Climate Change Made UP Heatwave at Least Two Times More Likely: Climate Index

The fact that these extreme temperatures occurred along with high humidity is unusual and contributed to the severity of the event, researchers at Climate Central said in their analysis.

Kochi: Climate change made the recent heatwave in Uttar Pradesh at least two times more likely, as per the Climate Shift Index, which quantifies the impact of climate change on local weather in real time.

As per reports, the districts of Ballia and Deoria in UP witnessed 150 deaths in five days (from June 14 to June 18), when temperatures ranged around 42°C. While there have been questions about lapses in the implementation of the state’s heat action plan, an official with the state’s disaster management authority told The Wire that “it was too early to say” as data is being obtained from districts regarding implementation.

Links between climate change and temperatures

Climate change – caused by global warming due to increased carbon emissions in the atmosphere – can cause extreme weather events. Heat waves are one of them.

As per the India Meteorological Department (IMD), a heat wave “is a condition of air temperature which becomes fatal to [the] human body when exposed [to it]”. The IMD defines a heat wave as occurring if temperatures depart by 4.5°C to 6.4°C more than normal (above different temperature levels for hills and plains), and a severe heat wave when the temperature rises to more than 6.4°C.

The duration of heatwaves in India increased by about 2.5 days between 1961 and 2021 due to global warming, as per a report released by the IMD on April 26 this year.

Parts of Uttar Pradesh and Bihar are reeling under a heat wave. Per one report, at least 96 people have died in the two states between June 14 and June 18. Another cited 150 deaths in five days (from June 14 to June 18) in Ballia and Deoria districts of Uttar Pradesh alone. Authorities have not officially put it down to the heat wave, but said that those who died were above 60 and suffered from different ailments “which may have aggravated due to the heatwave”.

The heat wave is still ongoing. On June 20, the Union health minister Mansukh Mandaviya chaired a high-level meeting to review the situation, and directed an expert team be sent to UP and Bihar to support them in public health response measures to address heat-related illnesses.

Climate Shift Index

Researchers at Climate Central, a US-based climate research and communications group, found that the three-day extreme heat event over parts of UP from June 14 to June 16 was made at least two times more likely by climate change.

They analysed the Climate Shift Index (CSI), developed by Climate Central, that uses a categorical five-point scale to show how climate change makes daily average temperatures more or less likely around the world.

Currently, the index includes more than 1,000 cities and the online real-time map can also reveal changes across regions around cities.

CSI levels over 1 indicate a clear climate change signal, while levels between 2 and 5 mean that climate change made those temperatures between two and five times more likely. Per the team, the methodology used to calculate the CSI is based on peer-reviewed science.

A CSI of 4 means that the day’s temperature was made at least four times more likely than it would have been without the influence of climate change.

The researchers shared the CSI maps centered for the regions around the cities of Lucknow, Kanpur, Gorakhpur, and Varanasi for these dates with The Wire. These show that the CSI was 3 on June 14 and 15 over some parts of these regions within the state. The CSI decreased to 2 on June 16.

The Climate Shift Index map, centred for Lucknow, Kanpur, Gorakhpur and Varanasi, for the dates of June 14, 15 and 16. The red patch over the region for June 14 and 15 shows that climate change made the high temperatures here at least three times more likely. Credit: Climate Central

The fact that these extreme temperatures occurred along with high humidity is unusual and contributed to the severity of the event, the researchers said in their analysis. In addition to UP, most locations across India experienced significant CSI levels during the same period.

“We see again and again that climate change dramatically increases the frequency and intensity of heat waves, one of the deadliest weather events that exist,” Friederike Otto, a researcher at Imperial College London and co-lead of the World Weather Attribution (WWA), said in a press release. “Our most recent WWA study has shown that this has been recognised in India, but implementation of heat action plans is slow. It needs to be an absolute priority adaptation action everywhere.”

Lapses in heat plan implementation? 

Heat action plans are documents that list preparatory, adaptive and responsive measures for government departments to tackle the heat and its impacts. UP is one of the 18 states to have a state-level heat action plan, per a recent report that analysed 37 heat action plans at the city, district and state levels.

The state developed its heat action plan in 2022. The 2023 Heat Action Plan is being updated with the institutional collaboration of IIPH-Gandhinagar and UNICEF, as per a report.

UP’s standard operating procedure for heat waves identifies heatwave responses, including related preparedness and actions at the district level. It includes operating procedures to undertake these response actions. It also lists the lead and support agencies responsible for heatwave response actions.

Some reports have raised concerns regarding lapses in the implementation of the state’s heat action plan.

A senior official at the State Disaster Management Authority, who did not want to be named, told The Wire that the state’s heat action plan, which was developed in 2022 has been implemented this year and is currently in the “during heat wave” phase. Data is being collected from districts to obtain information regarding its implementation, so it is “too early” to tell if there were any lapses in its implementation during the ongoing heatwave in the state, the official added.

Several stakeholders including the district administrations and health department are also involved in its implementation, the official said.

The combination of extreme heat and humidity during heat waves is particularly dangerous for humans, and even more so in urban contexts where the ‘heat island’ effect can further increase temperatures, said Mariam Zachariah, a researcher at Imperial College London and WWA. “Unless carbon emissions are rapidly reduced, these life-threatening events will become more frequent and intense.”

Rivers dry up, agriculture affected

Meanwhile, as per Bihar’s water resources department, more than 30 rivers in the state have dried up, reported Hindustan Times. Water levels in several others including the Falgu in Jehanabad and Lakhandei in Muzaffarpur are below gauge level due to the prolonged heatwave and delayed monsoon, it said.

Between June 1 and June 20, Bihar recorded an 81% rainfall deficit, getting only 14.4 mm of rainfall as against a normal rainfall of 81.5 mm during this time. The rain deficit and the prolonged heat wave have also affected the sowing of paddy seedlings with just 31% of overall transplantation done so far across nine divisions, officials of the state agriculture department told Hindustan Times.