Feature interview with Dipayan Choudhury, Ph.D.

Dipayan Choudhury completed his undergraduate studies in Civil Engineering at the National Institute of Technology, Rourkela, India, and moved to Australia for his PhD investigating decadal hydrologic prediction using climate models. In 2018, he joined the IBS Center for Climate Physics (ICCP), Korea as a Postdoctoral Research Fellow to research the mechanisms that drive glacial cycles, focussing on abrupt inceptions and terminations. He is interested in coupled climate-ice sheet models to better understand the climate – cryosphere system, as well as public outreach and science communication. “Sharing good science alongside doing good science should be an equally important societal role of scientists.” says Dipayan Choudhury, emphasizing the importance of science outreach to increase the public accessibility of climate science.  

Q. What inspired you to become a scientist? 

Well honestly, I didn’t always plan on being a scientist. Growing up, I liked the applied side of science more than the theoretical side of things. Since my schooling days, mathematics and physics have always been my favorite subjects. So after high school, I went on to graduate in Civil Engineering with a focus on water resource management. During that time, I had my first taste of research when I worked on estimating the effect of climate change on empirical runoff estimation as my final year research project, and I thoroughly enjoyed it. I was fascinated by the conjoint interplay between climate science and hydrology and proceeded on to do a PhD at the University of New South Wales, Sydney. It was here that I was exposed to the many spatial and temporal scales at which our climate system works and got very interested in the physics side of things. Also, given the direct relevance of climate science research to our day-to-day lives, especially in the current times of climate change, I decided to pursue my career as a climate scientist. My then supervisor, Alex Sen Gupta, was also a big inspiration for me to move into climate science as the way forward.

Q. What is your main research subject and what are you currently working on? 

I work on understanding the mechanisms that drive glacial cycles using numerical models. Planet Earth’s climate history over the past million years is characterized by alternating cold and warm periods with and without large ice sheets covering the northern hemispheric continents. Essentially, these cold and warm states represent multiple equilibrium climate states based on differences in the external forcings. And while changes in the Earth’s orbit are generally accepted as the drivers of these glacial cycles, we don’t fully understand the inherent mechanisms. To this end, I use a novel setup that includes a climate model coupled with an ice-sheet model to understand the mechanisms driving the growth and decay of ice sheets. Currently, I am working on realistically simulating these ice sheet evolutions over 250-150 thousand years ago, one of the most interesting periods in the Earth’s past million years. 

Q. What made you to come to ICCP, Korea? How’s your life in Busan?

After completing my PhD in Sydney, I wanted to work on a research project different to my PhD. That’s when I came across this opportunity from ICCP, which involved using a whole suite of models to understand climate changes over timescales from the very distant past to the recent future. This sounded like a very exciting research area to me and on Skyping with Axel about the center getting its own supercomputer, I definitely wanted to come and work here. I also have had Korean colleagues in Sydney, and judging by what they had to say about life here, Korea seemed like a great place to live in.

My life in Busan has been pretty amazing so far. The people in center, not only the scientists but also the students and the administrative staffs, are very friendly and it is a lovely atmosphere to work in. We have very open discussions and I think that really helps with the collective progress we make as a center. Busan is a beautiful city along with very efficient public transportation and health services, which makes living here a breeze. I love playing volleyball and pool and have managed to get around to doing both pretty regularly here as well. Besides, I absolutely love Korean food and the scenery is an absolute delight. And given the relatively low living costs and the sheer convenience of things, life here is pretty fantastic.

Q. What is the primary driving force or motivation for your research?

My primary motivation is to better understand how climate and ice sheets influence each other, and how this coupled climate – cryosphere system responds to changes in external forcings. This helps us better understand, quantify and possibly predict the effects of rising CO2 concentrations, such as sea level rise from melting ice sheets. In these times of impending climate change and global warming, it is more crucial than ever to understand the different feedbacks and sensitivities of planet Earth to changing external forcings such as CO2. Our paleo history has seen massive reorganizations of the climate system, and thus paleoclimate can serve as an excellent testbed to understand and test hypotheses, as well as judge the fidelity of climate models. Given the periodic prevalence of massive ice sheets over the last million years, solitary climate models struggle in realistically simulating our paleoclimate. Only recently have our computers been capable enough for us to couple climate models with ice sheet models, and I use one such coupled setup to simulate past ice sheet changes. 

Dipayan Choudhury leading the tree coring activity during 2019 ICCP Climate Day

Q. You have some experiences of scientific outreach events at ICCP. What is your most memorable event? What do you think of scientists’ role in society? 

I absolutely love doing outreach events and have been involved in a fair few here in Korea. If I had to pick one, I would say the recent Climate Day under the theme of ‘Be a Climate Scientist for One Day’ at ICCP in November 2019, was a memorable one. Around 60 high school students and teachers from four different schools visited the center to experience some of the various facets of climate research. I lead a ‘Learning about Past Climate’ activity alongside Axel, where we went outside on a pretty nice day to drill some tree cores. The students were pretty enthusiastic and positively surprised and excited to learn that, while tree cores contain information over a tree’s lifetime, drilling cores in the ice sheets or under the ocean bed can inform us on changes over millions of years. Later, we sat down discussing all sorts of topics ranging from climate change to nuclear energy to Mars’s paleoclimate, and different career pathways in climate science.

While doing good science resulting in peer-reviewed publications is crucial to advancing the forefront of science, I personally believe that it is absolutely critical for scientists to communicate their findings to the general public as frequently and as clearly as they can. Primarily because most of the scientific questions that we scientists, climate scientists especially, try to address, are relevant not to a handful but to all of humankind. And it is our responsibility to communicate such science. For instance, I personally have non-climate-scientist friends who did not know what to make of the whole climate change debate; because the media portray a 50/50 share of scientists believing or discarding the human imprint on current climate change. And while there is a 97% consensus within climate scientists attributing the current climate change to humans, we probably are not doing an excellent job of communicating this to our peers outside our own immediate scientific community. Sharing good science alongside doing good science should be an equally important societal role of scientists. So, simple outreach events like scientists sitting down to talk to a bunch of high school students can go a long way in making science more accessible to the wider society, and might even inspire some to choose climate science as a career.

Q. What do you think of interdisciplinary collaborative research in science, especially in a field of climate physics? 

Climate science inherently encompasses studies of physics, mathematics, chemistry, biology, remote sensing and geosciences; just to name a few. For instance, building and running climate models, which are used to test hypotheses and predict past and future climates, efficiently require a certain degree of expertise in computer systems; analyzing their results involve a sound understanding of the sciences and programming; whereas validating these climate models involve collecting observational data which could entail being on months long expeditions on an icebreaker to Antarctica. And thus, most climate science research results from extensive collaboration efforts. This importance of collaborative efforts for good science is evident from the lack of single-author publications in our field. 

In these times of the impending climate change crisis with extreme events becoming more frequent than ever and the changing climate adversely affecting industries like agriculture and fisheries, it is even more pertinent to have interdisciplinary collaboration leading to research that can directly impact the society. Water resource researchers needs to account for the changing rainfall patterns, ecologists for wildfires and coastal scientists for the rising sea levels. Such interdisciplinary collaborative research is not only relevant for advancing climate science, but also to take these research outcomes out for societal good.

Q. What is your future research plan? 

I absolutely love working with coupled climate-ice sheet models to better understand how the climate – cryosphere system responds to varying external forcings, and plan on continuing to work with them. While I currently focus on studying past ice sheet changes, next, I would like to better understand how reorganizations of such huge continental ice sheets affected the global ocean circulation. Also, building upon our understanding of the climate-cryosphere system, I plan on investigating future sea level rise from melting ice sheets under the effects of increasing greenhouse gas concentrations. Eventually, it would be great to be able to conduct an all-out past-to-future simulation using a similar setup.