Climate crisis, land-use change ruining ecology: Experts on Uttarakhand flash flood
Dehradun: The rain in Nainital and adjoining districts on Monday and Tuesday that caused flooding in eastern Uttarakhand, leaving 34 people dead, was the heaviest ever recorded in the region, and another indication that the loss of local ecology due to the climate crisis and changes in land-use patterns has started wreaking havoc on the Kumaon hills.
Nainital’s Mukteshwar area reported 340.8mm rainfall 24 hours between 8.30 am on Monday and 8.30 am on Tuesday, the highest since the weather station was set up there in 1897. Before Tuesday, the highest rainfall of 254.5mm was reported on September 18, 1914.
“Apart from Mukteshwar, the rainfall has also broken records in Pantnagar in Udham Singh Nagar district, which had reported rainfall of 228mm on July 10, 1990, has now in the last 24 hours, received 403.9mm rainfall,” said director of the meteorological centre Dehradun Bikram Singh.
According to India Meteorology Department data, the state reported 178.4mm rain in first 18 days of October — 485% more than the average. In the last 24 hours starting on Tuesday morning, districts such as Chamoli and Udham Singh Nagar received around 10,000% more rain than the average. Over the last 24 hours, Chamoli has reported 127.5 mm rain, against the average of 0.6 mm; while US Nagar reported 232.1 mm rainfall against the average of 1.6mm.
Singh attributed the spurt in extreme rainfall events in the area to the climate crisis, saying that heavy rainfall in short spells has increased in the state -- a phenomenon that has been confirmed by various studies conducted by IMD and the Indian Institute of Tropical Meteorology between 2016 and 2020.
To be sure, this is in line with the rainfall patterns recorded across the country in recent years.
According to IMD, Uttarakhand has reported over 7,750 extreme rainfall events and cloudbursts since 2015 -- a majority of them in the last three years. An extreme rainfall event is recorded when a location receives more than 204 mm of rain in 24 hours.
Till July this year, the state reported 979 extreme rainfall events. In 2020, this number was 1,632 for the whole year, and went as high as 3,706 in 2018.
Weather experts, however, said that the actual number of cloudbursts or extreme rainfall events in Uttarakhand must be much higher but most areas don’t have weather stations to record them.
“Officially, this year we recorded three cloudbursts -- in Haldwani, Champawat and Dehradun. Traditionally, cloud burst is defined as over 100mm/hour within a limited geographical area of a few square kilometres. But we have only 25 weather observatories in the state. The state has set up 107 observatories, but more such measuring stations are required to get near to the exact numbers,” Singh said.
Experts say that although the climate crisis was causing extreme rainfall, destruction of local ecology, unplanned development, and unscientific road cutting also contributed to the weather events, which have claimed over 4,000 lives since 2014, and been the cause of 1,961 major landslides in the last seven years.
They attributed this to major development projects in higher reaches of the Himalayas, especially hydel power projects; encroachment of seasonal streams; and population growth, which has led to the proliferation of construction activities in narrow valleys, often in close proximity of rivers and rivulets.
Nainital, for example, has over 7,000 structures on its slopes around the Nainital lake -- up from 520 in 1901-02.
Experts say the increase in rain-induced landslides in the state has also been due to road-cutting, the unscientific disposal of muck, illegal mining activities, increase in hill agriculture, and no significant increase in the forest cover of the state to compensate for these activities. In the last two surveys conducted by the Forest Survey of India, over a period of four years from 2015 to 2019, Uttarakhand did not manage to report even a 1% increase in forest cover.
“There are human factors which are aggravating the human loss in such events. We are cutting trees for development projects, we are cutting hills and destabilising slopes by cutting hills for roads, we have built hydel power projects in fragile Himalayan valleys, we are mining river beds discriminately. All these factors also contribute to the changes in the Himalayan ecology,” Anil Joshi, founder of Himalayan Environmental Studies and Conservation Organization, a Dehradun-based NGO said.
DP Dobhal, a noted glaciologist and retired scientist from Wadia Institute of Himalayan Geology (WIHG), said that the impact of the climate crisis on the rainfall and snowfall patters in the Himalayas was clearly visible. “The Himalayas are witnessing less snow compared to the past but simultaneously rainfall is ascending higher into the Himalayas. When more rain meets steep terrain, it results in higher precipitation and quicker funneling of water downstream, which creates flash floods and flooding in general,” he said.
Dobhal added that, over the last 50 years, the snowline has gone up from nearly 4,800 metres to 5,200 metres. “Also due to climate change, the average temperature has risen by 0.3 to 0.6 degrees Celsius in the Himalayas in the last 100 years or so.”