Q. Which of the following factors is/are possible factors behind changing rainfall pattern in North East India?
1. Drying up of land due to climate change.
2. Increased snowfall in the Eurasian region.
3. Pacific decadal Oscillation.
Select the correct answer from the codes given below:

[A] 1 and 2 only

[B] 2 and 3 only

[C] 1 and 3 only

[D] 1, 2 and 3

Answer: D

Climate change is causing increased variability and unpredictability of rainfall in the North East region of India. 

  • Climate change causing drying up of land: An aspect of warming that influences rainfall is drying of the land, which increases the frequency and intensity of dry periods and droughts. An increase in moisture and the drying up together change the rainfall patterns in unpredictable ways. 
  • Increased snowfall in the Eurasian region also impacts monsoon rainfall in North East India. Excessive snowfall in Eurasia causes cooling of the atmosphere of the region, which triggers events eventually leading to a weak summer monsoon season there. 
  • Sea surface temperatures: A study has also attributed a decrease in rainfall to sea surface temperatures over the subtropical Pacific Ocean, which vary in a cycle and each phase of which lasts a decade. The peak comes every 20 years and is known as the Pacific Decadal Oscillation (PDO). As per a study, PDO is being influenced by global warming as it decreases the difference of temperatures among the layers of the ocean. The peak of PDO will change from 20 to 12 years, which may have an impact on the monsoon rainfall in North East India. 

Source: Article