Journal of Earth Sciences, Geology and Geospatial Research

(Annual (One issue per year))

ABSTRACT

El Niño–Southern Oscillation (ENSO) remains the dominant source of interannual climate variability affecting the Indian subcontinent, yet its statistical relationship with the Indian Summer Monsoon Rainfall (ISMR) has weakened markedly since the 1980s, even as the frequency and severity of associated extreme weather events heatwaves, deficit and erratic monsoons, and compound flood-drought sequences has intensified. This paper presents a systematic, PRISMA 2020-guided review and structured narrative meta-analysis of 27 peer-reviewed and institutional studies published between 2010 and 2026 to (i) characterise present-day trends linking El Niño phases to extreme weather across India, (ii) critically appraise the quality, confidence levels, and data gaps of the existing evidence base, and (iii) project future climate risk under CMIP6 Shared Socioeconomic Pathway (SSP) scenarios. Findings indicate a robust post-El Niño heat-extreme amplification, reported in all reviewed heat-extreme studies; a regionally heterogeneous and weakening core-zone monsoon teleconnection, reported in the majority of monsoon studies; and consistent agricultural yield penalties of 3–20% for rice, maize, pulses, and groundnut during El Niño years. The year 2024 - the warmest on record for India since 1901 - is used as an illustrative present-day case, during which heatwave conditions were recorded on 54 of 92 pre-monsoon days and more than 3,000 deaths were attributed to combined extreme-weather events nationally. The review concludes with six ranked, policy-relevant recommendations spanning early-warning systems, heat-health governance, agricultural risk transfer, and long-term adaptation financing, intended to support government planning under conditions of rising climate risk and weakening seasonal predictability.

Keywords: El Niño-Southern Oscillation; Indian Summer Monsoon; Heatwaves; Climate Extremes; CMIP6 Projections; Climate Risk; India; Agricultural Drought; Systematic Review; Meta-Analysis; PRISMA 2020