heat (Figure 2.19). The remaining 33% (3.3 GtCO 2 -eq) of emissions were directly produced in buildings, for instance by gas and coal boilers, and cooking and lighting devices that burn kerosene, biomass, and other fuels (Lamb et al. 2021). Residential buildings accounted for the majority of this sector’s emissions (64%, 6.3 GtCO 2 -eq, including both direct and indirect emissions), followed by non-residential buildings (35%, 3.5 GtCO 2 -eq) ( ''high confidence'' ).

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[[File:7de478fa2c86c00402dd31b7a3bcd8df IPCC_AR6_WGIII_Figure_2_19.png]]

'''Figure 2.19''' '''|''' '''Trends and drivers of global buildings sector emissions (see Figure 2.16 caption for details) with energy measured as total final energy consumption.'''

Global buildings sector GHG emissions increased by 0.7% yr –1 between 2010 and 2019 (Figure 2.19), growing the most in absolute terms in East and South Asia, whereas they declined the most in Europe, mostly due to the expansion of renewables in the energy sector and increased energy efficiency (Lamb et al. 2021). North America has the highest per capita GHG emissions from buildings and the second highest absolute level after East Asia (Figure 2.19).

Rising wealth has been associated with more floor space being required to service growing demand in the retail, office, and hotel sectors ( ''medium evidence'' , ''high agreement'' ) ( [[#Daioglou--2012|Daioglou et al. 2012]] ; [[#Deetman--2020|Deetman et al. 2020]] ). In addition, demographic and social factors have driven a cross-national trend of increasing floor space per capita. As populations age and decrease in fertility, and as individuals seek greater privacy and autonomy, households declined in size, at least before the COVID-19 pandemic ( [[#Ellsworth-Krebs--2020|Ellsworth-Krebs 2020]] ). These factors led to increased floor space per capita, even as populations stabilise. This in turn is a key driver for building sector emissions, because building characteristics such as size and type, rather than occupant behaviour, tend to explain the majority of energy use within dwellings ( [[#Guerra%20Santin--2009|Guerra Santin et al. 2009]] ; [[#Ürge-Vorsatz--2015|Ürge-Vorsatz et al. 2015]] ; [[#Huebner--2017|Huebner and Shipworth 2017]] ) (Chapter 9).

Energy activity levels further drive regional differences. In Eurasia, Europe and North America, thermal demands for space heating dominate building energy use, at 66%, 62% and 48% of residential energy demand, respectively ( [[#IEA--2020a|IEA 2020a]] ). In contrast, cooking has a much higher share of building energy use in regions of the Global South, including China ( [[#Cao--2016|Cao et al. 2016]] ). And, despite temperatures being on average warmer in the Global South, electricity use for cooling is a more prominent factor in the Global North ( [[#Waite--2017|Waite et al. 2017]] ). This situation is changing, however, as rapid income growth and demographic changes in the Global South enable households to heat and cool their homes ( [[#Ürge-Vorsatz--2015|Ürge-Vorsatz et al. 2015]] , 2020).

Steady improvements in building energy intensities across regions can be attributed to baseline improvements in building fabrics, appliance efficiencies, energy prices, and fuel shifts. Many countries have adopted a mix of relevant policies, such as energy labelling, building energy codes, and mandatory energy performance requirements ( [[#Nie--2014|Nie and Kemp 2014]] ; [[#Nejat--2015|Nejat et al. 2015]] ; [[#Economidou--2020|Economidou et al. 2020]] ). Efforts towards building refurbishments and retrofits have also been pursued in several nations, especially for historical buildings in Europe, but evidence suggests that the recent retrofit rates have not made a significant dent on emissions ( [[#Corrado--2016|Corrado and Ballarini 2016]] ). The Chinese central government launched various policies, including command and control, economic incentives, and technology measures, but a big gap remains between the total rate of building green retrofit in the nation and the future retrofit potential (G. [[#Liu--2020a|Liu et al. 2020a]] , 2020b). Still, one major global factor driving down energy intensities has been the global transition from inefficient coal and biomass use in buildings for heating and cooking, towards natural gas and electricity, in part led by concerted policy action in Asian countries ( [[#Ürge-Vorsatz--2015|Ürge-Vorsatz et al. 2015]] ; [[#Kerimray--2017|Kerimray et al. 2017]] ; [[#Thoday--2018|Thoday et al. 2018]] ). As developing countries construct new buildings, there is sizable potential to reduce and use less carbon-intensive building materials and adopt building designs and standards that lower lifecycle buildings energy use and allow for passive comfort. [[IPCC:Wg3:Chapter:Chapter-9|Chapter 9]] describes the mitigation options of the buildings sector.

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