- GS 1: Changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.
- North East India is showing various vagaries of climate change such as disruptive weather pattern that has stimulated the calamities, which has affected the geography of the region.
- The North East India, which normally receives heavy rainfall during the monsoon months (June-September), has changed character for the worse.
- The flood-drought cycle now has begun to happen within a year, especially during the monsoon.
- Even in the monsoon, the rains come in quick bursts and flood the region, followed by dry periods that leads to drought.
- Between 1989 and 2018, the region has showed a significant decreasing trend in monsoon rainfall.
- Recently, a new scenario was presented in the state where the dry drought-like districts were intermixed with floods due to rainfall in other districts.
- The change in geography from the mountains to the plains is abrupt and steep, which makes the region naturally prone to flooding.
- The number of rainy days decreased in most districts to the north of the Brahmaputra. This means that increased rainfall now happens over fewer days, increasing chances of river flooding.
- The increased flooding observed in Upper Siang and Upper Subansiri rivers may be due to an increase in rainfall.
- Upper Siang shows a significant decreasing trend in the number of rainy days, which translates to more rainfall over fewer days.
- Districts like West Kameng and East Kameng in the western part of the state showed a decrease in the flow of mountain springs and streams in recent decades, which could be due to the decrease in rainfall.
- Here, the gradient of the rivers is not as steep as it is in Arunachal Pradesh, hence the rivers are not as prone to flooding.
- Recent instance of heavy rainfall events, however, have brought floods to places that had not witnessed such calamities in decades.
- North Sikkim showed an increasing trend in monsoon rainfall, which may be causing an increase in flooding in the Teesta River, a tributary of Brahmaputra River.
- This may have led to landslides downstream in South Sikkim, especially around Gangtok, a phenomenon that has been observed since 1997.
- Around 67% of the population of the region is dependent on agriculture, which puts extreme pressure on a small region to feed its entire population.
- Therefore, changing rainfall patterns in the state will impact agriculture, which in turn will affect the state’s food security.
- The state receives 71% of its annual rainfall during the monsoon months.
- The district has flat-topped hills and several rivers, and has seen significant decrease in the number of rainy days.
- The unpredictability of the region can be gauged from the fact that the rainfall in July, the wettest month in the state, had a variability of 40%.
- While the overall rainfall in the 30 years has remained constant, the region has seen a substantial drop in the number of rainy days.
- This has been accompanied with a substantial increase in heavy rainfall days. The region receives 67% of its annual rainfall during the monsoon months.
- The state has seen a decreasing trend over the 30 years, though it is not significant.
- The unique challenge, though, is that all districts now receive fewer overall rains during the monsoon season, which accounts for 60% of its annual rains.