For events lasting two days, the study found projected average intensity increases of 3–8% across the assessed urban agglomerations under the different global warming levels. The reported pattern continued for durations of five and 10 days, indicating that the analysis identified increases in the maximum intensity of multi-day high-temperature extremes across the three warming scenarios. The available findings do not provide separate average estimates for each warming level, so they do not establish a precise progression between 1.5 °C, 2 °C and 3 °C.

Amritsar, Jalandhar, Delhi, Shimla and Kanpur stood out among the locations with larger projected changes. Their increases in intensity ranged from 20–26% under the 1.5 °C global warming level, 22–28% under 2 °C and 26–33% under 3 °C. These are modeled percentage changes in the study’s extreme-event intensity measure; they are not projected numbers of hot days, local temperature records or the timing of individual heat extremes. The results nevertheless show substantial variation among the urban agglomerations included in the analysis.

The study also projected changes in temperature return values for 10-, 20-, 50- and 100-year periods. For two-day events, these values were projected to increase by 3.5–9% across most of the 54 urban agglomerations under the different global warming levels. Amritsar, Jalandhar, Delhi and Shimla showed significant projected increases in return values for durations of two, five and 10 days. The source does not report the city-specific return-value changes or provide enough information to describe changes in the occurrence or frequency of events directly.

To evaluate how duration and intensity are related, the authors used bivariate copula functions and generated temperature–intensity–duration–frequency, or TIDF, curves for eight selected urban agglomerations under each assessed global warming level. These methods enabled the analysis to consider the two dimensions of a high-temperature extreme together rather than treating event length and intensity as separate questions. The supplied source does not name the eight locations used for the TIDF analysis or report their individual curve values. Overall, the study identifies projected increases in multi-day extreme-heat intensity and return values across a broad set of Indian urban agglomerations, while calling for stronger mitigation and for adaptation planning that can support urban planners, policymakers and communities in managing the consequences of extreme temperatures.

Subject of Research: Projected changes in multi-day high-temperature extremes across 54 Indian urban agglomerations under three global warming levels.

Article Title: Projected changes in high-temperature extremes across Indian urban agglomerations under different global warming levels: a bivariate approach

Article References: Maurya, H. K., Gupta, R., Joshi, N., Suryavanshi, S., & Kumar, V. (2026). Projected changes in high-temperature extremes across Indian urban agglomerations under different global warming levels: a bivariate approach. Environmental Science and Pollution Research. https://doi.org/10.1007/s11356-026-38310-w

Image Credits: AI Generated

DOI: 10.1007/s11356-026-38310-w

Keywords: CMIP6, India, urban agglomerations, heat extremes, global warming, bivariate copulas, TIDF curves, temperature return values, climate adaptation, Projected, changes, high-temperature