WEAP for adaptation planning water and climate resilience

As climate change impacts escalate around the world, adaptation is more urgent than ever. The latest round of nationally determined contributions (NDCs) under the Paris Agreement reflects this, with 73% of submissions as of 30 September 2025 including adaptation goals, according to the UNFCCC in October 2025. Sixty-seven countries have already submitted national adaptation plans (NAPs), and 77 more are developing them. Water is at the core of many countries’ adaptation priorities, as climate change deepens water stress in arid areas; makes rainfall less reliable and more extreme, with both dry spells and floods; and degrades water supplies in multiple ways, including through saline intrusion due to sea-level rise, according to the Working Group II contribution to the IPCC’s Sixth Assessment Report. Water is also central to achieving the Global Goal on Adaptation and most targets in the UAE Framework for Global Climate Resilience – not just the first, on reducing water scarcity, enhancing resilience to water-related hazards, and building a climateresilient water supply, but also targets on agriculture and food security, human health, ecosystems and biodiversity, and infrastructure.

The Water Evaluation and Adaptation Planning (WEAP) platform can be a vital tool for decision-makers and stakeholders to understand climate impacts on water systems, explore adaptation options, and measure progress towards adaptation targets, with detailed data on key indicators. With a 35-year track record and more than 50 000 users in 190 countries, WEAP is a scenario-based modelling tool that integrates both supply- and demand-side perspectives. Users can analyse how different climate change
scenarios might affect water availability; how different resource allocation choices might affect the economy, human well-being and ecosystem health; and the relative benefits of efficiency measures, added storage, flood protection and other potential interventions.

Water experts at SEI not only maintain and continuously improve WEAP, but have also applied it widely, building capacities and creating highly participatory processes that have enabled stakeholders worldwide to co-create sustainable and inclusive adaptation solutions. WEAP models typically cover entire watersheds and have supported water resources and adaptation planning in transboundary river basins, at the national and watershed level, and at the local level. This means WEAP can support both top-down and locally led adaptation initiatives. Macroeconomic modelling capabilities and integration with SEI’s Low Emissions Analysis Platform (LEAP), a widely used energy and climate mitigation planning tool, can provide a wealth of additional insights (LEAP & WEAP, 2025).

source :

https://www.sei.org/wp-content/uploads/2025/11/weap-adaptation-planning-water-climate-resilience.pdf