Self-introduction
Hello, my name is Samar Khatiwala. I’m a Professor at SILS, which I joined last year. I was previously Professor of Earth Sciences at the University of Oxford in the UK.
Broadly, my research concerns the complex interplay between the cycling of carbon through the ocean and the climate system. Understanding these interactions is one of the grand challenges in science as it helps us better predict the impact of human activity on the environment. My research ranges from analyzing field data to developing computer models to simulate climate change.
I teach a variety of courses ay SILS, many centered on the broad theme of “Climate and Society”. In my eponymously titled First Year Seminar we discuss everything from the basic science of global warming to its socioeconomic and geopolitical consequences. My new Advanced Seminar, “Environment and Society”, also stresses the interdependency between humans and the environment, whether it is through natural phenomena such as El Niño or the impact of tropical disease on economic development. I also teach more disciplinary courses in oceanography, chemistry and computer modeling.
Recent Research Interests
Much of my current research is on developing novel computer algorithms for climate simulation. Every 6-7 years, researchers at major climate modeling centers around the world run their models to predict future climate change. These simulations are then synthesized into a report by the International Panel on Climate Change convened by the United Nations to advise governments. Performing these simulations is however hugely time and energy consuming. Even on some of the biggest supercomputers, the simulations can take up to a year. My latest research has led to a new algorithm and software that can reduce that to a few weeks. You can read more about it in an Oxford University press release and this piece on The Conversation.
I am also investigating how the ocean can modulate climate, both in the past and future. Through a variety of complex processes called “carbon pumps”, the ocean absorbs and stores a huge amount of carbon dioxide (CO2) – the main greenhouse gas responsible for global warming. In previous research I showed that about 1/3rd of the CO2 emitted from fossil fuel burning ends up in the ocean. In more recent work, which is currently under peer review, I have shown that this fraction is likely to decrease in future as the ocean becomes more acidic and its circulation slows down because of global warming, a “feedback” that could accelerate future climate change.
But the ocean can not only moderate global warming, it might even cause the planet to cool down! In fact, over the last million years or so, the planet has periodically gone through cold phases known as glacial periods, the cause of which has been debated for many decades. In a recent study I showed that this could be explained by a combination of iron-bearing dust blowing off South America onto the Antarctic Ocean and sea ice acting as a lid to trap CO2 in the ocean. (Like Popeye and his spinach, marine algae need iron to grow but its availability is limited. The extra dust acts as a “fertilizer” to promote growth and remove CO2 from the atmosphere.)
Of course, the ocean absorbs more than just CO2. Using a combination of field data and mathematical modeling, I recently estimated than more than 90% of the “extra” heat trapped by manmade greenhouse gas emissions has been absorbed by the ocean. And just as well or we’d be frying!
Profile
I did my undergraduate studies in Geology at St. Xavier’s College before pursuing a Master’s at the Indian Institute of Technology, both in Mumbai. I obtained my PhD from Columbia University in New York, followed by a postdoctoral fellowship at the Massachusetts Institute of Technology. I subsequently was on the research faculty at Columbia until 2013, before moving to take up a Professorship at the University of Oxford. I moved to Waseda in Fall 2024.
