Interview with Jagadish Shukla, author of A Billion Butterflies: A Life in Climate and Chaos Theory

The Hindu

24-06-2025

Eminent climate scientist Dr. Jagadish Shukla has devoted a lifetime to improving seasonal weather predictions, and especially monsoonal predictions for India. He grew up in rural Uttar Pradesh and seeing how people's lives depended on the monsoon and information around it, made it his mission to forecast seasonal weather events. In doing so, he has changed the course of modern weather prediction. He tells the story in his new book, A Billion Butterflies: A Life in Climate and Chaos Theory, a personal memoir as well as a log about the course weather and climate science has taken. Edited excerpts from an interview.
One of the things that makes your book fascinating is that it deals with a topic that people talk of daily, but has a limited understanding of. A fascinating line says, 'Climate is what you expect, weather is what you get.' What does that mean?
All that it means is that long-term average weather is climate. Typically, a 30-year average of values is considered as climate. So what you expect to happen on a certain date is based on this, and what actually happens – weather -- is over and above that. The reason it is important to understand this is that we tend to think climate is fixed, but it is not. It is changing every day and changing in a well defined manner and it is also different over different places.
The title of the book and your area of study refer to the chaos theory and thereby the butterfly effect. When applied to climate science, does it really mean that we are looking at the variables that go into the forecast models?
First of all, the equations that define weather and climate are the same; just that weather does not consider some big factors like chemistry, aerosols etc. The butterfly effect is all about weather. Predictions are based on what happens today and the equations chosen. However, these predictions, hold good only for a few days.
Even with improvements in computing and satellite observations, accuracy begins to get tricky after 10 days. This is because the equations which do the prediction are non-linear and small errors on the first day can lead to very large variations a few days ahead. And that's the origin of the word 'butterfly effect' as defined by one of my advisers, Professor Edward Lorenz from MIT. What is even more interesting is when he first spoke of this effect on forecasts, he used the analogy of a seagull flapping its wings over an ocean. The butterfly terminology came much later because the actual graphical result of his paper resembles a flapping butterfly!
My motivation when studying the monsoon was to find exceptions to the butterfly effect and I found it eventually -- it was the ocean temperatures. Science is not just about experiments and ideas; it is also about communicating those ideas. My work showed that once ocean temperatures are included as a factor, even a billion butterflies flapping their wings could not affect it significantly.
It is evident from your work that meteorology and forecasting has improved dramatically, including in India. How are we placed in terms of how we look at climate change?
Tthe very first supercomputer that came to India in 1989 was for weather. While we have kept pace since and our weather forecasts are comparable to what is happening globally, our monsoon forecasts still need work.
In terms of climate, it is disappointing that developed countries like the U.S. has shown great reluctance to accept the reality of climate change. India requires a national effort towards climate assessment and adaption for buy-in and action from policy makers and effective governance.
You were the lead author of the IPCC assessment report that shared the Nobel Peace Prize along with Al Gore in 2007. Do you think it was a kind of a global turning point in terms of climate change discourse?
I think so. And it had one good effect as well as a very bad one.
The good part was that this was the first time scientists could conclusively state and prove that human activities are negatively affecting global climate. Eight years later at the Paris climate change conference (COP21), nearly 200 countries agreed to a legally binding international treaty to make efforts to limit global warming and temperature rise.
The bad news came from the U.S. and perhaps elsewhere. This was the point where the fossil fuel industry stepped up their attacks on actively trying to disprove climate science through both overt and covert means. It really is the worst combination of politics and profit motives undermining one of society's greatest challenges.
It almost seems as if your life is driven forward by destiny. And you keep referring to the monsoon. How much of a critical part was it in your early life and in shaping your career?
As far as my personal life was concerned, especially early on, it just felt like things were happening on their own; with many things being beyond my control. It was much later that I started making my own decisions.
So far as the monsoon is concerned, that certainly has been the central part of my journey. In my village Mirdha, monsoons or its failure, had a profound effect on life, including food on your plate. And so, I went to MIT with a very clear aim – to be able to predict the monsoon. Because that was the way I felt I could help my village, my country, the agricultural community. Twice in my life I was very close to shifting to other spheres of work, but my interest and efforts remained focused on the monsoon.
What does a life dedicated to scientific rigour mean? Does it take a toll on your personal life?
Oh certainly, it does. When you are excited about what you are doing and you think you are making progress, you tend to ignore some aspects of your personal life. I often feel that perhaps my children did not have enough time to be with me and know me better. There was a point where my daughter asked what her dad looks like. That said I am indebted to the complete support and trust of my wife.
You have gone back to your village and helped set up a woman's college and contributed otherwise nationally as well. So would you say that your life has sort of come full circle?
I wouldn't call it a full circle; rather life has been like that all along. I was always involved with family, Mirdha, India and science – to the extent that some people believed that I was doing all of this to eventually run for a political office!
We have seen that climate change affects certain strata of society more than others. How well do you think we are prepared to adapt to these changes?
People say that climate change is the biggest problem facing us. For me, it is only one of the two biggest problems. The other being inequality and lack of social justice. In India for example, we go to international forums and say that our per capita income is relatively small and so we should be exempt from taking serious climate action. But when you look closely, it is less than 10% of the population that is responsible for most of the actual emissions. While it is the remaining 90% that will bear the brunt of the impacts of climate change.
As far as I am concerned, climate action in the end is a sort of a fight against the injustices that exists in this world.
What really stands out from the book is how you are driven by a great belief in your own understanding of life. Even if this has meant standing contrary to existing view points.
Yes, I have conviction. But I have also been open to being proven wrong.
In modern society, especially democracies like the U.S., there is always a lot of talk about liberty and freedom; but not so much about happiness. Thanks to my mother, right from my childhood, I have understood that giving to others and society is one of the best ways to attain this.
Billion Butterflies: A Life in Climate & Chaos Theory Jagadish Shukla Macmillan ₹699
The interviewer is a birder and writer based in Chennai.