The session will focus on how regional cooperation can help countries to plan for effective climate mitigation and adaptation strategies, and a more efficient use of natural resources such as water, land, and energy in a changing climate. Different resource base between countries generates potential complementarities, which can be seen as synergies that can be realized through integrated and transboundary water cooperation and regional trade of food and energy. These interlinkages need to be taken within the context of ecosystems, their carrying capacities and the critical functions they provide for our stability, security, lives and livelihoods. The session will be an occasion to reflect on the role of the water-energy-food- ecosystems nexus and transboundary and regional cooperation in relation to the NDCs, drawing from the experience of countries.