Interview of Prof. V. Ramaswamy

Prof V. Ramaswamy, Director of NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL), and a Lecturer with the rank of Professor in the Atmospheric and Oceanic Sciences Program and the Princeton Environmental Institute at Princeton University, US was in IIT on Wednesday to deliver the Institute Lecture “Scientific Understanding and Prediction of the Climate System: Recent Developments to Obtain Continental-to-Regional Trends and Extremes". In an interview with Vanita Srivastava he talks about the importance of climate study, the challenges and more.

How important is climate study in the current times?

Several sectors of society are dependent on environment of which climate is an important factor. There is short range information but we need to have information for a longer period especially for planners who work on a 10 year time scale. Then there are those who need to have climate information on a time scale of 40-50 years like those engaged in construction of highways and dams.  In the past, till late 50s, people generally looked at the mean values for example to analyse the incursion of water into the land or heat waves or rainfall in a particular region for societal planning purposes.  Now in the last few decades, as the temperature started rising significantly,  there is a growing importance on non-stationarity viz., mean climate itself undergoes changes. Climate is variable, and changing. As the need has arisen to obtain weather and climate information on spatial scales that matter to society, research has scaled up to keep pace with the demands fromsociety. In addition, there is the concomitant demand for credible information over time scales ranging from tomorrow’s weather to sub-seasonal to seasonal to inter-annual to decadal to the centennial.

What are the main challenges encountered in climate study?

There are two aspects to the challenges .On the scientific aspect, the challenge is resourcing the infrastructure for sustained observations and especially the observation of important climate variables. If you want to know the variability and change, you have to do continuous monitoring which tends to be expensive. Modelling is another major challenge. To predict the future and capture the complexity of the climate system, you need computer models which in turn require high-performance super computers. Another major challenge relates to communication. You cannot just tell for example a farmer – here, this is the information from climate science - and leave him/her to do the interpretation of the complex science for his/her use. There has to be value added information which tells the person what the scientific information is conveying relevant for their usage. For example, they may want to know more about daily maximum rather than the daily mean temperature. Climate science is looked as complex but there can be lots more done to communicate and interpret that complexity for the customer and stakeholder. In addition, there has to be credibility of the science and the information conveyed.

What is your area of work?

Our lab in NOAA is building and developing new models as part of world -wide research, based on advancing fundamental knowledge, and calibrating them and, depending on the flaws discerned, we bring about improvements. My research has mainly focussed on human influence on climate through modelling and use of observations including the effect of aerosols, greenhouse gases, land use change, aviation , and effects of natural changes like change in the sun, volcanic activity. We are trying to understand the factors that govern climate variability, change, and prediction. There are two aspects involved in scientific understanding leading to predictions –the initial value problem in which mathematical equations are solved to figure out what will happen tomorrow. Then there is the boundary value problem due to forcings (e.g., increases in greenhouse gases, aerosols)acting on the system. For a 10 years prediction, the problem to solve is a combination of initial values and boundary values. People want information on temperature beyond the next 24 hours. Oceans play an important role in climate study. Oceans have a large thermal inertia because of water and this constitutes memory in the system that can have an important role in the seasonal and longer-range forecasts. Our long term objective is to devise state-of-the-art models which can make predictions well in advance and, importantly, deliver accurate and precise information with confidence levels, such that this is more useful to the stakeholder and customer than at present.

How do you see the domain of climate study in India?

Climate study has advanced significantly in India over the past couple of decades. When I was thinking on doing a doctorate in atmospheric science in India, there were actually just two universities that had full-fledged departments in the atmospheric sciences. Climate is not a pure basic science like physics and chemistry. It is an interdisciplinary field that has its roots in all of the basic sciences. The scope and ambit of this subject has over the years grown substantially. Besides the major academic institutions , other universities in India have started this study in some or the other form, attracting students and post-doctoral scholars. Vulnerability of society to variations and changes has accentuated the awareness of climate. There is a stronger need for infusion of knowledge and sharing wherein scientists and decision-makers can feed appropriate, credible information for the betterment of society.