Impact of global warming on heating and cooling degree days in major Indian cities

[Display omitted] •Assessed the impact of global warming on heating and cooling degree days in India.•Historical and future temperatures and cooling degree days have upward trends.•Historical and future heating degree days usually have downward trends.•Buildings’ cooling requirements increase while heating requirements decrease. Global warming induced rise in ambient temperatures would significantly impact the space heating and cooling (H/C) energy requirements in buildings. This investigation assessed the impact of global warming on space H/C energy requirements in eight major Indian cities covering all of the county’s climate zones. By using historical weather records and general circulation model outputs, we quantified the historical (1969–2017) and future (2018–2100) trends in annual mean temperatures together with heating and cooling degree days (HDDs and CDDs), which are well-known metrics for quantifying buildings’ H/C requirements. The investigation demonstrated that annual temperatures would be higher by 0.1–1.1 °C in the 2020 s, by 0.6–2.8 °C in the 2050 s, and by 1.0–4.6 °C in the 2080 s, depending on the city and the emission scenario. Due to rising temperatures, CDDs would also increase by 2.9–22.9% in the 2020 s, by 8.3–54.1% in the 2050 s, and by 11.89–83.0% in the 2080 s; thus, increasing the cooling requirements by a similar amount. In contrast, HDDs would decrease by 8.1–30.3% in the 2020 s, by 17.6–83.3% in the 2050 s, and by 19.3–97.1% in the 2080 s, thereby reducing the heating requirements.