I have recently been reading ‘An Idealist Way of Life’, written by S. Radhakrishnan, the philosopher-educationist-statesman, back in 1932. In the last chapter of this book, titled ‘Ultimate Reality’, Radhakrishnan begins by stating that there are certain pervasive characteristics of the world, the first of which is that it is an ordered whole. Nature has unbroken continuity and complete unity within which is a system of intimate relationships. But Radhakrishnan is quick to add that the order of the universe is not a mechanical one. What we call scientific laws only represent working hypotheses. They do not constrain or dictate to nature.

Nature is not a mechanical tyranny, says Radhakrishnan. And to prove his point, in the typical style of many of his brilliant arguments, he draws inspiration and support from the Bible: “If mechanism were true, the writer of Ecclesiastes, who laments that ‘the thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun’, would be faithful to facts, but the truth is nearer what the Book of Revelation declares, ‘Behold, I make all things new.’ ” Radhakrishnan goes on to say that ‘time introduces something new in the properties of things’ and that ‘the historical process has in it two elements of continuity and novelty’.

Radhakrishnan’s description of nature in the two simple terms of continuity and novelty has tremendous relevance to the science of the atmosphere and the professional practices of meteorology. It explains in one go that weather forecasts are scientifically possible and at the same time makes them liable to error. The continuity aspect of nature will allow us to make good predictions of weather and climate as long as nature is in a mood to just carry on with itself. But we are sure to go wrong, when nature decides to choose the novelty option instead.

Nature is full of cycles. First of all there is the energy cycle, which redistributes the sun’s energy within the earth-atmosphere-ocean system and maintains its equilibrium. Then there is the hydrological cycle, which brings vapour from ocean to land and makes it rain, and then makes the rivers flow back into the ocean. There is the carbon cycle, and so on. We also have the atmospheric circulation cells and the oceanic conveyor belts within which air and water goes round and round. As long as there is continuity, there is predictability.

But the atmosphere is full of novelty. Perhaps nature does not want human beings to live a monotonous existence. The southwest monsoon indeed comes every year without fail, but no two monsoons are alike. The onset over Kerala, the total rainfall over India, the spatial distribution, the duration of dry and wet spells, the number of monsoon depressions, the date of withdrawal, are all new with every monsoon. This is why the monsoon remains as unpredictable as ever even while we continue to learn more and more about it. As if every year, the monsoon hits upon a new design and fashions itself accordingly.

Likewise no two winters are the same. Sometimes the cold sets in early, sometimes December is the coolest month, sometimes winter lingers on beyond March. It is the same with summers too. Every tropical cyclone behaves a little differently from its predecessors, takes a slightly altered path.

Do all the elements of the atmosphere work in conformity with an orderly plan, or do they have some freedom to act? Do they have a mind of their own? “Does a cloud chart its own course? Does it decide which rooftop to pour upon?”, Jagjit Singh had asked in one of his famous ghazals. (“Kis raha pe chalana hain, kis chhat ko bhigona hain…?)

The atmosphere is neither a totally ordered system nor is it a totally chaotic system. The orderly part will remain predictable and we may even improve our skill in the years to come with better science and technology. But the chaotic part is sure to give us that newness of life from time to time. Nature’s message is that we should not be surprised by surprises and we should be prepared to expect the unexpected!