Hurricanes. Wildfires. Droughts. Floods. All of these threaten livelihoods and development. And with extreme weather phenomena only increasing due to rising global temperatures caused by human-induced climate change, it’s often the poorest communities around the world that suffer the most from the consequences.

Infrastructure is often used to mitigate the impacts of extreme weather events – building dams, for example, to prevent flooding from heavy rains, or storing water for dry periods – but often at huge costs. In order to address these and other risks, we need to find financially feasible, innovative solutions that don’t use a ‘business as usual’ approach. We can’t simply continue implementing infrastructure projects as we’ve always done.

Let’s take water.

Regardless of where you are in the world and what you do, water is essential to survive and thrive. From clean water to drink and cook with, to water for sanitation, agriculture and manufacturing, water is a vital resource. But in many of the countries in which UNOPS works, communities often face two extremes: Floods and droughts – too much water and not enough. In addition to the obvious threat to communities' ability to develop and prosper, people within communities affected by floods and droughts also face long-term health risks.

The traditional approach to preventing floods and droughts is to build grey infrastructure with concrete and stone, such as reservoirs, drainage canals and flood protection walls. But in terms of flood risks, grey infrastructure can actually make things worse – for example, their impervious surfaces don’t allow water to be absorbed by the soil underneath.

Nature-based green infrastructure can help mitigate risks related to water availability – and at a much lower cost.

Green infrastructure uses a combination of natural structures that can produce a positive environmental, social and economic impact. The approach can help to prevent flooding and droughts, as well as create greater biodiversity, improve air quality and save energy, among other benefits.

Combining green with traditional grey infrastructure can therefore lead to more cost-effective, efficient and flexible solutions that are vital for long-term sustainable development.

This approach has been an important focus within several projects I have worked on with UNOPS. Here we have merged traditional grey infrastructure with green infrastructure components to create a much greater impact – and usually at lower cost.

In Sri Lanka, ponds and water reservoirs are essential for water retention and groundwater recharge, especially in the north, where surface waters are extremely rare and the population relies on groundwater for drinking and agriculture. Unplanned urban development often results in pond systems being filled in and destroyed, threatening this important resource.

Working with local authorities to improve the network of drainage canals in Mannar and Vavuniya, UNOPS conducted flood mapping and hydrological studies in order to establish the most effective drainage networks, demarcated pond boundaries and restored ponds in the townships. Preserving natural ponds to act as water storage and help with flood mitigation provided an almost cost free solution, as they are naturally located at the lowest water level.

The past few rainy seasons in Sri Lanka have already demonstrated the positive impact of working with nature: Flood waters filled the ponds in Mannar instead of the gardens and homes of community members.

The benefits of using green infrastructure alongside more traditional grey infrastructure are clear: Increased resilience and an infrastructure product that works with its surrounding environment. This innovative approach helps support long-term development, as well as social, economic and environmental sustainability.

We should insist on this green approach for all infrastructure projects, big and small.