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IMD: Average temperature rising across seasons since 1991
The temperature rising trend is more evenly pronounced during monsoon (June to September) and post-monsoon (October to December) seasons.
New Delhi: Average temperatures across seasons have seen a sharp upward trend in the country since 1991, according to the India Meteorological Department (IMD). The trend is in comparison to the average surface air temperature baseline recorded between 1981 and 2010.
“The excess heat is increasing the moisture holding capacity of atmosphere during these seasons, leading to a spike in heavy and extremely heavy rainfall events,” M Mohapatra, director general of IMD, said on Wednesday.
The temperature rising trend is more evenly pronounced during monsoon (June to September) and post-monsoon (October to December) seasons. “There is also a rising trend in both minimum and maximum temperatures, but the rise is significant in case of the latter,” according to IMD data shared by Mohapatra during the Anil Agarwal Dialogue 2022, organised by the Centre for Science and Environment.
“There is a rise of 0.26 degree C in average minimum temperatures over the country 1901 onwards, but a rise of 0.99 degree C in average maximum temperatures over the same period,” the data suggest.
Heat waves associated with abnormally high temperatures over certain areas, which could also be fatal to both humans and animals, are also on a rise across the country, while there is a declining trend in the occurrence of cold waves.
“With global warming, we are seeing a significant rising trend in heat waves over west central India, including Punjab, Haryana, Rajasthan, Gujarat, Madhya Pradesh and Maharashtra and some parts of eastern India like Jharkhand, Odisha and Gangetic West Bengal and parts of Uttar Pradesh,” Mohapatra said during a session on climate change.
“There is a decreasing trend of cold wave occurrences over northwest India, Indo Gangetic plains and a rising trend of cold waves over some parts of Peninsular India. Variability in weather patterns is also increasing,” he added.
Rainfall in the winter season has gone down gradually but no overall trend as such has been witnessed during the monsoon months in the past few decades. “In day-to-day variation, heavy rainfall days are increasing,” he said.
Rainstorm events associated with floods are also increasing. “Our data shows the frequency of floods and droughts, especially the aerial extent of drought, is showing a rising trend,” he added.
Mohapatra said though the frequency of cyclones has not increased globally, the number of severe cyclones is going up. “In India, too, there is an increase in frequency of extremely severe cyclonic storms over Arabian Sea but no such trend is seen over Bay of Bengal,” he said.
Landfall of category 3, 4 and 5 cyclones (118 kmph to over 200 kmph wind speed) has increased globally while there is a downward trend in the speed of cyclones crossing a coast (low translation speed). “More cyclones form over Bay of Bengal, which is also seeing a decrease in translation speed. This can have a more damaging impact on the coast because if the intensity is not high the cyclone moves slowly,” Mohapatra said, adding that the life span of Arabian Sea cyclones is increasing and so is the accumulated cyclone energy over the north Indian Ocean.
At least half of the world’s population lives in regions vulnerable to the climate crisis, which has become complex, with several interacting factors likely to increase food prices, reduce household incomes, and lead to malnutrition and climate-related deaths, especially in tropical regions, according the Intergovernmental Panel on Climate Change’s (IPCC) latest report that was released on Monday.
“South Asia, including India, is among the most vulnerable, with the Ganga basin likely to face severe water shortage by 2050, Mumbai at high risk from flooding and sea-level rise, and Ahmedabad at danger from the so-called urban heat island effect,” the report has warned.
Deaths related to circulatory, respiratory, diabetic and infectious diseases, as well as infant mortality are on the rise in Asia with high temperatures, the Asia factsheet of the report said. A spike in heavy rain events and temperature will increase the risk of diarrheal diseases, dengue fever and malaria in tropical and sub-tropical Asia. More frequent hot days and intense heat-waves will also increase heat-related deaths in Asia, it added.
Experts, meanwhile, pointed at the need for an immediate, integrated, and transformational climate action to reduce the risks.
“During the last two years, Covid-19 was a deterrent in terms of climate action and adaptation across the globe and in India. Now, the ongoing Russia-Ukraine war could be another diversion that slows down climate action. South Asia, particularly India, is highly vulnerable to climate change, and we need immediate, integrated, and transformational climate action to reduce the risks since our adaptive capacity is now pushed beyond its limits,” said Roxy Mathew Koll, climate scientist at Indian Institute of Tropical Meteorology.
“We will need a transformational climate action that cuts across sectors and regions to reduce huge economic losses and damage to lives and biodiversity. A transformational climate action would require political will and administrative implementation at all levels, from panchayats, districts to state and national levels,” Koll added.
