Professor Krishna AchutaRao: A Scholar, Institution Builder and Gentleman

Professor Krishna AchutaRao (April 5, 1964 – September 4, 2026) was one of India’s leading climate scientists and a respected member of the global climate science community. His influence was broader through the many roles he played in academic life, and across them all, he brought the same intellectual generosity, rigour, curiosity and genuine desire to see others succeed.

For more than three decades, Krishna contributed to some of the most important questions in climate science: how the climate is changing, whether that change can be attributed to human activity, the role of climate change in extreme weather, and what these changes mean for adaptation by societies. He was deeply involved in the international climate science enterprise, including the Intergovernmental Panel on Climate Change (IPCC) and the World Climate Research Programme (WCRP). Much of his later work was increasingly focused on using climate science to improve climate action in the Indian context.

For those who knew him at IIT Delhi, however, Krishna was more than a distinguished scientist. He was a much-admired teacher, a valued mentor, a committed institution builder, and thoughtful colleague. He combined scientific ambition with intellectual humility, a formidable command of his field with an ability to listen, and a commitment to building institutions with a genuine concern for the people within them.

There was also something distinctive about his approach to academic life. In his science, he was very much at the forefront, willing to adopt new tools and approaches to address important questions. Yet his approach to academia reflected qualities that seem increasingly old-fashioned: a commitment to quality over quantity and a quiet humility about his own achievements.

A scholar

Krishna’s academic journey began at BITS Pilani where he received a Bachelor’s degree in mechanical engineering and a Master’s in mathematics in 1986. He subsequently moved to the United States for his doctoral studies at Tulane University, where he received his PhD in 1994 for research on natural climate variability, climate sensitivity and poleward heat transport.

He then spent nearly two decades as a researcher at Lawrence Livermore National Laboratory in the United States before returning to India in 2007 to join the Centre for Atmospheric Sciences (CAS) at IIT Delhi.

A major part of his scientific career was devoted to detection and attribution, one of the fundamental questions in climate science: could changes in the climate be detected, and could they be attributed to human activities? As one can imagine, this was one of the key issues in the climate arena, whose resolution by climate scientists put to rest any doubts over the existence of climate change and the significant role of human activities in driving, which became the rationale for the Paris Agreement ultimately, and, in turn, the climate mitigation actions being undertaken around the world.

As the science evolved, so did Krishna’s questions. After returning to India, he increasingly turned his attention towards regional climate change, extreme weather events, climate risks and adaptation. 

One important area was extreme event attribution: understanding the extent to which human-induced climate change influences the likelihood and severity of individual events. This work helped connect the abstract problem of global climate change to impacts experienced by local populations. The stakes are considerable. The annual costs of extreme weather events have been rising, with the estimated economic losses from just the 10 largest disasters last year reaching around US$120 billion globally, alongside thousands of deaths. Such attribution work is also increasingly relevant to efforts around “loss and damage”, as establishing the contribution of climate change to extreme events can help inform discussions about responsibility, compensation and support for affected communities.

Krishna worked extensively on future extreme events, such as heatwaves, and on how their changing characteristics across different regions of India could inform adaptation planning and policy.

His interests extended to other environmental challenges as well. He became increasingly engaged with studies around air pollution, including questions around measurement, analysis and the scientific basis for effective pollution control. This reflected a broader feature of his scientific thinking: he was interested in the physical processes underlying environmental problems, but equally in how scientific knowledge could be used to address them.

Krishna’s contributions were recognised internationally. He was associated with the Intergovernmental Panel on Climate Change (IPCC) from 2001 and served as a lead author for both its fifth and sixth assessment reports. He also served in the steering committee of the World Climate Research Programme (WCRP).

As a scientist, Krishna was dedicated to meticulous science, and this was paired with a principled concern for the human implications of the processes he studied. He was deeply concerned about the consequences of climate change, particularly for those who had contributed least to the problem and for future generations. He once described climate change as an “intergenerational Ponzi scheme”, expressing his frustration at the burden being passed on to people who had little role in creating it.

Despite this international standing, Krishna was remarkably unassuming about his own stature. His attention was usually directed towards the quality of the question, the evidence, and the people around him.

An institution builder

Krishna understood that scientific progress depends not only on individual researchers but also on the institutions that motivate and enable them to be productive in their work.

At CAS, he played an important role in broadening its scientific vision, especially when he was the head. CAS has a long history of excellence in atmospheric science, particularly in advanced analytical and modelling approaches to understanding atmospheric processes. Krishna, together with his colleagues, helped bring climate science more explicitly into this vision, contributing to the growth of a broader climate research community at the Centre.

He also envisioned a state-of-the-art atmospheric observatory for IIT Delhi. The observatory, being developed at the Institute’s campus in Sonipat, is intended to generate long-term observations of both air pollution and climate. It represents an important expansion of the Institute’s capabilities beyond modelling towards sustained observations that can address policy-relevant questions while also enabling process-level scientific research and discovery.

Krishna was similarly instrumental in the development of the Centre of Excellence on Climate Change Adaptation (COE-CCA) at IIT Delhi. Established under the aegis of the Ministry of Environment, Forest and Climate Change, COE-CCA's hub-and-spoke network model is also intended to be broad-based, locally relevant, and enhance interactions and capacity in knowledge entities across the country.

His institution-building extended beyond the climate domain. As Dean of Faculty at IIT Delhi, Krishna worked to strengthen and streamline several aspects of the Institute’s academic functioning, including faculty recruitment and onboarding and faculty development. He approached these responsibilities with the same care and intellectual seriousness that characterised his scientific work.

A teacher and mentor

For many across IIT Delhi and beyond, however, Krishna’s most enduring contribution will be measured not in papers, reports or institutions, but in the people he influenced.

He was a committed mentor who genuinely wanted students and younger colleagues to grow. He encouraged independence and supported people as they developed their own scientific identities.

As a teacher, he was demanding in the best sense. He did not believe in spoon-feeding. Instead, he pushed students to think critically about the foundations of their work. He would return to fundamental questions: Is this the right question? Is it worth asking? And are the methods being used appropriate to answer it?

This emphasis on scientific reasoning, rather than simply acquiring knowledge, was central to his approach to teaching. He wanted students to become independent scientists – to question assumptions, evaluate evidence, and defend their conclusions.

A gentleman

Perhaps the most striking thing about Krishna was the way his intellectual stature coexisted with his humility.

He had an extraordinary command of climate science, but he never used his knowledge to make others feel small. He was generous with his time and remarkably supportive of students, faculty and staff. He could be rigorous in his criticism while remaining respectful of the person whose work he was challenging.

He was also a wonderful listener. Conversations with Krishna could range from a difficult scientific problem to food, music, or Test cricket. One often came away having learnt something or simply feeling a little lighter.

There is an old saying that a tree laden with fruit bends low. Krishna embodied something of that idea. His achievements were considerable, but they never seemed to make him less approachable.

Perhaps this is what made him unusual. Many academics are accomplished scientists. Many are good teachers or mentors. Some are effective institution builders. It is rare to find all of these qualities in one person.

Krishna brought cutting-edge science to questions that mattered, but he also held on to an older idea of what it meant to be an academic: that scholarship should be rigorous, that institutions should be built for the long term, that students should be encouraged to think independently, and that knowledge carries a responsibility towards others.

In that sense, he was both ahead of his time and, in the best possible way, rooted in values that should never go out of fashion.

His passing is a loss to climate science, to IIT Delhi, to the students and colleagues he supported, and to the many institutions and communities that benefited from his work. While he will be deeply missed, his legacy will endure in the science he helped advance, the institutions he helped build, the students and colleagues he mentored, and the standards of scholarship and humanity he quietly set for those around him.

Shahzad Gani is Assistant Professor at the Centre for Atmospheric Sciences, IIT Delhi, and knew Krishna first as a student and later as a colleague. Ambuj Sagar is Professor at the School of Public Policy, IIT Delhi, and worked closely with Krishna on various academic and institutional matters.

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