This is the eighth consecutive year that India’s monsoon rains have been broadly within the normal range. But behind these numbers are regional and daily variations. Climate change is one reason for this.
This year’s monsoon ended with 94 percent of total rainfall, marking the eighth consecutive year that seasonal rainfall has been broadly within the normal range. It seems that the monsoon has been remarkably consistent in the country in recent years. However, there are large differences in the distribution of rainfall, both spatially and temporally. Some days have very heavy rains, but long periods are very dry. Similarly, most of the districts received very little rainfall during most of the seasons. This rainfall variability appears to be increasing due to climate change.
Normal rainfall is widespread in the district. During the four-month monsoon season, the districts have very few occurrences of normal daily rainfall. A new analysis by a research organization, Climate Trends, has found that it is a rare occurrence for counties to receive normal daily rainfall. Out of nearly 85,000 district rain days, 121 days in 718 districts saw only 6 percent of normal rainfall.
In contrast, more than 60 percent of the daily district-wise rainfall showed a deficit of more than 60 percent or no rainfall at all on rain-expected days. The analysis also showed that districts with more days of 60 percent or more rainfall than normal had the next highest number of events.
Meanwhile, experts say, “Normal rainfall data is averaged over years and cannot be expected to indicate uniformity of rainfall, but the relatively low number of normal rainfall days experienced by 718 districts in India reflects the oscillation between extremes.”
The season produced the second largest series of extreme rain events in the past five years, which offset the lack of dry days and brought an illusion of normalcy. Rainfall showed large variations even in the dry northeast and Kerala at the regional level. The North-West and Central regions of the country have received more than 100 per cent rainfall this season,
while the East and North-East regions have received only 80 per cent. The southern part of the country also experienced major deficits during most of the monsoon season. The region finally finished with 92 percent rainfall for the season. Deficiency over East and Northeast India reinforces the long-term trend of normal rainfall in the region. As indicated by climate trends analysis, the region has received less than 100 percent rainfall in nine of the previous 10 years.
monsoon
In five of those cases, the deficit is more than 10 percent. This region, at least the north-east, traditionally receives high rainfall. The states of Bihar, Jharkhand and West Bengal received particularly poor rainfall this year, each ending up with a deficit of more than 20 per cent. The states of Nagaland, Manipur, Mizoram and Tripura also have a deficit of more than 20 percent. Kerala is one of the rainiest states in the country, but this year it ended up with a deficit of 34 percent. Not only during the monsoons, rainfall in Kerala has been declining for the past few years. 132.7 cm this year is the highest in the last 12 years. So the rain has decreased.
Climate Change
The increasingly erratic behavior of monsoons is commonly blamed on climate change but it is not that simple. There are many other factors at play. For example, this year’s monsoon was expected to be hit by El Niño in the eastern Pacific Ocean. El Niño events in previous years have caused major rainfall deficits during monsoons. However, this year’s rainfall has not been affected, at least on an overall scale. A prolonged cyclone on the West Coast in June and very heavy rainfall in the northern states in July helped offset El Niño’s rain-suppressing impact.
monsoon rainfall
August seemed to be under the influence of El Nino. In fact, it produced only 64 percent of rainfall, the driest August on record. But despite El Nino strengthening, September again brought good rains. Climate change has introduced a greater degree of uncertainty in weather events. Even if some drastic measures are taken to immediately reduce greenhouse gas emissions, which are known to be the cause of global warming and climate change, the unpredictability of monsoons will continue. In this context, disaster preparedness activities will be given greater emphasis to eliminate disruptions that could exacerbate the impacts of extreme weather events on urban flooding. For example, strengthening climate resilience in new and old infrastructure are some of the areas expected to receive increased attention.
