India will be able to provide its own climate model to the Intergovernmental Panel on Climate Change for its next assessment report scheduled to be released in 2022
Shailesh Nayak, scientist and former secretary in India’s Ministry of Earth Sciences (Image by Ajanta Goswami)
With predictions of climate change suggesting an increase in extreme weather events, a rise in deaths by sudden events like thunderstorms and lightning and crop losses of up to 25% due to changing weather and rainfall patterns, there is a pressure on the India’s weather forecasters to make predictions more robust. That was why this year’s Geospatial World Forum, held recently in Hyderabad, focused on the role of geospatial technologies in a scenario of changing climate.
In an exclusive interview, Shailesh Nayak, eminent scientist and former secretary in India’s Ministry of Earth Sciences, spoke to India Climate Dialogue on the sidelines of the forum about government initiatives and challenges ahead in the forecasting arena.
India is a leader in geospatial technology in South Asia. How is it helping the farmers who are bearing the brunt of climate change?
As far as India is concerned, we have a strong satellite programme. We have two INSATs (Indian National Satellite System) for weather predictions and around 30-40 satellites overall. Basically, when it comes to agriculture, whether there is climate change or not, weather plays a crucial role and you need to know when it is going to rain, whether it is going to be cloudy or not, what are the minimum and maximum temperatures and so on. So, these are the things that need to be determined irrespective of climate change. In India we have an extremely good system by which we provide information for specific crop and all weather parameters. Today more than one million farmers are using this.
One should also understand that forecasts are of different types and they are for different purposes. A typical forecast of a monsoon is essentially to help prepare the government to respond to it, for instance, ensuring power supply during a drought year for people to extract groundwater. Then comes a forecast, which is of middle level that gives forecast for the next 2-3 weeks. This one is useful for the farmers so that they can decide what overall planning they need to do. And then a short-term forecast assists farmers in making decisions like when to apply fertilisers and pesticides that are dependent on the rainfall.
Farmers know they how to make use of this information. My experience is they have been doing their forecast traditionally, but their vision is narrow. They often look up to the sky and predict. But we use a global model and bring it down to the regional level. We know that something happening elsewhere can also affect his area. And we disseminate the information for free.
Is accuracy of forecast a big challenge?
No forecast is 100% accurate. Let’s say it is 75-80% accurate. Then many people say that since it is not 100% accurate, farmers cannot use it. But we have talked to farmers and one of them gave me a very interesting answer. He said that even without the forecast, his chance of being right is 50%. And with the forecast, his chance of being right becomes 75-80%. So, that’s why a large number of people use it, though no forecast will be 100% accurate.
Now coming to climate change, an individual farmer cannot do much. Let’s say there could be less rainfall. Then he might have to sow twice. But what will he do if seeds are not available? So, what the government needs to do in that case is to keep more seeds in stock. And in any case, we are not able to give that kind of forecast. The climate models are not able to give that kind of short-term forecast.
Do we have enough weather forecast stations and early warning systems?
We don’t need that many stations. If we use a satellite, I have for India more than three billion observations because each pixel gives me information, while we do the actual measurement with 4,000-5,000 stations, which is good enough. You may need a station when you want to do a certain local thing like crop insurance in a particular village. But for us we don’t need it at that level to make a forecast.
As for early warning systems, we are giving very good forecasts for cyclones or heavy rainfall. But what we are not able to predict is sudden onset of thunderstorms or cloud bursts as that technology is still in the making. Like in Bengal you have kaal baisaakhi (spring storms). It comes suddenly and covers a very small region. The whole process of generation and dissipation takes a very short time. You need some observations to understand that process, and that is where we don’t have sufficient technology. Nowhere in the world are these kinds of storms being predicted. We are doing far better prediction of cyclones than the US.
Tell us about some interesting programmes that the government is taking up in the area of climate change and forecasting.
We’re trying to build an earth system model which will help model processes like how atmosphere and ocean interact in hydrological cycle, how vegetation and atmosphere interact, what happens at each step of hydrological cycle. This model is almost ready for climate forecasting. IPCC (Intergovernmental Panel on Climate Change) uses different models, but so far India was not participating with its own models. We have started this and now in the next IPCC (assessment report), we will participate with our own model. This will be a very major achievement. We started only in 2008 and, in just 10 years, we have built it.
Recently we also installed a very fast computer of eight petaFLOPS, the fastest in India, for weather and climate forecasts.
What kind of trends in climate impacts are you observing?
Several things are happening like sea level rise, extreme events are increasing, glaciers are melting much faster than they used to. These indications are always there. The only issue is these are very broad parameters. If somebody asks, for example, what will happen to a city like Hyderabad due to climate change, then there is a problem. If we have a large area, our predictions are pretty good. As you predict for a longer time, spatial scale also has to increase. I can give a very good forecast for Hyderabad for the next six years, but if you ask what will happen in Hyderabad in one year, then there is a problem.
What is it that we need to focus on to improve weather forecasting?
In weather forecasting, we are as good as anybody else. We are concentrating more on extreme events like lightning and thunderstorm or say a cloudburst because, if we see lightning alone, in Maharashtra it kills 400 people every season. The problem is that lightning in Maharashtra also occurs without rain, so it is a slightly different phenomenon there. We have now put our instruments to understand it better and maybe in the near future we will be able to predict it 3-4 hours ahead. We also have to identify clouds based on positive and negative charges for this purpose.
Is just disseminating weather forecast enough to ensure safety of people?
If you take the case of Tsunami warning system on the east coast there is awareness among the people living in states of Odisha, Tamil Nadu, Andhra Pradesh due to frequent hazards like cyclones and tsunami. But this awareness is not there on the west coast, like in Kerala in the cyclone this time despite timely warning, people didn’t leave the area because they are not used to seeing such hazards regularly. The government should educate people since this area is also vulnerable.
Three things are important — there should be a forecast, which is our job. The second is the government’s response in terms of necessary infrastructure to communicate and evacuate areas if needed. The third is consciousness of the community. If they don’t do anything, then there is nothing you can do. This we are seeing all along the west coast.
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