A global comparison of building decarbonization scenarios by 2050 towards 1.5-2 °C targets

Abstract

Buildings play a key role in the transition to a low-carbon-energy system and in achieving Paris Agreement climate targets. Analyzing potential scenarios for building decarbonization in different socioeconomic contexts is a crucial step to develop national and transnational roadmaps to achieve global emission reduction targets. This study integrates building stock energy models for 32 countries across four continents to create carbon emission mitigation reference scenarios and decarbonization scenarios by 2050, covering 60% of today's global building emissions. These decarbonization pathways are compared to those from global models. Results demonstrate that reference scenarios are in all countries insufficient to achieve substantial decarbonization and lead, in some regions, to significant increases, i.e., China and South America. Decarbonization scenarios lead to substantial carbon reductions within the range projected in the 2 °C scenario but are still insufficient to achieve the decarbonization goals under the 1.5 °C scenario.

Fig. 1. Status quo (Year 2020): median of the gross domestic product (GDP), floor area, heating degree days (HDD) and cooling degree days (CDD), final energy consumption (FEC), and CO₂ emissions by the studied region (Northern and Western (NW) Europe and Southern and Eastern (SE) Europe, and South America) or country (the USA and China).

In this plot, each region is described by the countries within the region. In the case of the USA and China, as they are the only countries within their region modeled in this study, their distributions are taken as the distributions of their administrative divisions.

Fig. 2. Annual FEC and CO₂ emissions in residential and commercial subsectors region-wise (NW and SE Europe, South America) and country-wise (USA and China) in the reference scenario (RS) and decarbonization scenarios (DSs) until 2050, shown as percentages of the corresponding value in 2020.

The gray area shows the range of values between the minimum and maximum from both the RS and DSs across the regions.

Fig. 3. Decarbonisation Scenarios (Year 2050).

Gross domestic product (GDP), floor area, annual total final energy consumption (FEC) and CO₂ emissions per capita and per m² across regions and countries.

Fig. 4. Changes in demands and services from 2020 to 2050 (X-axes: population, floor area, and carbon intensity of final energy consumption (FEC) change.

Y-axes: average building energy demand and CO₂ emissions per capita in the different scenarios by regions and countries). The oval arrow shows the direction of evolution over time, and the oval indicates the value for 2050.