Super El Nino: The methodology behind '15,800 excess deaths' in India estimate

New Delhi: The University of Chicago's Energy Policy Institute's report that claimed that the 'super El Nino' might cause around 15,800 additional heat-related deaths in India over the next six months, was measured using two components, seasonal temperature forecasts, and temperature-mortality relationships, a co-author of the study said.

Nearly 451,000 additional deaths are projected globally in the next six months due to the prevailing 'super El Nino', compared to a normal year, according to the study released on Wednesday.

Also Read: 'Super' El Nino could bring 4.5 lakh excess deaths


Emily Grover-Kopec, a co-author, told PTI that temperature-mortality relationships were assessed using "one of the most commonly referenced seasonal forecasts" from the European Centre for Medium-Range Weather Forecasts (ECMWF SEAS5).

The recently published report claimed that the climate phenomenon could push global land temperatures 1.2 degrees Celsius above normal in the coming months, resembling the higher temperatures that climate change is projected to deliver in the next 20 years.

"When considering a wide suite of seasonal forecasts that are available, the ECMWF SEAS sits in the middle in terms of the projected temperature anomalies, so this presents a relatively moderate view. We also used temperature-mortality relationships that were peer-reviewed and published in one of the most rigorous economics journals, the Quarterly Journal of Economics in November, 2022," Grover-Kopec, who is also a director at the climate and energy practice at the Rhodium Group, said.

Also Read: Worsening El Nino threatens Asia with drought

She said that the earlier study used the same formula to predict deaths far into the future based on climate models, adding that this time it was used differently for shorter-term seasonal forecasts.

Asked why a specific window of 1996 to 2025 was chosen for the report, she said that the goal was to keep the numbers relevant to how decision-makers currently plan and act, as the projections are meant to inform how resources are used, and when early action is taken to save lives.

"Using a long baseline period of 30 years in climate science is common and often considered best practice. We therefore referenced the most recent 30-year period as our baseline: 1996-2025," Grover-Kopec told PTI.

Speaking about the findings in the report, Abhiyant Tiwari, who leads the climate resilience and health team at Natural Resources Defense Council (NRDC) in India, noted that it is a useful early warning and underlines the call to action.

"The study is a useful early warning, but its mortality estimates should be treated cautiously as model-based projections, with the full methodology yet to undergo peer review. The findings nevertheless underline the call to action," Tiwari said.

He said that India's experience with Heat Action Plans (HAPs) and stronger institutional frameworks offer a foundation to scale sustained preparedness, protect vulnerable communities, and share valuable lessons with the Global South and the wider world.

Meanwhile, Harshal Ramesh Salve, a public health professional and faculty at the All India Institute of Medical Sciences (AIIMS), stressed that the report provides an opportunity to act swiftly with clear intention for mitigation strategies such as implementing HAPs at all levels.

"The report further cements the current knowledge regarding heat impact on human health in the form of mortality and morbidity. As expected, the South Asia region is getting one of the worst estimates of mortality. However, it also provides us an opportunity to act swiftly with clear intention for mitigation strategies such as implementing HAPs at all levels, data driven policy making, and developing data-sharing mechanisms at national and local levels," Salve told PTI.

According to the public health professional, an equity-driven approach focusing on the most vulnerable, such as the elderly, people with comorbidities, children, pregnant women and occupational workers, is essential to tackle the situation.