Wednesday, Oct 05, 2022

Climate Change: Excess Rainfall, La Nina Condition Likely To Cause Severe Winter This Year

Global warming impact on weather conditions in India saw prolonged monsoon and excess rainfall in September and October over different parts of the country, particularly the Northwest region.

Representational Image Pixabay

After a prolonged summer monsoon which lasted from June till October 25 this year, giving ample evidence of unusual weather patterns, there are expectations of a severe winter in India due to La Nina conditions.

 The Climate Prediction Center of the National Oceanic and Atmospheric Administration (NOAA), in a recent statement had stated that a La Nina system has formed for the second year in a row. La Nina conditions normally lead to warmer winters in the south and more severe winters in the north.

 Dr M. Mohapatra, director general of the Metrological Department of India, is however cautious, stating that it is too early to forecast the impact of La Nina on severity of winter in north India from December to February.

 “Usually when there is a La Nina condition, the temperature remains low over northern India but there is no direct relationship. The winter forecast from December to February will be issued on December 1,” states Mohapatra. He clarifies that each year sometimes for a day or two the temperature dips around three degree Celsius or even lower in the northern plains including Delhi. At higher altitudes, it is normal for the temperatures to dip much lower to minus degrees.

 Stressing the global warming impact on weather conditions in India, Mohapatra points out that there was excess rainfall in October over different parts of the country, except some parts of the southern peninsula and North eastern states. “The fact is that the temperature is rising all over the globe. Similarly, the temperature is rising all over India, especially in northern India, but that does not mean that every year temperature will rise or every year temperature will fall,” he states.

 The official clarifies that providing the temperature forecast for a station like Delhi three months or four months ahead, carries the risk of never being correct “because that type of modeling system required to provide the location specific forecast three or four months ahead is not there in the world.”

 Even as the developed and developing countries grapple with issues of funding and technology transfer to mitigate impact of climate change and slow down greenhouse gas emissions at the COP26 summit in Glasgow, India is already witnessing extreme weather events. This year, the four months summer monsoon, which accounts for over 80 percent of the rainfall in the country and generally withdraws from the entire country by 15 October, withdrew 10 days late on October 25. The standard deviation is about seven days.

 The changing pattern of monsoon in some parts of the country has taken a toll on the lives of people and cattle stock and also crops due to the intensity of rains in short durations.

 Normally, summer or southwest monsoon starts withdrawing from Northwest India by the middle of September. But this year the withdrawal started on October 6, a delay of about three weeks.

 Northwest India, which has been witnessing lesser rainfall for the past few years, witnessed one of the longer duration monsoons from July 8 to October 6. The monsoon was normal in the southern peninsula. Similarly in central India though the monsoon set in late by about one or two weeks, the duration remained the same due to the late withdrawal.

 The rainfed area of central and northwest India received 6% above normal rain though the country as a whole received 1% below normal rainfall despite the longer duration. More extreme weather events were seen in the months of September and October mainly because of 10 low pressure systems including two cyclones, one depression and remaining low pressure areas. Then there was month to month variation in the monsoon this year. For instance in June and July, when most of the sowing activity takes place, the rainfall was 7% below normal, in August it was minus 24% while September witnessed 35% excess rainfall and in October also there was 32% excess rainfall. The most important event this season was 58 centimeters of rainfall in 24 hours on October of 17 and October 18 in Uttarakhand, leading to landslides.