Monsoon – a Lifeline for 1.5 Billion

Towards the end of May each year, hundreds of millions on the Indian subcontinent look anxiously to the skies. By now the hot spell has been building up over many weeks. Soil, plants, animals and humans alike long for rain. It is not only a relief from the scorching heat, but it is also the source of life for farmers between Himachal Pradesh and the southern tip of the subcontinent. Nowhere else on the planet do so many people depend on a rainy „season“ such as India’s Southwest monsoon. And the coming of the monsoon is an issue in newspapers and media. Its timely onset determines the yields of rice and vegetables – and the economy as a whole. In spite of being promoted as „Make in India“ industrial and software hub, India’s economy still depends on agriculture.

Monsoon rains in South Asia were the stuff of travel tales, of songs (rain raga) and lyrics. It comes with wind and thunderstorms and splashes down on the hardened soils and the starving trees. And it comes so much „just in time“ that you can fix your calendar to it: 1st June was always the day when the clouds rose in the sky above, lightning started and the wind roared through the eucalyptus trees around our house in the Palni Hills where we lived in the early 1980ies. And then rain would start and go on for days.

Monsoon shower at a bus stand in Tamil Nadu, July 2007

In the pattern of global atmospheric circulation, the monsoon, more precisely: the monsoons are a distinctive feature. Originating from the Arab word mausim (season) they are defined as wind patterns that change direction by at least 120 degrees In South Asia they change direction by 180 degrees. The Southwest monsoon between end of May and early August brings humidity and rain from the Arabian Sea to the coast and interior in the west of the subcontinent. The Northeast monsoon does it for the east coast between October and early December.

The map to the left shows the annual total. The summer monsoon contributes by a large share to the annual rainfall in Indian and its neighbours. But the Northeast monsoon is vital to the southern state of Tamil Nadu and also for the northeast of Sri Lanka (the „dry zone“). Another way to illustrate the seasonal gains and deficits is shown in the two climate graphs. Kochi on the west (Malabar) coast has its major rainfall in June and July, Pondicherry, on the east (Coromandel) coast receives most rain in October and November. But do not overlook the totals: over the run of a year, Kochi receives three times more rainfall than Pondicherry.

So precipitation is spread unequally across the subcontinent’s triangle. While the west coast, aided by the the barrier of the Western Ghats, is drowned, those east of the ghats just can watch the rain clouds. In the two states, Kerala and Tamil Nadu, this has created two different natural as well as cultural landscapes, if not mentalities: Kerala can afford to let the waters flow. It harvests the monsoon rains for its hydro-electric power generation. Rains and rivers provide irrigation for paddy harvesting and the rich sediments in rivers, lagoons and off-shore create a rich variety of fish. All along the coast coconut trees cover the endless villages and towns. The Malabar Coast is one of the most densely populated regions on this planet. No wonder that Malayalees are bit more relaxed. Apart from that the spices, but also tea and rubber on the slopes of the ghats make (and made) that coastal strip a preferred destination for traders and seafarers. Kerala is more open to the world than most other parts of India.

In contrast Tamil Nadu. The land of the Tamils depends on sophisticated canal irrigation taken from rivers like Vaigai and Kaveri. They gain water from the tip of the ghats before they divert to the east coast. Tamil land was forced to develop water harvesting techniques and irrigation pattern, often said to enhance sophisticated „nation building“. Creating, sharing, and planning irrigation water requires administrative and technical skills. The Tamils are masters in it. Go to the Kaveri delta and see for yourself. Cheras, Pandyas and Cholas are names of famous dynasties ruling South India and mastering anything from bronze sculptures to magnificent temples. One of the features of Tamil Nadu is the tank system: half-moon shaped dams on red soil that catch and retain the scarce rain water. Even today, Google Earth reveals this technique from space.

But the rivers of Tamil Nadu depend on inflow generated beyond its borders: Kerala itself, but even more so Karnataka, use as much as they can. There is a water sharing agreement – and a Kaveri Tribunal with the central government in Delhi in case of dispute – but when the monsoon is weak Tamil Nadu loses out. In 2016 the winter (Northeast) monsoon was weak and the rivers did not bring sufficient waters. The granary of Tamil Nadu and the cultural heartland of the Chola dynasty, the Kaveri delta, is dependent on the river water from the Karnataka plateau upstream. A perpetual conflict, never enough water. Farmers from central Tamil Nadu recently staged a desperate protest in Delhi, asking the government to intervene. They begged for their life, quite literally.

As every year, in these May days of 2017 meteorologists, politicians, farmers and millions in India, Nepal, Bangladesh, Sri Lanka, and Pakistan are waiting for the monsoon rains, everyone’s lifeline.

Further sources and information:

Monsoon on Wikipedia

Good Monsoon 2017?, 15 June 2017

Monsoon 2017 early, THE HINDU online 16 May 2017

Southwest monsoon arrival forecast is May 30, two days ahead of schedule

Rainfall deficit in monsoon season 2019, THE HINDU online, 16th June 2019 

Predicting the monsoon. The Hindu online, 30 June 2019

Chennai’s shrinking water supply. The Hindu online, 30 June 2019