India has to learn to live with an increasingly unpredictable monsoon. An overview of the science behind its forecasts, the impact of climate change, and lessons from traditional wisdom
Sopan Joshi | September 9, 2014
It is an article of faith embedded in each and every planning document: India must reduce its dependence on the monsoon. Must!
Agriculture’s share in India’s GDP has fallen well below 20 percent. Yet our economy is dependent on four months of rainfall, which provide 80-90 percent of all the rainfall over the country. Four years ago, the then RBI governor, Duvvuri Subbarao, was asked to list the two things that would determine inflation. Oil prices and the monsoon, he said, clarifying that the efficacy of his monetary policy depended on the monsoon. (It led to several critical articles in the media, including one titled ‘India’s monsoon dependence is wrong’ in the Financial Times of London.)
“I am not the agriculture minister, the monsoon is,” declared Chaturanan Mishra, union minister in the mid-1990s. “Indeed, the impact of the monsoon on Indian economy is very pronounced,” wrote PK Das, former director of the national meteorological service in his book The Monsoons. “It prompted a former finance minister of the government of India to say that his budget was ‘largely a gamble on rain’.”
Should it appear that these stories belong to the past, go back to the headlines of the budget finance minister Arun Jaitley presented two months ago. “The government will launch a nationwide rural irrigation scheme to insulate farmers from excessive dependence on monsoon...,” said a media report. For agriculture may be only 17 percent of our GDP, but it supports 50-70 percent of our population, directly or indirectly – that is between 600 million and 849 million people. Dealing with a failed monsoon figured prominently in the president’s address to parliament on June 9.
A 2006 academic study by two economists examined how India’s GDP was linked to the monsoon. They found a bad rainy season pulls down India’s GDP 2-5 percent, although a good monsoon does not create a corresponding increase in GDP. It implied India lacks the systems to make the best of a good monsoon.
Far from the dour world of economists, when Albert Uderzo, co-creator of the highly successful comic series ‘Asterix’ (Rene Goscinny had died in 1977), decided to send his lovable heroes to India for the first time in 1987, it was to end the serious drought that threatened not just the people of an Indian kingdom but also bring its ruling family to ruin. That being a comic, bard Cacofonix’s horrible singing brings the rain to India and everybody goes home happy (except the evil vizier Hodunnit, who wishes to become “the Rajah instead of the Rajah”).
If drought is one end of the monsoon spectrum, the other is floods. Each year, floods displace thousands, especially in the Indo-Gangetic plains and the state of Assam. The loss of life, property, livestock, crops and farmland is the short-term cost of floods. In the medium to long term, floods damage the means of production, impoverishing them, closing the door to rebuilding a productive life.
Be it academic or popular literature, monsoon is discussed either as a magical, mystical experience, or as a terrible affliction of which India cannot free itself – India managed to overthrow the British colonial rule but is at the mercy of an unreliable weather system. As if India’s appointment with greatness is cancelled by the truancy of clouds. Search the internet on ‘monsoon dependence’, and you are likely to run into pages upon pages that use terms like ‘vagaries’ and ‘over-reliance’. Talk to your friends in the corporate world or the manufacturing sector, you are likely to learn that monsoon can impact the demand and sales of everything from automobiles and television sets to fast-moving commodity goods. The stock market, needless to say, keeps a close eye on the monsoon forecast.
Headache of meteorological proportions
Indian meteorologists are routinely blamed for not forecasting the monsoon accurately. Even the expectations of the India meteorological department (IMD) are negligible. The unreliable monsoon made worse by meteorological incompetence, if you will. The assumption being: why can’t we forecast monsoon in this, our postmodern age, when we have so many satellites in the sky and powerful computer to crunch data for models? Add to that the fact that the monsoon is one of the world’s more rigorously studied weather phenomena, and the question stares us hard in the face. The answer lies in a closer look at what we know about the monsoon – and truth be told, not everything is known. Because meteorology, the study of the atmosphere, is not the easiest of sciences.
Science, in a nutshell, is about using what is known to find out the unknown – in other words, establishing variables by using constants. In the case of the atmosphere, there simply are just too many variables. So much so that weather forecasting became a serious affair only after the arrival of computers that could crunch vast amounts of data. But then getting meteorological data is not all that easy either, for there is a lot of atmosphere out there and much of it is out of reach for gathering real-time data. Winds and water vapour circulate high and wide over long distances, and in three dimensions.
The business of meteorology becomes particularly difficult in the tropical and sub-tropical regions. This has to do with receiving more and direct sunlight – meteorologists call it insolation. So, unlike in temperate regions, both land and water heat up much more in the tropics and this heat is reflected up in the air – hot air rises vertically, and this creates turbulence (the weatherman calls it ‘convection’). This makes tropical weather notoriously difficult to forecast.
Monsoons: India and the world
Then there is the southwest monsoon that operates upon Asia. The monsoon is not unique to India; monsoonal weather exists all across the tropics, from Africa and the Americas to Australia. But there is no monsoon as strong as that which hits us. It has been called the largest seasonal abnormality of the global climate system, because it causes the equatorial region to become cooler than the regions to its north. The Indian Ocean is unlike the Atlantic and the Pacific, which are connected from the north pole to the south pole. It is bound by land on three sides and to its north lies the greatest land mass on earth: Asia.
Between south Asia and the Asian mainland lies the tallest wall in the world, the Himalaya, into which rams the world’s strongest monsoon. The mountains, in fact, are the reason for the world’s strongest monsoon. During the summer, the insolation over the Tibetan plateau and the Himalaya creates a low pressure (a Low, in weather lingo), which then attracts the high-pressure winds from the southern Indian Ocean. These winds bring with them the moisture that we call the monsoon. But exactly where this Low forms is disputed.
About 100 years ago, early meteorological enquiries showed that the heating over the Indian subcontinent was the reason for the Low. Later, this hypothesis was discarded. It is now believed that the summer insolation over Tibet creates the Low high up in the atmosphere – the average elevation of Tibet is 5,000 metres above mean sea level. This, it is assumed, draws in the monsoon. There is, however, another section of meteorologists who believe the insolation over the Himalaya is a bigger reason for the Low.
The exact mechanism of the monsoon is still not known. It is not just Indian meteorologists, either. Scientists from several countries have enquired into this question; they are yet to find answers that settle all the questions. It is not just the IMD which gets its monsoon forecasts wrong. International weather researchers don’t do much better. One problem is the state of weather modelling. “At present, the biggest stumbling block in predicting monsoon rainfall appears to be the deficiency of models. In particular, the models fail to capture the detailed spatial structure of monsoon rainfall,” wrote meteorologist Jagadish Shukla, distinguished university professor at George Mason University in the US, in an assessment in 2007 in the science journal Nature. He wrote it after a conference at the Indian Institute of Science in Bangalore, which assessed critical meteorological challenges.
Climate change, lest you forget
All the models in use give varying projections, for example, on the relationship between the monsoon and the El Nino Southern Oscillation, says Bhupendra Nath Goswami, director of the Indian Institute Tropical Meteorology (IITM) in Pune. “The models are all inaccurate.” (It harks back to a maxim among physicists: “All models are wrong; some models are useful.”)
Goswami and his colleagues have been trying to understand how changes in the global climate regime, like global warming, affect the monsoon. Establishing this relationship is difficult in unimaginable ways. What is much clearer, though, is changes in the monsoon’s pattern. For example, there is no change in the overall amount of precipitation – there are year-to-year variations and some decades have been wetter than others.
Next, the IITM scientists compared rainfall data from 1951-1970 with that of 1980-2000. They found an increase in instances of heavy rainfall (15 cm and above). This means the intensity of rainfall is increasing, and the number of heavy showers has increased. Moreover, the number of days of moderate rainfall – the sort that farmers desire – has declined over the two periods, cancelling out the increase of precipitation in heavy rains. This pattern was consistent across central India.
As any hydrologist or farmer will tell you, heavy rainfall causes runoff; it does not give time for water to seep into aquifers and recharge groundwater. So we are looking at a decline in the kind of rainfall that is desirable and an increase in the kind of rainfall nobody wants. This means India is looking at greater instances of floods during the monsoon, and drought during the summer. Because moderate rainfall recharges groundwater, it makes the results of the monsoon available in the hot, sub-tropical summer.
Flood to drought, suddenly
Given that the monsoon is acquiring extremist tendencies, accurate forecast becomes of greater importance. People need to be warned whether they are facing a drought or a flood. However, just as the monsoon is becoming ill-tempered, it is also proving increasingly unpredictable. Goswami’s colleagues have found the errors in forecasting are actually increasing, doubling over the past three decades.
Just when you thought the complexities of tropical meteorology and forecasting the southwest monsoon had peaked, it has gone and become even more complicated. Extreme rainfall has a direct bearing upon the low-pressure systems, depressions and cyclones that drive the monsoon inland. When weather models make an error in simulating a case of extreme rainfall, it has a dominoes effect – it hits the model’s ability to predict Lows and depressions and cyclones.
M Rajeevan has been studying the impact of climate change on the monsoon at the National Atmospheric Research Laboratory in Tirupati. He has found a decrease in the frequency of monsoon depressions. This, he suspects, could explain the decreasing rainfall over Jharkhand, Chhattisgarh and other parts of east-central India; in this region, the monsoon’s onset has got delayed by five days on average. While Kerala gets less rain now than earlier, Maharashtra has to deal with more rainfall.
The chaos is spreading not just across space but also across time. July used to be the wettest month in India, and farmers used to prepare the fields for sowing of seeds in this month. Now, however, August is the wettest month. Already this year, there have been reports of delayed sowing in parts of Andhra Pradesh, Telangana and Karnataka. Monsoon irrigates the most important crop of the Indian subcontinent, the kharif crop. Such variations in the monsoon are bound to have an impact on food production. So where do we turn to find coping mechanisms?
How to tackle unpredictability?
It is worth asking this question of people who have been studying the regions facing the greatest wrath of the monsoon. Let’s take two extremes: northern Bihar, where floods are an annual affair, and western Rajasthan, a region the monsoon overlooks as a matter of habit, making it the home of drought. (The name Marwar implies a region of death.)
Nobody has invested as much time and energy in understanding floods in northern Bihar as has IIT engineer Dinesh Kumar Mishra. He has pointed out – year after year – that floods are becoming more and more unmanageable due to engineering interventions. The increase in flood-prone area in Bihar is a direct consequence of short-sighted moves like the construction of embankments along the river Kosi.
This is continuing since the 1960s; even recently, a new bridge built over the Kosi in Supaul district violated the recommendations of government committees, leading to tens of villages getting inundated. Because the bridge did not account for the volumes of water and silt the Kosi brings, it obstructed the flow of floodwaters. That sent a pulse of flood to villages that were within the embankments. These villages got trapped between the Kosi and its embankments.
For decades, Mishra has documented how people of Bihar have lived alongside the floods – they actually thrived on the floods, which brought with them the fertile silt of the Himalaya. This required taking into account the flow of floodwaters in land-use decisions. They did not look upon the floods as a curse; rather, they were a blessing. The government was not willing to let such lands be inundated. In its hurry to create large engineering solutions to prevent floods, it ended up stopping the floodwaters from receding into the river after the monsoon. So, land that was earlier water-logged during the rains now remains water-logged through the year, providing breeding ground to vector-borne diseases and damaging fertile land.
In western Rajasthan, people have looked at each drop of rainfall as a blessing. The city of Jaisalmer, for example, had a series of nine tanks linked to each other. Most years, there was hardly enough rain to fill up one. But in a good year, several tanks got filled up and the water seeped into the ground. This could be drawn during lean months of summer. One good monsoon, if harvested carefully, could provide drinking water for three to five years.
In a land that gets such little rainfall, there are no less than 40 names for clouds, points out Anupam Mishra of the Gandhi Peace Foundation’s environment cell, author of two popular books on traditional water management systems. People of Rajasthan have based their engineering on the presumption that the monsoon is variable, Mishra has reminded repeatedly. They planned for the worst and hoped for the best. No region in India has such a rich range of water management systems as Rajasthan. This is perhaps the reason the Thar is often described as the world’s most densely populated desert.
Given what the meteorologists are telling us – both about what they know and what they do not know – preparing for what lies ahead requires that India pick up useful tips from time-tested systems that have helped people survive and prosper. Our scientists are telling us that we face greater floods and drought. Perhaps it is time to think of harvesting floods and drought-proofing our land. To deal with extremes of a changing monsoon, we need to learn from people who have made opportunities out of those extremities. As also the value system that made it possible for people to find ways of living with the monsoon over thousands of years (the southwest monsoon is anything between 10 million years to 55 million years old). That value system is still around, and it is coded in mythology.
Hydrology defines a subcontinent
Before the term ‘monsoon’ gained currency through modern meteorology, the rainy season was known only by its old name: chaturmas. In Sanskrit, it means four months. Although the residents of this subcontinent did not have access to meteorological observations and definition, they were far more aware of the importance of chaturmas (called chaumasa in everyday lingo).
In fact, the term for year in several Indian languages is ‘varsh’, which is linked to the term for rain, ‘varsha’. In several calendars popular in India, the year is built around the monsoon. A good way to access the structure behind these calendars is to consider the mythological stories that come along with them.
One of the most prominent and dramatic stories explains why Vishnu, the CEO of the Hindu pantheon of gods, goes to sleep during the monsoon. As it often happens with mythology, the story has several versions depending on region, language and caste. All versions agree on characterising Bali as a powerful and just Asur king. His rule was defined by prosperity and security; after securing the earth, Bali had established his control over the heavens, after displacing the reigning Indra, Purandhar, god of the Devta.
Upon losing power, Purandhar seeks help from his patron Vishnu, who relents (according to a version from the Bhagwadpuran). He disguises himself as a Brahmin boy, approaches Bali during a sacred ritual, and asks for three steps worth of land. Bali has been warned by his advisers that this is no ordinary boy but Lord Vishnu himself. But he shows a remarkable devotional streak and says something to the effect that the Lord giveth and the Lord taketh away. He grants the Brahmin boy his wish. This is when Vishnu begins to expand his size to unimaginable proportions. In one step, he covers all earth; his next step covers the heavens. He turns to ask Bali where he can put his last step. Bali offers him his head. Vishnu steps on him, sending him deep into the underworld. But Vishnu is so pleased with Bali’s devotion that he grants him a boon: after Purandhar’s reign ends, Bali will become Indra. Vishnu also commits to sleep for four months – chaturmas – at Bali’s doorstep in the underworld. With Vishnu sleeping, all the 33 million Hindu gods go to sleep for four months.
Millions across India observe the date of the gods going to sleep even today. It is the eleventh day of the second fortnight in the lunar month of Ashadh (in 2014, it fell on July 8). This is the Dev Shayani Ekadashi, also called Dev Soni Gyaras. Through the chaturmas, the believers do not bother about the gods; the gods are aware of this, so they go into hibernation. For this is the time of monsoon crop kharif, the time for water management. There are hardly any social celebrations. There are no weddings in several communities across India during the monsoon; even among those who do not believe in Vishnu. People may or may not share their gods and religious belief, but they do share the monsoon. In Buddhist literature, this period is called Varsha Vaas, or the habitat of rain. Among Jains, the monsoon is a time for penance, of staying in one place and shunning travel, of self-discipline.
With the harvest of the crop, chaturmas comes to an end. Diwali is the harvest festival that ushers in a period of consumption and plenty. Eleven days after Diwali, Vishnu and the other gods wake up on the Dev Utthan Ekadashi, also called Dev Uthani Gyaras. The wedding season begins right after.
This calendar has regulated monsoonal behaviour for hundreds of years. It provides a time for self-discipline and a time for indulgence – all built around the monsoon. If you put in the hard work during the monsoon, you were bound to reap rewards later. Land-use decisions, too, were taken during the chaturmas in view of the rainfall. For drainage of water was primary to avoiding flood and harvesting rainwater. This was the code for survival. For the god of rain is Purandhar, the current Indra. Purandhar means city-destroyer. People knew that settlement that does not keep in mind the rain that Purandhar sends down will get washed out.
We will do very well to remember this lesson. Our cities have little use for their water bodies because they are supplied water from distant rivers and lakes through pipelines. So cities have paved over all their land, leaving no space for the egress of runoff from the monsoon rains. Mumbai learned this lesson the hard way on July 26, 2005, when Purandhar sent down almost a metre of rainfall in one day – one of the greatest downpours on record. Death and destruction was rife across the city. The city was reminded that it had paved over its small river Mithi, and there was no way for the water to get out.
With the monsoon producing heavier rains than earlier and getting more unpredictable, our cities are tested each rainy season. They experience widespread water-logging. Delhi’s spanking new airport terminal T-3 had knee-high water in the 2013 monsoon. Our cities and the powers that run them will have to relearn the power of the rain god. They will have to remember that there are greater powers. Like the monsoon.
This story first appeared in Magazine Vol 05 Issue 15(01-15 Sept 2014)
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