Climate–water interactions—Challenges for improved representation in integrated assessment models

Water plays a major role in the climate system and in mediating impacts of climate variability and change on all sectors of the economy. The incorporation of water resources modeling into integrated assessment models (IAMs) to study climate–hydrology processes, related water impacts and adaptation options is thus an area of interest, yet it poses a number of methodological challenges. In particular, models of economic activity, climate, water availability and use, and adaptation are developed at differing temporal and spatial scales and with different goals. This makes their integration highly complex and computationally demanding. In this review we highlight a set of modeling challenges in water resource systems, describe the state of the art of approaches to integrating water resources modeling with IAMs and economic modeling, and identify constraints and opportunities moving forward in the development of water resources modeling within the IAM frameworks.