Assessments of water resources and their management

5. What is the specific impact of climate change on water resources?

Climate change expresses itself through water as 9 out of 10 natural disasters are water-related. Water-related climate risks cascade through food, energy, urban and environmental systems. To achieve climate adaptation and development goals, water must be at the core of adaptation strategies.

Climate change will indeed worsen the situation by altering hydrological cycles, making water more unpredictable and increasing the frequency and intensity of floods and droughts. The roughly 1 billion people living in monsoonal basins and the 500 million people living in deltas are especially vulnerable. Flood damages only from property damage are estimated in $120 billion per year and droughts pose, among others, further constraints to the rural poor, highly dependent on rainfall variability for subsistence.

To guide effective climate change adaptation, activities should reflect the importance of water management for reducing vulnerability and building climate resilience, prioritizing the following actions:

• (i) Expand beyond traditional integrated water resources management (IWRM). Efforts to reduce greenhouse gas emissions also depend on access to reliable water resources, as all mitigation actions need water to succeed.
• (ii) Promote investment and solutions that incorporate management of ‘natural infrastructure’ – the ecosystem services provided by healthy watersheds and coasts – and their benefits for climate-resilient development of the food and energy sectors.
• (iii) Support actions at scale to build climate resilience by combining watershed management, sustainable infrastructure, and empowerment and learning through adaptive institutions.