Ministry of Earth Science

Changing Rainfall Pattern in the Country

Posted On: 09 FEB 2021 5:18PM by PIB Delhi

India Meteorological Department (IMD) has carried out an analysis of observed monsoon rainfall variability and changes of 29 States & Union Territory at State and District levels based on the IMD’s observational data of recent 30 years (1989- 2018) during the Southwest monsoon season from June-July-August-September (JJAS). The reports on observed rainfall variability and its trend for each State and Union Territory are available in IMD website (https://mausam.imd.gov.in/) under “PUBLICATIONS” as well as in IMD Pune website

http://www.imdpune.gov.in/hydrology/rainfall%20variability%20page/rainfall%20trend.html

The detailed report is given in Annexureand the highlights of the report are as follows:

    • Five states viz., Uttar Pradesh, Bihar, West Bengal, Meghalaya and Nagaland have shown significant decreasing trends in southwest monsoon rainfall during the recent 30 years period(1989-2018).
    • The annual rainfall over these five states along with the states of Arunachal Pradesh  and Himachal Pradesh also show significant decreasingtrends.
    • Other states do not show any significant changes in southwest monsoon rainfall during the sameperiod.
    • Considering district-wise rainfall, there are many districts in the country, which show significant changes in southwest monsoon and annual rainfall during the recent  30 years period(1989-2018).
    • With regard to the frequency of heavy rainfall days, significant increasing trend is observed over Saurashtra & Kutch, South-eastern parts of Rajasthan, Northern parts of Tamil Nadu, Northern parts of Andhra Pradesh and adjoining areas of Southwest Odisha, many parts of Chhattisgarh, Southwest Madhya Pradesh, West Bengal, Manipur & Mizoram, Konkan & Goa andUttarakhand.

The Ministry of Earth Sciences (MoES), Government of India has recently published a Climate Change report entitled "Assessment of Climate Change over the Indian Region" which covers all the aspects of regional climate change including the climatic extremes across India. The preparation of this report was led by the Center for Climate Change Research (CCCR) at the Indian Institute of Tropical Meteorology (IITM) Pune. The report from the MoESis the first of its kind where a comprehensive discussion has been made regarding the impact of human-induced global climate change on the regional climate and monsoon of the Indian subcontinent, adjoining Indian Ocean and the Himalayas. Based on the available climate records, the report documents that the surface air temperature over India has risen by about 0.7 °C during 1901–2018 which is accompanied with an increase in atmospheric moisture content. The sea surface temperatures in the tropical Indian Ocean have also increased by about 1 °C during 1951–2015. Clear signatures of human-induced changes in climate have emerged over the Indian region on account of anthropogenic greenhouse gases and aerosol forcing, and changes in land use and land cover which have contributed to an increase in the climatic extremes. The complex interactions between the earth system components amidst the warming environment and regional anthropogenic influences have therefore led to a rise in frequency of localized heavy rainfall events, drought and flood occurrences, and increase in the intensity of tropical cyclones etc. in the last few decades. Also, recent studies by Indian Scientists reveal that the trends in sea level rise are estimated to be 1.3mm/year along the Indian coasts during the last 40-50years.

This information was given by the Minister of Science & Technology; Earth Science and Health & Family Welfare Dr. Harsh Vardhan in the Rajya Sabha today.

 

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