Research suggests deadly heat stress in northwest India, Delhi to face high thermal discomfort
The thermal stress on Delhi was the highest among metro cities, the study found. Photo: iStock_ Northwest India could face deadly levels of heat stress under a high emission scenario through 2100, according to a new study.
Thermal stress in this region could increase by 0.09 degrees Celsius per decade, 0.26°C per decade and 0.56°C per decade from 2011-2100 under low, middle and high emissions scenarios, respectively, the study published in journal Scientific Reports stated.
The study “highlights the urgent need to evaluate the future implications of such severe heat stress conditions on human health in the northwest India (NWI) region,” the researchers wrote.
Researchers from India collected data on the Universal Thermal Climate Index (UTCI) from 1970 to the present, generated by the independent weather forecaster European Centre for Medium-Range Weather Forecasts.
UTCI, according to the paper, is a thermal index that considers heat transfer between the human body and the environment. It is calculated by combining air temperature, humidity, ventilation and radiation.
They also used models to assess trends in UTCI from 1979 to 2010 and project future thermal stress conditions in India in the near (2022-2059) and far future (2060-2100) under the three different emission scenarios.
The researchers observed that UTCI increased over NWI after 2000. From 2000-2015, the region experienced extreme heatwave events.
Two different models showed that the UTCI increased over the NWI by 0.19 °C per decade and 0.28 °C per decade, compared to the entire India’s increase of 0.08 °C per decade and 0.21 °C per decade.
As for near-future projections from 2011 to 2040, the UTCI trend is 0.23 °C per decade, 0.24 °C per decade and 0.43°C per decade under low, middle and high emission scenarios, respectively.
From 2041-2070, the trend is 0.05 °C per decade, 0.24 °C per decade and 0.55 °C per decade under low, middle and high emission scenarios.
In the far future, from 2071-2100, the trend is -0.05°C per decade, 0.13°C per decade and 0.68°C per decade under the three different emission scenarios.
The Indo-Gangetic plain and central India region may face strong thermal stress during the summer, the paper highlighted.
Further, the researchers also saw an increase in the number of thermal stress days. It gradually increases from 458 days to 619 days to 925 days under low, middle and high emission scenarios in the near future.
There is a two- or three-fold increase in very strong thermal stress days from the near future to the far future across all future scenarios, the researchers said.
The researchers also looked at thermal stress in four cities: Delhi, Kolkata, Mumbai and Chennai.
Urban areas are hotter than the surrounding rural areas as cities are known for energy-intensity activities, trapping heat due to taller concrete structures and a lack of vegetation cover.
They found that Delhi experiences the highest UTCI trends compared to other cities.
“The population in New Delhi experiences more thermal discomfort during the hot summer season,” the researchers wrote in their study.
We are a voice to you; you have been a support to us. Together we build journalism that is independent, credible and fearless. You can further help us by making a donation. This will mean a lot for our ability to bring you news, perspectives and analysis from the ground so that we can make change together.
.png)
Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.