South Asia braces for extreme heat as global warming accelerates

Global temperatures continued a sustained rise, with last year identified as the hottest on record and January 2025 opening as the warmest January on record. In a joint assessment, Climate Central and the Red Cross Red Crescent Climate Centre found that climate change has doubled the number of days of extreme heat across 195 countries and territories, underscoring the accelerating pace of heat exposure worldwide.

The findings carry particular urgency for South Asia, a region already marked by densely populated basins where heat can collide with humidity to create dangerous conditions. In southwestern Bangladesh, Munshiganj experienced a heat event described as a 100-year heatwave in April 2024, illustrating how short-term extremes can intersect with long-running trends. Projections paired with current patterns suggest that, even under optimistic scenarios, such heat events will be exceeded in the future on average every six years, a cadence that stretches public health and infrastructure capacities. In parts of South Asia, wet-bulb temperatures—the combined measure of heat and humidity—could reach 35 degrees Celsius (95 degrees Fahrenheit) if global warming continues unabated, a level at which the human body struggles to cool itself through sweating for hours on end.

By 2100, researchers project that roughly 70% of populations in India, Pakistan, and Bangladesh could be exposed to these extreme wet-bulb temperatures. The risk concentrates in densely populated river basins along the Ganges and Indus, where limited access to cooling, water, and health services compounds vulnerability for outdoor workers, the elderly, and families in poverty. The projections highlight the limits of adaptation alone; without substantial emission reductions, the region could face heatwaves far beyond what current health systems are prepared to manage.

Urban areas already show striking heat inequality. Low-income neighborhoods with tightly packed housing, heat-retaining construction materials, sparse green space, and minimal access to cooling capabilities remain several degrees hotter than wealthier districts. In such settings, rolling blackouts, water scarcity, and economic barriers further constrain practical options for residents seeking relief from extreme heat.

To translate projections into action, researchers and policymakers are turning to early warning and adaptation pilots. One notable effort is the JO-CREWSnet initiative—a collaboration between Community Jameel and MIT—that analyzes human systems to identify high-risk hotspots and test practical responses. In southwestern Bangladesh, JO-CREWSnet is testing approaches such as the Adaptation Fortress concept, which envisions shelters equipped with modern cooling technology and powered by solar energy. These shelters would help protect communities not only from cyclones but also from heatwaves, while integrating local skills and resources.

Experts emphasize that adaptation must be paired with aggressive steps to curb carbon emissions. Policy measures called for include expanding green infrastructure, scaling urban and rural cooling projects, and raising building standards to improve thermal performance. The stakes are high: without rapid, concerted action, entire regions could face heat conditions that place unsustainable stress on health care systems, labor productivity, and migration patterns. In short, the climate and health consequences of extreme heat demand immediate, well-funded, and equitable responses that blend forecasting, infrastructure, and emission reductions to reduce risk while supporting vulnerable communities across South Asia.