Climate Change Shrinking Weather Forecast Window: IMD Chief

Somewhat accurate forecast is essential not only for the agriculture sector but the broader economy and lives of the people.

Sample this: The severe heatwave in Europe has led to aboout 10,000 deaths reports suggest. 

Climate change has undoubtedly raised the risks of sudden flooding and droughts while increasing temperatures. 

But the climate change risks stretch beyond the obvious. It has not only led to uncertainty in weather patterns; what is worrisome is this: It has made weather forecasting exercises difficult for policymakers, and this poses an additional challenge for the country’s growth story.

In an exclusive interview with The Secretariat, Mrutyunjaya Mohapatra, Director General of Meteorology, India Meteorological Department (IMD), said that severe weather events are becoming increasingly “hyper-local”, reducing the window available for accurate forecasting.

“A heavy rainfall event that could earlier be predicted three days in advance may now be forecast accurately only about one-and-a-half days ahead. As weather systems become more erratic and localised, meteorological agencies have to upgrade observation networks, computing capacity and forecasting models to keep pace with a climate that is changing faster than ever before,” Mohapatra said.

He underlined the need to expand the dissemination of information and data.

“Not only IMD, but every sector should also have a decision support system. There should be a continuous data flow from IMD towards their decision support system so that the warning can go out promptly if you have very limited time. So, a warning can be issued one and a half days in advance instead of three days in advance. In such a situation, the early action should be in place,” he said.

Rising temperatures are increasing the frequency and intensity of heatwaves, heavy rainfall events, thunderstorms and lightning strikes, while also making these events more localised and short-lived.

Observing that El Niño remains the most closely watched climate signal for India’s monsoon, Mohapatra said around 60% of El Niño years have resulted in below-normal or deficient monsoon rainfall, but the remaining 40% have recorded normal or even above-normal rainfall because factors such as the Indian Ocean Dipole also shape the monsoon.

“Rising temperatures increase the atmosphere’s moisture-holding capacity, resulting in more intense rainfall events even during El Niño years that are otherwise associated with weaker monsoons,” he said.

El Niño And Its Impact On The Indian Economy

Mohapatra said that a weak El Niño condition has been prevailing over the equatorial Pacific, and rainfall will remain moderate in July and in August. But towards the end of September, El Niño conditions could become more severe.

He underlined that June experienced a 40% deficiency in rainfall. What has come as a relief is that until now, July rains have been satisfactory, and the overall deficiency is about 14%.

“El Niño is an evolving process. It is monitored continuously. India is one of the leading centres for monitoring El Niño and Indian Ocean Dipoles, and our information also goes to the World Meteorological Organisation. We also monitor the prediction by various centres. There is a consensus that El Niño will gradually intensify as we move across the monsoon season,” the IMD chief added.

According to IMD, El Niño does not mean that the entire country would get affected. “This year we have said that east central India, like Chhattisgarh, Odisha, then Andhra Pradesh, Telangana, parts of Tamil Nadu, will get normal or above normal rainfall activity. So some parts of the northeast states will also get normal or above-normal rainfall activity. So El Niño has got various impacts in different parts of the country,” he said.

He, however, pointed out that climate change has little correlation with El Niño. Climate change primarily leads to a rise in temperature. “So you’ve got a higher temperature. El Niño also leads to an increase in temperature. So, therefore, you have the combined impact of El Niño and climate change as a background with the higher temperature,” he added.  

He said it is seen that with a rise in temperature by 1 degree Celsius, relative humidity increases by about 7%.

With this, the water-holding capacity increases, leading to more discomfort or heatwave impact will be more.

IMD To Rely More On AI

The IMD has started to extensively use artificial intelligence to augment accuracy.

“We have got the concept of dual engine; you will have the conventional numerical models run by IMD, but along with this, we also have the AI models developed by other related ministries. So the combined mechanism will improve the forecast patterns. These initiatives will address the gap areas,” he said. 

A host of private sector forecasting agencies have sprung up in India. However, Mohapatra said that the IMD prediction is the official forecast. “Globally, if you look at early warnings, it is the prerogative of the nodal agency of the country. Early warnings should not be provided by any other agency,” he said, adding that it could lead to confusion and even prove harmful for people. 

The Centre has launched “Mission Mausam” to enhance the accuracy and timeliness of weather forecasting, including early warning systems. The mission, which is being implemented by the Ministry of Earth Sciences through its institutions, including IMD among others, is expected to make the numerical weather prediction models more precise. A sum of ₹2000 crore has already been earmarked for the same. “A proposal to augment the mission further up to 2030 in this next financial cycle is under consideration,” Mohapatra said.