By Safia Noor
South Asia is facing an increasingly volatile climatological regime, where interannual weather variability is being strongly modulated by interactions between the El Niño–Southern Oscillation (ENSO), Indian Ocean sea surface temperature anomalies, Himalayan cryosphere dynamics, and anthropogenic climate forcing. The transition from neutral or weak La Niña conditions towards a probable El Niño phase during 2026 raises serious implications for regional precipitation distribution, thermal extremes, hydrology, agricultural productivity, and disaster risk management. ENSO is a coupled ocean–atmosphere phenomenon originating in the equatorial Pacific, characterised by periodic warming (El Niño) or cooling (La Niña) of central and eastern Pacific sea surface temperatures.
These anomalies alter Walker Circulation patterns, upper-level divergence, and tropical convection, producing large-scale teleconnections that significantly influence South Asian climate. During El Niño, positive Sea Surface Temperature (SST) anomalies in the Niño 3.4 region weaken easterly trade winds, reduce convection over the western Pacific, suppress monsoonal circulation, weaken the South Asian summer monsoon trough, delay monsoon onset, and reduce seasonal precipitation. These processes enhance atmospheric subsidence over Pakistan and north-western India, increasing the probability of heatwaves and drought. In contrast, La Niña conditions strengthen Walker Circulation through negative SST anomalies, intensify convection over the Indo-Pacific warm pool, strengthen monsoon circulation, and often generate above-normal precipitation, thereby elevating flood risks across the Indus and Ganges basins.
ENSO impacts are spatially heterogeneous across South Asia. Pakistan’s northern regions may experience altered western disturbance patterns, while southern areas, particularly Sindh and Balochistan, often face amplified temperature anomalies and rainfall deficits during El Niño episodes. Current climate models from the World Meteorological Organization, NOAA, ECMWF, and the Pakistan Meteorological Department indicate an elevated probability of El Niño development during the 2026 monsoon cycle. This suggests above-normal land surface temperatures across Pakistan, India, Bangladesh, and Afghanistan, alongside suppressed southwest monsoon intensity, reduced rainfall over critical agricultural zones, increased evapotranspiration, elevated irrigation stress, and potential reservoir deficits in key water systems such as Tarbela and Mangla.
In this context, Pakistan’s pre-monsoon heatwave profile is already intensifying due to persistent subtropical high-pressure ridging, urban heat island amplification, reduced soil moisture feedback, and aerosol–climate interactions. This thermal escalation compounds hydrological vulnerabilities, particularly as Pakistan’s water systems are fundamentally dependent on snowpack accumulation, glacier melt from the Himalayan–Karakoram–Hindu Kush system, monsoon rainfall, and western disturbances. ENSO variability significantly influences the timing of snowmelt, seasonal river discharge, flood pulse synchronization, and groundwater recharge. Under El Niño conditions, reduced monsoon recharge combined with higher glacier melt from extreme temperatures can create short-term elevated river flows, masking long-term water deficits.
Simultaneously, thermal destabilization increases the risk of glacial lake outburst floods (GLOFs), creating what may be described as a hydrological paradox: temporary water abundance obscuring deeper structural scarcity. Agriculturally, South Asia’s food systems remain deeply monsoon-sensitive despite modernization efforts. Wheat production faces terminal heat stress, rice yields may decline under rainfall deficits, and cotton in southern Punjab and Sindh becomes increasingly vulnerable. Additional pressures include pest outbreaks linked to thermal anomalies, soil moisture depletion, and salinity intrusion in the lower Indus basin. The broader consequences include lower agricultural GDP, rising food inflation, increased import dependency, destabilized rural livelihoods, and intensified stress across the food–water–energy nexus.
Anthropogenic climate change is amplifying ENSO’s baseline effects through increased atmospheric moisture-holding capacity, rising marine heatwave frequency in the Arabian Sea and Bay of Bengal, intensified tropical cyclone potential, more severe heatwaves, and increasingly volatile precipitation patterns. Consequently, El Niño years are becoming hotter and drier, while La Niña years are becoming wetter and more flood-prone. This non-linear amplification has already manifested in Pakistan’s 2022 and 2024 floods, record-breaking heatwaves during 2024–2025, and increasingly erratic monsoon distribution patterns.
It is perceived that climate variability is now intersecting directly with national security concerns, including water governance, energy security, agricultural sustainability, public health, migration, and macroeconomic resilience in Pakistan. Technical adaptation priorities therefore require expanded high-resolution seasonal forecasting, ENSO-informed monsoon modelling, satellite hydrometeorological monitoring, dynamic reservoir optimization, glacier monitoring systems, managed aquifer recharge, climate-resilient seed systems, precision irrigation, heat-resistant crop development, wet-bulb monitoring, heat action plans, and resilient urban power infrastructure capable of meeting escalating cooling demands. Pakistan and South Asia are confronting a climate regime in which ENSO variability is no longer an isolated cyclical phenomenon, but a force increasingly magnified by global warming, cryospheric instability, and socioeconomic vulnerability.
The likely emergence of El Niño in 2026 poses serious threats to monsoon reliability, food security, water availability, public health, and macroeconomic stability. In technical terms, the region is transitioning from climate variability to climate instability. The policy challenge is therefore no longer limited to forecasting ENSO phases, but rather integrating climate intelligence into national planning frameworks capable of managing compound, cascading, and systemic environmental shocks. For South Asia, long-term resilience will depend on whether climate science can be translated rapidly enough into infrastructure modernization, governance reform, and adaptive capacity before climate variability evolves into a sustained regional crisis.
(The writer is a research officer at National Institute of Maritime Affairs, Karachi. She is an MS scholar pursuing her master’s degree in the Department of Earth and Environmental Sciences at Bahria University, Karachi. She can be reached at editorial@metro-morning.com)
