New Delhi: The 2021 south-west monsoon is entering its final leg, but over its first three months — June, July and August — it has proven to be erratic across India. The country has witnessed two major breaks in the monsoon — one each in July and August — as a result of which the overall amount of rainfall is below average.
The pattern of this year’s monsoon fits what a 9 August report by the Intergovernmental Panel on Climate Change (IPCC) had predicted — due to climate change, there is likely to be a “lengthening of the monsoon” along with an increase in monsoon extremes such as heavy rainfall, floods and droughts.
These extremes were visible early in June when intense thunderstorms led to 10 per cent more rainfall than the Long Period Average (LPA), which is the current benchmark used to measure the phenomenon. LPA is the average rainfall received between 1961 and 2010.
However, in July, the first 11 days saw a ‘break’ in the rains. A ‘break’ occurs when the monsoon is interrupted by long spells of deficit rainfall in the majority of the country. Even after the ‘break’, for 10 days till 21 July, the monsoon continued to be weak, which means sporadic rainfall occurred but remained below normal. This led to the average rainfall across the month registering at 93 per cent of the LPA.
Then came another break in the first half of August. Because of this, the all-India figure till the end of August was 91 per cent of the LPA.
Similar story in different regions
Over 20 of the 36 meteorological subdivisions across India witnessed below-average rainfall this season.
According to data from the India Meteorological Department (IMD) website, states in the Northwest region — Uttar Pradesh, Uttarakhand, Punjab, Himachal Pradesh, Jammu and Kashmir and Rajasthan — witnessed extremes of rainfall, from 226 per cent of the LPA on 2 June to 114 per cent on 30 June, to 85 per cent on 14 July and 88 per cent of the LPA on 25 August. Haryana, Chandigarh and Delhi have reported above-average rainfall.
In the Central region too — consisting of Odisha, Gujarat, Madhya Pradesh, Maharashtra and Chhattisgarh — the monsoon was irregular. Until 16 June, this region had registered 162 per cent of the LPA, but by 25 August, the figure had hit 87 per cent. A shortfall began on 7 July but by the 28th of the month, the rains had hit surplus levels, before falling again.
The East-Northeast region reported below-average rainfall from 7 July, when the figure stood at 98 per cent of the LPA. By 25 August, the figure had hit 89 per cent.
In the South region, the monsoon was consistently above the LPA for the first couple of months — 104 per cent at the end of June, and 122 per cent in July. However, it declined to 103 per cent by the end of August.
According to the IMD data, Gujarat, Rajasthan, Punjab, Odisha, Kerala and the Northeast have borne the brunt of deficient rainfall, and thus, the likelihood of drought over Gujarat and western Rajasthan has increased.
The erratic monsoon rainfall this year has also resulted in a drop water storage levels in major reservoirs across the country. According to a Central Water Commission bulletin dated 26 August, the overall water level in 130 reservoirs across the country is just 83 per cent of the figure registered last year, and 96 per cent of the last 10 years’ average.
This data further shows just how dry August was, since on 29 July, the bulletin had shown a level of 121 per cent of last year, as well as 121 per cent of the average of the last 10 years.
‘Normal’ forecasts, abnormal rainfall
The south-west monsoon, which is crucial to the economy of the country owing to its impact on agriculture, was originally forecasted to be normal by both the IMD and Skymet, one of India’s largest private weather monitoring and forecasting companies, which also provides agri-risk solutions.
“Monsoon rains have been a bumpy ride this year and aren’t on expected lines. June was a surplus and even the deviation in July was as expected, with rainfall on the lower side. The shock came in August — which was expected to do better with 99 percent of average rainfall, but for most of the month, ‘break’ conditions remained. The rainfall for August has been short by around 25-26 per cent, which will be a record,” Skymet president G.P. Sharma told ThePrint.
“The present shortfall in monsoon can be attributed to the negative threshold of the Indian Ocean Dipole, which is known to cause below-normal rainfall. We have revised our forecast to below-normal now, to 94 per cent with a margin of 4 per cent,” Sharma added, explaining the reasons for these patterns.
“The situation has not been good in August in most parts. Gujarat, Maharashtra and Rajasthan have had very large rainfall deficiency, along with some dip in Odisha, MP, Chhattisgarh and the Northeast. There were also extreme rainfall events along with the west coast and UP in June. In July, extreme events occurred in western MP, Maharashtra and Karnataka, leading to floods,” D.S. Pai, IMD’s head of climate research and services, said in a webinar.
“In the next few weeks, there’ll be an improvement in rainfall activity in the central and northwestern regions. We are expecting rainfall in these regions in September-October, on account of delayed withdrawal of monsoon, which we’ve seen for the last 10-12 years.”
Skymet’s Sharma said the impact of climate change is clear in these patterns.
“Climate change is a reality and monsoon is also a large-scale global phenomenon. The high-impact weather event frequency is increasing, causing uncertainty. In the last three decades, monsoon rainfall has decreased. However, that doesn’t mean rainfall will decrease every year — in the last three years, the monsoon has brought above-normal rainfall,” he said.
ThePrint had also reported that low rainfall and reservoir levels are likely to damage food production, pushing inflation and also threatening power production.
(Edited by Shreyas Sharma)