Guwahati: All the eight states in the Northeast will witness an increase in temperature, an increase in the number of rainy days and a rise in the number of heavy rainfall activities over the next three decades (2021–2050) compared to the historical period (1990–2019), a latest study reported has stated.
The report, titled ‘District-Level Changes in Climate: Historical Climate and Climate Change Projections for the North-Eastern States of India’, released by the Center for Study of Science, Technology and Policy (CSTEP), has predicted changes in temperature and rainfall patterns in Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, and Tripura over the next three decades.
CSTEP is a Bengaluru-based think tank, which carried out the study on the climate of Northeast India.
It analyzed two representative scenarios: moderate emissions (RCP 4.5) and high emissions (RCP 8.5).
According to the study, temperature and rainfall have increased, and rainfall variability is high across all the North-eastern states during the last two decades from 1990 to 2019.
Climate change projections by CSTEP indicate overall warming of both summer and winter minimum temperatures, an increase in the number of rainy days (>2.5 mm rainfall/day), and an increase in the number of heavy rainfall events across almost all the districts of the north-eastern states.
Summer maximum and the winter minimum temperatures are projected to increase by 1°C to 1.5°C under the RCP 4.5 scenario and 1°C to 2°C under the RCP 8.5 scenario, it said.
The winter minimum temperature is projected to increase largely by 1°C to 1.5°C under the RCP 4.5 scenario and 1°C to 2°C under the RCP 8.5 scenario in a majority of the districts of the Northeast, the report added.
The number of rainy days is projected to increase in the 2030s in all the districts in the Northeast compared to the historical period. The increase is by 1 to 24 days under the RCP 4.5 scenario, with the maximum increase projected in Sikkim and a minimum increase projected in Assam. The increase is by 1 to 22 days under the RCP 8.5 scenario, with the maximum increase projected in Sikkim.
The report mentioned that rainfall during kharif (June to September) and rabi (October to December) seasons is likely to increase in the 2030s in almost all the districts of Northeast India compared to the historical period.
An increase in high-intensity (51–100 mm/day) and very high-intensity (>100 mm/day) rainfall events is projected in the 2030s across all the districts of the Northeast compared to the historical period.
The increase in high-intensity rainfall events per annum is by one to four events under the RCP 4.5 scenario and one to five events under the RCP 8.5 scenario, it pointed out.
A decline in rainfall deficient years is projected in the 2030s across almost all the districts of north-east India compared to the historical period.
The decline in rainfall deficient years is by 1 to 4 years out of 30 years under the RCP 4.5 scenario and 1 to 5 years under the RCP 8.5 scenario in the various districts of Northeast India.
Climate projections for the north-eastern states at the district level for the period 2021–2050 (the 2030s) indicate a warmer and wetter future with an increase in heavy rainfall events.
According to the study, the heavy rainfall events are projected to be more frequent and more intense, and the projections are largely in agreement with the literature available at the global, South Asia, and national levels.
The full report is available here.