Global race to create better climate change simulations: Indian-origin scientist
The latest report of the Intergovernmental Panel on Climate Change (IPCC) report has implored nations to act to reduce carbon emissions. Meanwhile, this Indian-origin scientist is part of the team working behind the scenes to establish the scientific modelling upon which IPCC’s claims are based. Dr V Balaji of Princeton University is also a laureate of the ‘Make our Planet Great Again’ programme initiated by French President Emmanuel Macron as a response to the United States leaving the Paris agreement. In an exclusive interview with the Hindustan Times, he talks about climate science, modelling systems and his views on how the Anthropocene age is unfolding.
Q: Can you tell us what climate modelling is?
A: Let’s first think about any scientific study, say you’re probing the link between smoking and lung cancer. The way you establish that link is: you compare a population of smokers against a population of non-smokers, and you look at the relative rates of cancer incidence. The populations must be alike in every other respect: each group has women and men, rich and poor, urban and rural, etc. If the rates of lung cancer are different, and no other factor other than smoking can explain it, the link is established.
In the case of the planet, if you ask yourself what’s the effect of continually adding CO2 (carbon dioxide), you have a problem because there’s only one Earth. So, you build simulations, computer models of the Earth that resemble the real planet. Then you can do a similar experiment. The ‘smokers’ are the models where you subject them to heavy industrial pollution. The ‘non-smokers’ are the ones where you pretend that fossil fuel extraction never took place. Then you compare the temperatures and rainfall and so on. You will find that with CO2 the planet warms as observed since the Industrial Revolution, without CO2 it doesn’t.
That’s what a climate model is: it’s a computer simulation where we put in everything we know about the natural processes in the atmosphere and ocean and biosphere. For the long-term changes, we play various political ‘scenarios’, ones where there is planetary scale action to control emissions and ones where people refuse to wean themselves off fossil fuels even as the effects of climate change are felt all around us. Climate models will tell us likely outcomes across these two different futures.
Q: What is the Coupled Model Intercomparison Project (CMIP)?
A: The reason we believe these models is that we study them to see how well they resemble the real planet. Of course, being scientists, we don’t all agree and compete to build better simulations. The CMIP is a sort of Olympic Games of climate models, where every six years or so all the model builders engage in friendly competition to see whose model is best at different aspects of climate change, for instance around the Indian monsoon, or the disappearing Arctic ice. As a nice side benefit, the results also give you the best consensus across all the world’s experts on the state of the climate, what we are all collectively quite certain about, what we still need to study more, and these results are given to the world in the form of IPCC assessment reports. The sixth of these, CMIP6, is currently underway and we can expect to see the assessment IPCC-AR6 in 2021.
The models are very expensive to run. A typical model runs on a supercomputer and we are constantly making them better. Think of it as a camera with an ever-improving zoom lens, these models are like that. Each generation gets to zoom in and see more details. For instance, now we can ‘see’ tropical cyclones directly in our models, and see whether they become stronger with climate change and whether there will be more or fewer.
Q: Can you tell us about your work with regards to training in the use of climate models in developing nations?
A: If you look at early IPCC reports, almost all the results came from American and European models. Of course, the models are of the whole planet: it’s all connected and winds and ocean currents go around the world and pole to pole, and you cannot study ‘American climate’ or ‘European climate’ in isolation. But still, people are most interested in results near them, so it’s understandable if an American scientist were more interested in sea level rise in New York and drought in California.
What about the Indian monsoon, South African drought, other concerns of the developing world, who will study those? I left India a long time ago, but I have remained Indian ‘dil se’. I have close friends and colleagues in Indian institutions. A decade or more ago, I started bringing experts from around the world to India every few years to teach modelling, did workshops in Bengaluru, Hyderabad, and Pune.
Also, after Nelson Mandela became president, a friend of mine, a great scientist, who was exiled during apartheid, went back and invited me to run a similar workshop in Cape Town. And I am proud to note (though I claim no credit, it is entirely the work of local scientists) that for the first time in CMIP6, there will be a South African and Indian model participating.
Q: Would you like to talk about the recent IPCC report and the science behind its predictions?
A: The 1.5 (degrees) Celsius target is an outcome of the Paris meeting of 2015. The IPCC went in with a 2-degree target and a group there, led by many island nations made a passionate case for 1.5 degrees that carried the day. This recent special report on the 1.5C target followed when the IPCC returned to the scientists and economists and asked, what would it take to get to 1.5C? The problem is that carbon stays for a long time in the atmosphere once emitted, so it’s a cumulative problem, and we are still paying the price for decades-old emissions. Every year you delay de-carbonization makes it less likely you will meet any target of survivable climate change. That is really the stark message of the report. We may eventually get to zero carbon or even negative emissions, but every year you wait to take action, you will increase the human and ecological cost.
Q: Would you like to predict how the world is going to be, especially India, given the increase in extreme weather events in recent times.
A: I don’t wish to paint dystopian scenarios of climate change. Yes, we can and should imagine freak storms and prolonged droughts, 50 degrees Celsius summer temperatures, large-scale migrations away from coastlines and newly formed deserts. All of those things will happen in South Asia and elsewhere. But you can also think of it as Mother Earth pleading with her wayward children, that there are no tribal solutions to a global problem, that this way of life, relentless consumption, is not bringing anyone any happiness or peace. Perhaps, to be optimistic, this anger and stress that everyone seems to be feeling is the voice of our collective consciousness, and we should be listening.