Blog: Compound climate events are on the rise – it’s time for action

by Roop Singh, Carolina Pereira Marghidan, Luciana Escobar and Cale Johnstone

(This article appeared first last week on the website of the Zurich Climate Resilience Alliance, an IFRC partner organization; it has been edited here for length. The full paper of which it’s a synopsis – Double jeopardy: addressing compound flood and heatwave events – is available from the Global Disaster Preparedness Center.)

Compound events – where two or more hazards such as heatwaves and floods occur simultaneously or in close succession – are becoming more common. This often results in more severe negative outcomes than if each hazard were to occur separately.

Recent events in Pakistan and the US highlight existing resilience gaps and the adaptation solutions required to reduce the impact of compound events.

As climate change intensifies the frequency and severity of extreme-weather events, the phenomenon of compound events has become increasingly critical to understand and address. 

Urbanization exacerbates risks through the urban heat-island effect, impervious surfaces, and inadequate drainage systems, increasing exposure and vulnerability. 

In 2022, Pakistan faced a record-breaking heatwave that was soon followed by unprecedented monsoon rains. The extreme heat had dried out the soil, reducing its ability to absorb water and exacerbating flooding that displaced 33 million people and inundated a third of the country.

Urban areas like Karachi (photo) struggled with housing shortages and disease outbreaks as displaced populations sought refuge. The economic impact was staggering, exceeding US$ 30 billion, pushing millions into poverty. 

‘These examples highlight the urgent need for resilient infrastructure, including drainage and power systems, capable of withstanding compound events’

In July 2024, Hurricane Beryl struck Texas resulting in extensive flooding and widespread power outages. As recovery efforts commenced, a severe heatwave followed, with temperatures almost reaching 38°C.

The lack of electricity meant that cooling centres were unavailable, leaving residents vulnerable to dangerous heat-related conditions. Hospitals quickly became overwhelmed with patients suffering from heat stress and carbon monoxide poisoning due to unsafe use of generators. 

Both of these examples highlight the urgent need for resilient infrastructure, including drainage and power systems, capable of withstanding compound events. More must also be done to assess the risk of multi-hazard events and respond accordingly.

By combining multi-hazard approaches, nature-based approaches, smart urban design, and community-led initiatives, cities can create safer, more sustainable environments. Investments in these solutions not only tackle immediate climate hazards but also foster long-term resilience against the growing threat of compound events.

Multi-hazard approaches to risk assessment, planning and preparedness – for example, through back-up power systems, multi-purpose cooling and evacuation centres – ensure adaptation strategies are built to address the interconnected nature of climate risks.

Nature-based solutions offer a powerful approach to managing the impacts of both heatwaves and floods, while delivering broader ecological benefits. Urban green spaces play a crucial role in cooling cities through shade and evapotranspiration, while also improving water absorption to mitigate flood risks.

Climate-smart urban planning is essential for addressing compounding climate events. Strategies that incorporate smart design, such as permeable pavements, elevated structures, building designs and materials that improve ventilation and rooftop rainwater harvesting systems, can significantly enhance resilience.

Communities are at the forefront of adapting to compound events, and empowering residents through education and engagement is vital to ensure adaptation efforts are tailored to local needs.

Red Crescent volunteers help families affected by the 2022 monsoon floods pitch tents near Karachi. The IFRC launched an emergency appeal for 26.5 million Swiss francs, kick-started with an IFRC-DREF allocation of nearly half a million CHF, to assist more than 300,000 people in August that year. (Photo: Turkish Red Crescent visa IFRC Asia Pacific)