Extreme weather events have become the new ‘normal’

The message emerging out of last year is loud and clear. Extreme weather events are on a rise in the country and we must plan and prepare for erratic weather patterns that are the new ‘normal’. Almost every month of the last year had one or the other “unprecedented” weather events. We had hailstorms, unseasonal rainfall, strong thunderstorms and lightning, floods and droughts, long dry spells, cyclones, and both our monsoons — southwest monsoon and northeast monsoon — were below normal. Also, average temperature over the country was “significantly above normal”, making 2018 the sixth warmest year on record since 1901.

Early last year, Maharashtra, Chhattisgarh, Madhya Pradesh, Telangana and Uttar Pradesh were hit by unseasonal rains and hailstorms that damaged standing rabi (winter) crops in over 4.76 lakh hectares. Maharashtra is prone to hailstorms, as documented in a countrywide analysis of hailstorms between 1985 and 2015 by the India Meteorological Department’s (IMD) Pune office. But, as scientists at the Met department point out, “From 2013, there is prolonged persistence of hailstorms in the state, causing extensive damage.” Hailstorms now affect a larger area in the state over several days. There are concerns over the increasing size of hail too.

After hailstorms, large parts of the country faced a series of extremely strong thunderstorms and dust storms. Down To Earth, a fortnightly, documented how 44 intense thunderstorms struck over 16 states killing 423 people, which was “unprecedented”. Thunderstorms were accompanied by lightning strikes that destroyed properties and killed people. Data of the National Crime Records Bureau shows the average number of people dying of lightning strikes every year between 2006 and 2015 was about 50 per cent higher than the decade before. Scientists at the Indian Institute of Tropical Meteorology, Pune have examined satellite data between 1990 and 2013 and found a two to three per cent increase in lightning strikes in the country.

Last year witnessed another set of extremities — floods and droughts. Flood and heavy rain-related incidents killed over 800 people during pre-monsoon, monsoon and post-monsoon seasons. In its long-range forecast of the southwest monsoon (June to September) and northeast monsoon (October to December), the Met department had predicted normal monsoon rainfall. However, a ‘below normal’ monsoon rainfall, along with erratic rains induced floods and droughts in several states. For instance, Gujarat, Arunachal Pradesh, Assam, etc., suffered floods during the southwest monsoon season. But, these states are now staring at an acute drought. Several other states — Bihar, Jharkhand, Andhra Pradesh, Maharashtra, etc — have officially declared a drought too. Also, the last northeast monsoon rainfall has been “substantially below normal” and sixth lowest since 1901.

M Rajeevan, secretary, Union ministry of earth sciences, rightly points out that 2018 has been a year of many disasters. And as global warming continues, there should be an increase in frequency of these disasters because of larger variability on both the sides. Therefore, we should expect more floods as well as more deficient rains (droughts), and need to prepare for such a state of climate.

 Interestingly, in spite of both monsoons being deficient, 15 depressions and four cyclones hit the Indian coast last year. There are several research studies that link changing climate to an increasing frequency of intense tropical cyclones in the north Indian Ocean. Data of 122 years of tropical cyclone frequency over the north Indian Ocean from 1877 to 1998 shows “there is indeed a trend in the enhanced cyclogenesis during November and May”. There has been a two-fold increase in the tropical cyclone frequency over the Bay of Bengal, a 17 per cent increase in the intensification rate of cyclonic disturbances to the cyclone stage, and a 25 per cent increase to severe cyclone stage over the north Indian Ocean during November in the past 122 years, the study noted.

Analysis by Down To Earth suggests that extreme weather events have increased from just one during 1900-1910 to 61 during 1971-80. And that number almost tripled to 162 during 2001-2010.

Whereas no single extreme weather event can be attributed to climate change, it is also true that the increased frequency and intensity of these extreme events are due to human-induced climate change. Extreme rainfall, extreme heat, extreme thunderstorms, extreme cold waves, extreme tropical storms are the new “normal”. And we need adaptation strategies and disaster response plans to face exigencies arising out of this new ‘normal’.

The author is an independent journalist