Peter Graham

The number of countries mentioning building sector climate actions in their nationally determined contributions (NDCs) has risen from 131 in 2020 to 168 in 2023. However, the wide variety of ways in which these actions are included and described makes it difficult to determine their contribution to Paris Agreement targets or national climate goals, including energy and the reduction of greenhouse gas (GHG) emission targets. Some countries only briefly mention building sector actions as contributing to energy or industry mitigation goals, while others detail more specific actions and targets. This heterogeneity makes NDCs less transparent and difficult to assess for the mitigation potential of individual and collective commitments on emission reduction and adaptation. This research addresses this gap by applying a modified Delphi method, engaging a panel of global experts (n = 14), to develop a framework of 11 aligned criteria as recommendations for structuring building-related chapters in NDCs. The developed criteria for effective building sector commitments in NDCs include: (1) political commitment; (2) stakeholder engagement; (3) sector-specific targets; (4) ambitious goals; (5) a roadmap; (6) a policy framework; (7) comprehensive actions; (8) coordinating bodies; (9) financing; (10) measurement, reporting, verification, evaluation and data; and (11) education and knowledge-sharing. Practice relevance This study addresses the need for a consensus-driven framework to define and assess effective building sector commitments in NDCs. The resulting framework is valuable to a range of stakeholders. For policymakers, this framework serves as a practical tool for designing transparent, ambitious and actionable NDCs, aligning national and subnational building sector actions with broader climate goals, addressing both mitigation and adaptation. For donors, the framework provides a reliable method to evaluate the viability of building sector commitments, ensuring that key elements such as political commitment and financial backing are in place. Additionally, it offers scholars and advocacy groups a structured approach to evaluate and track climate commitments, promoting greater accountability and driving more effective climate actions within the building sector. The proposed framework also has relevance for UNFCCC Conference of Parties’ (COPs) preparations and negotiations.

This paper reports on modelling outcomes for improvements to building energy performance in Indonesia. Long-term climate effects due to building energy demand and carbon emissions are also considered. The global change assessment model (GCAM) was used to generate the related end-user building energy data, including socioeconomics, for urban areas of Indonesia. As a comprehensive study, the total life cycle of carbon in the building sector and the concept of zero-carbon buildings, including energy efficiency, zero-emissions electricity and fuel-switching options, were considered. Building shell conductance (U-value) of the building envelope, floor area ratio (FAR), air conditioner (AC) efficiency, electrical appliance (APL) efficiency, rooftop photovoltaic (PV) performance and ground source heat pump (GSHP) systems were considered as parameters to mitigate carbon emissions under the operational energy category in the GCAM. Carbon mitigation associated with the cement production process was considered in the raw material category. Urban population and labour productivity in Indonesia were used as base inputs with projected growth rates to 2050 determined from the available literature. Low growth rate ‘LowRate’ and high growth rate ‘HighRate’ were considered as variable inputs for U-value, FAR, AC efficiency, APLs efficiency and PV capacity factor to model emissions mitigation. The energy consumption of the GSHP was compared to the conventional reverse cycle ACs to identify the potential of the GSHP as a fuel-switching option. In the GCAM, the benchmark (base case scenario) data set was generated based on input parameters (urban population and labour productivity rate) only for the residential building sector in Indonesia. Total potential carbon emissions mitigation was found to be 432 Mt CO₂-e for the residential building sector in Indonesia over 2020–2050. It was found that an average of 24% carbon emissions mitigation could be achieved by 2020–2030 and 76% by 2031–2050.

This paper reports modelling outcomes for improvements to building energy performance in Indonesia. Long-term climate effects due to building energy demands including carbon emissions are also considered. The global change assessment model (GCAM) was used to generate the related end-user building energy data, including socioeconomics for urban areas of Indonesia. As a comprehensive study, the total life cycle of carbon in the building sector and the concept of zero-carbon buildings, including energy efficiency, zero-emissions electricity and fuel switching options were considered. Building shell conductance (u-value) of building envelope, floor area ratio (FAR), air conditioner (AC) efficiency, electrical appliances (APLs) efficiency, rooftop photovoltaic (PV) performance and ground source heat pump (GSHP) systems were considered as parameters to mitigate carbon emissions under the operational energy category in GCAM. Carbon mitigation associated with the cement production process was considered in the raw material category. Urban population and labour productivity in Indonesia were used as base inputs with projected growth rates to 2050 determined from available literature. Low growth rate ‘LowRate’ and high growth rate ‘HighRate’ were considered as variable inputs for u-value, FAR, AC efficiency, APLs efficiency, and PV capacity factor to model emissions mitigation. The energy consumption of the GSHP was compared to the conventional reverse cycle ACs to identify the potential of the GSHP as a fuel-switching option. Only base input data were used for cement production process parameters without applying any variable inputs. GCAM base scenarios based on input data only (without modifying variable data) for the residential building sector in Indonesia were considered the benchmark for this study. Total potential carbon emissions mitigation was found to be 432 Mt CO2-e for the residential building sector in Indonesia over 2020-2050. It was found that an average of 24% carbon emissions mitigation could be achieved by 2020-30 and 76% in 2031-2050.

India’s growth of energy demand in the building stock, and efforts to curb it, are placed into an international context by adapting the reporting criteria developed for the Global Alliance on Building & Construction's (GABC) Global Status Report (2017) on buildings and construction. A survey of state and non-state actor climate commitments submitted to the United Nations Framework Convention on Climate Change’s (UNFCCC) Non State Actors Zone for Climate Action (NAZCA) database and recent research on the status of building energy codes and standards globally are also presented. To contribute to a 2°C pathway, India must achieve a 50% reduction in building energy demand and related greenhouse gas (GHG) emissions by 2050. India is taking steps toward this goal through initiatives such as recent upgrades to the Energy Conservation Building Code (ECBC), encouraging green building rating and energy certification, and stimulating markets for low-carbon/high-efficiency technologies. However, despite improvements in building energy intensity, neither the global or the Indian building sectors are currently decarbonizing. The adoption of consistent national energy and GHG emission reduction goals could further align national, subnational and private-sector climate action commitments to facilitate a transition to a low-carbon emissions pathway and contribute to limiting global warming to well below 2°C.