Sri Lanka is an island nation renowned for its lush landscapes and temperate climate. But this tropical beauty is now confronting an escalating heat crisis. Recent years have witnessed unprecedented temperature surges, with April 2023 marking a significant peak. The Department of Meteorology reported daily maximum temperatures soaring to 36°Celsius(°C), a rise of approximately 3°C above the usual averages (Climate Fact Checks, last year [2024]). 

This intensifying heat not only disrupts daily life but also poses severe threats to public health, agriculture, and the nation's economy. Far from being an isolated spike, this temperature anomaly marked yet another milestone in a disturbing trend that experts say has been accelerating steadily for decades. And, with every degree that rises, the crisis deepens. It is now showcasing an increasingly uncomfortable truth that needs immediate intervention: Sri Lanka is heating up, and fast.

To gain an in-depth understanding of the gravity of Sri Lanka’s dire predicament, one must first unpack the mechanics behind its rising temperatures. The forces at play may seem unrelated but are deeply intertwined.

The science behind the heat

Several interrelated factors contribute to Sri Lanka's intensifying heat:

• Climate change: According to a 2023 report by Mongabay, Sri Lanka’s average temperatures are increasing at nearly 1.8°C per decade, outpacing many global averages. This trajectory places the nation squarely in the crosshairs of anthropogenic climate change, largely driven by fossil fuel combustion and deforestation. Greenhouse gases trap heat within the Earth’s atmosphere, creating a feedback loop that exacerbates regional climate anomalies. In Sri Lanka’s case, the tropics amplify these effects leading to the scorching effect.

• The El Niño phenomenon: Compounding the manmade crisis was the 2023 El Niño event, a cyclic warming of the Pacific Ocean that disrupts atmospheric circulation across the globe. Its fingerprints were clearly visible across South and Southeast Asia, including Sri Lanka. Reduced cloud cover and altered jet streams meant more direct solar radiation reached the land surface, intensifying the nation’s already sweltering conditions. The rising heat across the globe only serves to amplify this effect.

• Urban heat islands: In cities like Colombo, Kandy, and Jaffna, another enemy lurks: urban heat islands. As green spaces give way to concrete, asphalt, and glass, heat becomes trapped and re-emitted by buildings and roads. The World Bank (2020) reported that Colombo's urban heat islands effect can make some areas 5°C hotter than neighbouring rural zones, creating microclimates that are unlivable during peak afternoons. Colombo’s green cover as well across the country has significantly reduced over the past few years, requiring constant cooling through air-conditioning and other energy driven mechanisms comparable to just a decade ago.

The implications of rising heat stretch far beyond discomfort. Heat stress has now become a public health emergency with far-reaching consequences.

• Health risks: Increased cases of heat stroke, dehydration, and the exacerbation of chronic illnesses have been reported. The elderly, young children and outdoor workers including construction workers are seen to be more vulnerable to these effects. 

• Economic strain: Sri Lanka's economic backbone – agriculture – has been hit particularly hard. Tea, rice, and vegetable production have suffered significant losses due to crop stress, delayed monsoons, and depleted water tables. In 2024, the paddy harvest in the Polonnaruwa District dropped by 25%, driving food prices up and triggering warnings of food insecurity.

• Educational disruptions: Extreme heat has led to the postponement of school activities and reduced attendance, affecting educational outcomes. Heat guidelines were issued to schools by the Ministry of Education to prevent students from engaging in outdoor activities due to the extreme temperatures, citing potential risks of heat cramps, strokes and exhaustion.

• Trade and tourism: Overheating would lead to tourists being attracted to more palatable conditions in terms of temperature as the cooling costs in the country would also lead to higher rates for the maintenance of malls and hotel spaces.

Environmental consequences

Beyond human health, the environment too bears the challenges of rising temperatures:

• Biodiversity loss: Heat stress affects wildlife, leading to shifts in species distribution and behaviour, and in some cases, mortality. Rising temperatures disrupt the delicate balance of Sri Lanka’s biodiversity. Endemic species such as the purple-faced langur and the Sri Lankan leopard are seeing shifts in their habitat ranges. In addition, accelerated algae blooms would result in the critical loss of fish and related species in water bodies.

• Water scarcity: Higher temperatures mean higher evaporation rates. Reservoirs, especially in the dry zones, are drying up earlier in the year, leaving both farms and communities without essential water. Prolonged droughts have become more frequent, and water rationing has already begun in several districts. This leads to more animals attempting to enter farming areas in search of water and meeting untimely deaths in large unprotected wells that have been dug for farming water supplies.

• Forest fires: Previously rare, forest fires are becoming more common in highland and dry zone forests. The 2023 Horton Plains fire scorched over 100 hectares of fragile montane forest, setting back years of conservation work. Firefighters and environmentalists warn that such events are likely to increase.

• Human-animal conflict escalation: The scarcity of water sources will lead to higher levels of conflict that may lead to the loss of wildlife and human life.

Adaptation in action: Can SL beat the heat?

Though the challenges are steep, Sri Lanka is not without options.

Addressing the heat crisis requires a multifaceted approach:

• Green infrastructure and cooling design: Urban planners in Colombo are now experimenting with green roofs, urban forests, and reflective building materials to combat the urban heat islands effect. Drawing inspiration from Singapore, cities are exploring how trees and strategic airflow can lower surface temperatures by up to 2°C. The better utilisation of resources in cities is needed to ensure that there is less heat trapped during rush hours for schools and workplaces.

• Education and public engagement: Educating the populace on heat-related risks and preventive measures is crucial for community resilience. Nationwide campaigns have begun promoting hydration-related awareness, heat safety protocols, and the importance of tree planting in schools and public spaces.

• Policy and global engagement: Formulating and enforcing policies aimed at reducing greenhouse gas emissions and promoting sustainable practices are essential for long-term mitigation. This, in addition to engaging with global treaties as well as support for heat mitigation, is crucial in supporting the country’s ageing infrastructure including renewable energy investment, forest protection, and sustainable transport initiatives. But, international support will be key – both in finance and technology.

• Protecting our freshwater sources: Ensuring that development plans do not divert essential water from areas that require the same to replenish groundwater and our water cycle.

• Innovation and re-purposing of traditional methods: The importance of harnessing renewable energy as well ensuring the utilisation of less fossil fuel-based energy production is vital as heat is a by-product (European Geothermal Energy Council, this year. Innovations including repurposing locally sourced materials for buildings as well as traditional cooling pots for produce and water made of clay keep water cool without the need for energy-based cooling. Innovations such as the HeatRisk Tool by the United States National Weather Service developed in 2014 may be localised and adopted in local contexts to support communities to gain advanced heat warnings as well as to gain preparatory support during heatwaves. Indian households utilise clay materials as building components for cooling while the TERI School of Advanced Studies University stands as an incredible feat of engineering which cools during the summer and warms during the winter in India.

Looking ahead: A race against time

Without substantial mitigation, scientists warn that Sri Lanka will likely experience extreme heat waves exceeding 40°C in the next two decades. This would be immensely catastrophic for the way of life for everyone, across the forest to the farm. The country stands as a case study of how even small island nations can face disruptive and disproportionate impacts from a global problem. This scenario underscores the vital urgency for comprehensive climate action at both the national and global levels.

Conclusion: A nation at heated crossroads

Sri Lanka's escalating heat crisis is a grim reminder of the severe impacts of climate change. The heat crisis is no longer a distant threat – it is a lived reality. It is not merely a meteorological anomaly but a full-spectrum emergency touching every aspect of life: from classrooms to hospitals, forests to farmlands. The convergence of climate change, natural climate cycles, and urban expansion has made the island a furnace in flux.

Yet there remains hope. Through smart planning, resilient infrastructure, informed policy, and international solidarity, Sri Lanka can forge a pathway out of the heat. But, the window is closing – and the temperature is still rising.

(The writer is a climate specialist with a background in environmental management)

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The views and opinions expressed in this article are those of the author, and do not necessarily reflect those of this publication