As is true in many regions, India experiences surface Urban Heat Island (UHI) effect that is well understood, but the causes of the more recently discovered Urban Cool Island (UCI) effect remain poorly constrained. This raises questions about our fundamental understanding of the drivers of rural-urban environmental gradients and hinders development of effective strategies for mitigation and adaptation to projected heat stress increases in rapidly urbanizing India. Here we show that more than 60% of Indian urban areas are observed to experience a day-time UCI.
Heatwaves with large impacts have increased in the recent past and will continue to increase under future warming. However, the implication for population exposure to severe heatwaves remains unexplored. Here, we characterize maximum potential human exposure (without passive/active reduction measures) to severe heatwaves in India. We show that if the global mean temperature is limited to 2.0ºC above pre-industrial conditions, the frequency of severe heatwaves will rise by 30-times the current climate by the end -21st century.
Drought characteristics for the Indian monsoon region are analyzed using two different datasets and standard precipitation index (SPI), standardized precipitation-evapotranspiration index (SPEI), Gaussian mixture model-based drought index (GMM-DI), and hidden Markov model-based drought index (HMM-DI) for the period 1901–2004. Drought trends and variability were analyzed for three epochs: 1901–1935, 1936–1971 and 1972–2004.
Madhya Pradesh is likely to see 1-1.2 degree Celsius rise in temperature by 2045, bringing more droughts that will pose “enormous” pressure on agriculture, water resources, infrastructure and energy sectors, according to a study.
Under a worst case scenario in the long run, urban areas of Delhi, Ahmedabad, Bangalore, Mumbai and Kolkata are projected to experience the highest absolute increases in the heat related mortality by 2080s, says a study by the Indian Institute of Management, Ahmedabad (IIM-A).
Climate extremes have profound implications for urban infrastructure and human society, but studies of observed changes in climate extremes over the global urban areas are few, even though more than half of the global population now resides in urban areas. Here, using observed station data for 217 urban areas across the globe, we show that these urban areas have experienced significant increases (p-value <0.05) in the number of heat waves during the period 1973–2012, while the frequency of cold waves has declined.
A presentation by Vimal Mishra, Haider Ali, D S Pai at the 4th National Research Conference on Climate Change, Indian Institute of Technology, Madras, October 26-27, 2013.
