Poring over pouring monsoon data

Last week, India received rains it had been waiting for all of June, when the monsoon typically makes landfall. Large parts received intense downpours, more than halving the cumulative seasonal deficit that had climbed to a worrying 40%.

On the face of it, this was a welcome turnaround. Yet, the rains also exposed a deeper problem: they arrived all at once, instead of being staggered as is the norm. These periods of intense bursts of rainfall interspersed with prolonged dry spells are gradually becoming the new normal. So, the basic assumption about the progress of the monsoon, which accounts for over 80% of India's annual precipitation, appears to be broken.

Without predictability, weather patterns are now a lottery. This means the assumed relationship between agriculture and industrial demand can't be taken for granted. As a result, a volatile climate and extreme weather make farming that much riskier, and managing industrial demand that much more unpredictable.


Consequently, watching the shrinking or widening cumulative rainfall deficit would be a case of missing the wood for the trees. Worse, the growing frequency of extreme weather events is testing the ability of urban India and its new, big-ticket economic infrastructure to withstand such shocks.

According to an Indian Institute of Tropical Meteorology (IITM), Pune, study, there has been a staggering 3x rise in widespread extreme rain events over India during the 65 yrs leading up to 2015. Similarly, data compiled by Centre for Research on the Epidemiology of Disasters reveals that instances of extreme weather have gone up almost 5x - from 71 in the 1970s to 350 in the first decade of the millennium.

Anecdotal evidence suggests that this situation has only gotten worse. For example:

2010 Cloudburst over Leh caused immense damage.

2013 Unprecedented, continuous rainfall and cloudbursts from June 15 to 17 in the higher reaches of the Himalayas in Uttarakhand caused Chorabari Lake in Rudraprayag to spill over and inundate Kedarnath.

2014 Prolonged rainfall across Kashmir Valley in early September caused Jhelum to overflow, all but drowning Srinagar.

2018 Kerala witnessed its worst floods in 100 yrs, displacing an estimated 1 mn people and causing unprecedented devastation. One trigger was excess rain - 250% above normal.

Extreme rain events are not unique to India. Researchers estimate that global economic losses from floods exceeded $30 bn a year in the past decade, with some of the largest losses linked to extreme rainfall events occurring in Asia.

'Floods attributed to extreme rain events in India alone accounted for losses of about $3 billion per year, which is 10% of global economic losses. In our study, we demonstrate that these floods are on the rise due to the occurrence of widespread extreme rains. We find a threefold increase in these widespread extreme events during 1950-2015,' the IITM study noted.

Worryingly, the study reveals that average precipitation during the annual monsoon over India has been steadily decreasing since 1950, even while extreme rainfall events are increasing. Undoubtedly, this is a structural shift. In other words, prolonged dry phases during the monsoon are interspersed with short spells of heavy downpours, causing large-scale damage.

Merely tracking the cumulative rainfall deficit number will miss the worrying pattern of rising extreme rainfall events and their attendant consequences. A UN disaster atlas confirms the conclusions of the IITM study that Asia seems to bear the brunt of extreme weather. It estimates that between 1970 and 2019, 3,454 disasters were recorded worldwide, with 9,75,622 lives lost and $2 tn reported in economic damages. Asia accounts for nearly a third of climate- and water-related disasters globally, nearly 50% of all deaths, and 1/3rd of associated economic losses. 45% of these disasters were associated with floods and 36% with storms.

According to the IITM study, the consequences of extreme rainfall in India impact 500 mn people - a third of India's population and more than the entire population of the US. Geographically, the most impacted region is the central belt of India - Gujarat, Maharashtra, Madhya Pradesh, Chhattisgarh, Telangana, Odisha and Jharkhand - alongside Assam, Meghalaya and parts of Western Ghats (Goa, North Karnataka and south Kerala).

The policy challenge is no longer only about managing and estimating rainfall but also about managing uncertainties, such as the increasing frequency of extreme rainfall. This is the moment for India to revisit accepted paradigms about the monsoon, just as it has done with accepted wisdom regarding its social policy.