The concluding session at Earthna Summit 2025 on Wednesday highlighted the power of blending time-tested knowledge with cutting-edge technology in providing solutions for urban centres facing increasing environmental challenges.Speaking on 'The Case for an Arid Cities Network', Msheireb Properties CEO engineer Ali al-Kuwari cited the long-term benefits of investing a project like Msheireb Downtown Doha (MDD).“Our district cooling system is a good revenue source for us. Today, we are almost 80% (occupancy), and once it becomes 100%, we’ll be getting good revenue from it, and it is very efficient,” he said, noting the project’s success in combining modern innovation and traditional knowledge.Beyond the economic advantages, al-Kuwari also stressed the environmental benefits of their approach, saying that MDD collects and reuses rainwater and condensation from air conditioners for irrigation and toilet flushing. This, he pointed out, resulted in a 70% reduction in water consumption.Drawing lessons from traditional architectural urbanism, al-Kuwari explained that they redesigned the entire downtown area based on local traditions and building practices.“We looked at our traditions, our people how they used to build their own houses, their homes, their village,” he said. This included keeping buildings close together to maximise shade and capture breezes, reducing heat by 30%.Al-Kuwari noted that these techniques have been in operation for five years, with collected data demonstrating the replicability of the concept in other cities.Ibrahim Thiaw, undersecretary general and executive secretary of the United Nations Convention to Combat Desertification, underscored the significance of considering solutions applicable even without high-tech infrastructure. He pointed to the building materials and techniques used by his ancestors in drylands, which provided comfort without air conditioning.Thiaw also cited ancient underground irrigation systems as examples of indigenous knowledge that are being revived for their efficiency.“If you look at the aridity climates, it is very clear, according to scientific studies, there will be more aridity in the world, it is growing. It is growing in places where the population is also growing because demographics continue to grow.Thiaw noted that of the nearly 600 cities, a few hundreds more are expected to emerge (as arid) over the next 50 years, especially those in developing countries, many of which may lack access to reliable energy.