Climate Change: How sensitive to a Hydrologist?

Hydrologist’s projection on Climate Change won’t remain to be crucial?

1. Focusing mostly on Land Phase of the Hydrological Cycle (the movement of water substance on and under the earth’s land surfaces, the physical and chemical interactions with earth materials accompanying that movement, and the biological processes that conduct or affect that movement), while, not giving due importance to the Global Hydrologic Cycle (the distribution and spatial and temporal variations of water substance in the terrestrial, oceanic, and atmospheric compartments of the global water system), which remains very critical for the understanding of Climate Change? Why do we have only a very few studies remaining focused on climate change by Hydrologists?

2. Although, hydrology remains built upon the basic sciences of mathematics, statistics, physics, chemistry and biology, why is it not viewed as an interdisciplinary geoscience that remains built upon its sister geosciences – towards addressing Climate Change issues “critically”?

3. Why does much of the motivation for answering hydrologic questions continue to come only from the practical need to manage water resources and water-related hazards?

4. What happened to the fundamental components of atmospheric science and ocean science, although geosciences aspect of hydrologic science does cover geology, soil science and glaciology?

5. Is it due to the fact that an understanding of the basic physics such as rainfall as it occurs instantaneously at a given point (i.e., over a small, relatively homogeneous region of the earth’s surface) is not getting always extrapolated easily to an understanding of the hydrology of a finite area such as a drainage basin, over a finite time – resulting from the fact that hydrologic quantities and the factors that control them vary greatly in both space and time, while, it remains difficult and expensive to obtain data to characterize such variability?

6. Why did the ability to understand and model hydrologic processes @ continental and global scales not become increasingly important resulting from the need to predict the effects of large-scale changes in climate (despite, the significant focus on large-scale changes in land use)?

7. With actual rates of water movement remaining non-linear functions of the controlling quantities – towards extrapolating from knowledge of processes at small space and time scales to larger scales, is it becoming extremely difficult to deduce an instantaneous water-movement rate averaged over a region or over a period of time or both – and almost remains to be ruled out, even, if we have measurements of spatial or temporal averages of the instantaneous values of the variables (say, from satellite-based and remotely-sensed information) that control the instantaneous water-movement rate (related with a linear function)?

Dr Suresh Kumar Govindarajan

Professor [HAG]

IIT Madras

16-May-2025