Integrated Assessment Research

The goal of the Integrated Assessment Research (IAR) program is to advance scientific understanding of the complex interactions, interdependencies, and co-evolutionary pathways of human and natural systems, including interdependencies among sectors and infrastructures. There is a particular emphasis on understanding the energy-water-land nexus under both realistic and idealized forcing scenarios, including the evaluation of scale-aware processes and probabilistic uncertainties that can lead to instability through thresholds and tipping points. The program additionally considers the role of socio-economics, risk analysis, and complex decision theory, as they pertain to describing the evolution and feedbacks within earth system science.        

Program Description

IAR Workshop Report
Latest IAR sponsored workshop report, centered on an interagency activity involving multi-disciplinary science community input, addresses: Understanding Dynamics and Resilience in Complex Interdependent Systems – Prospects for a Multi-Model Framework and Community of Practice.

The human-Earth system, including settlements, infrastructure, natural resources, socio-economics, and importantly, interdependent sectors and natural systems, is highly complex and continuously changing.   Both strong and weak linkages define the oftentimes non-linear behaviors among components. Stressors, constraints, and other factors affecting change can take many forms and influence the system at varying spatial and temporal scales, oftentimes in unanticipated ways when viewed within the larger system. Consider, for example, the individual and combined effects of changing patterns of weather and its extremes, demographic distributions, economic growth and changes in industrial structure, improvements in technologies (e.g., for producing electricity), depletion of natural resources such as groundwater, or the discovery of new resources or means for resource extraction such as unconventional natural gas, and the evolution of regulatory and other institutional structures. All of these factors influence infrastructures and sectors that in turn can exhibit nonlinear regional responses as part of the earth system.   

One major focus of the IAR program is in understanding the growing interdependencies and risks at the intersection of the energy, water and land sectors. The recent disruptive effects and economic losses associated with the growing intensity, frequency, and persistence of droughts, floods, heat waves, and tropical storms in the United States have highlighted the importance of this research and integrated modeling capability. For example, energy is required for water and wastewater treatment, groundwater pumping, and large-scale inter-basin transfers. Needs, risks, and vulnerabilities of the coupled system are large and growing in the face of shifting weather and precipitation patterns, water supplies that depend on increasingly limited groundwater, transitions in regional economic development (including land use), as well as U.S. population shifts. In contrast, approximately 45% of water withdrawals in America’s rivers and streams are for energy applications, ranging from thermo-electric cooling (e.g., fossil and nuclear power plants) to domestic oil and gas recovery. Hydropower is similarly challenged to respond to increasing competition for limited water supply.

Besides the program focus to understand the system dynamics governing interdependencies within the natural-human system, the program seeks to advance our understanding of system nonlinearity and instability associated with multiple stressors that can lead to cascading failures in connected sectors and systems. An important characteristic of nonlinearity and system failure is the probabilistic interdependence near thresholds associated with extreme weather, severe drought, and infrastructure vulnerability. Consequently, the program supports the development of interoperable tools and methods for integration with agile, flexible earth system modeling frameworks, revealing a basic understanding of different levels of complexity required to analyze interdependency. 

Program Funding Opportunity Announcements

Announcements are posted on the DOE Office of Science Grants and Contracts Website and at Information about preparing and submitting applications, as well as the DOE Office of Science merit review process, is available at the DOE Office of Science Grants and Contracts Website. For current announcements visit BER Funding Opportunities.

The most recently closed Announcement (DE-FOA-0000219) requested applications for a single, coordinated research effort that would: 1) advance progress on a select set of major scientific challenges in the field of Integrated Assessment that are widely recognized and confronting the major Integrated Assessment modeling teams, 2) advance methods and capabilities for inter-model testing and diagnostics, and 3) enhance capabilities for multi-model, "ensemble-like" analyses for improved insights in science studies and science-based analyses.

Why the Program's Research is Important

IAR is necessary to understand the nonlinear science involving natural-human interdependency and feedbacks on the earth system. The program helps shape our fundamental understanding of complex stressors on human systems and infrastructure, vulnerabilities and risks at the energy-water-land nexus, multi-sector dynamics, and more generally, implications for regional and global economic development in the face of changing weather patterns and extremes, advances in technology, availability of natural resources, and feedbacks to natural systems, including regional and global climates.  

Featured Reports

Recent Content

Recent Highlights

Model validation is an important scientific activity. In a model validation method called hindcasting, a model is run over a historical time period, testing its ability to reproduce the observed past. This paper reports the results of a hindcast experiment using the Global Change Assessment Model’s...
Modeling agriculture within the Earth system is important not only to predict crop yields and assess food security but also to better understand the intertwined and complex processes in the climate-water-land nexus. Among other factors, efficiently using improved fertilizing techniques by...
This study uses innovative methods to understand how urban form impacts urban energy use and the quality of life for urban residents. The research provides a global-scale analysis of future urban densities and associated energy use in the built environment under different urbanization scenarios.
Droughts reduce hydropower generation and generation capacity of thermoelectric plants due to constrained cooling.  Critical droughts require electricity grid operations to deviate from normal to avoid unserved energy in the summer. The research estimates electricity grid operations over the...
Storm surge simulations are sensitive to tropical cyclone winds, so it is important to evaluate how well the latter can be simulated using dynamical models.


We report results of a “hindcast” experiment focusing on the agricultural and land-use component of the Global Change Assessment Model (GCAM). We initialize GCAM to reproduce observed agriculture and land use in 1990 and forecast agriculture and land use patterns on one-year time steps to 2010. We...
In this study, we applied version 4.5 of the Community Land Model (CLM) at a 0.125° resolution to provide the first county-scale model validation for simulating crop yields over the Conterminous United States (CONUS). Large bias was found in simulating crop yields against U.S. Department of...
Although the scale of impending urbanization is well-acknowledged, we have a limited understanding of how urban forms will change and what their impact will be on building energy use. Using both top-down and bottom-up approaches and scenarios, we examine building energy use for heating and cooling...
In a workshop on April 20 and 21, 2016, USGCRP's SISCG brought together 20 experts from the federal government, the national laboratories, and academia to tackle the overarching science question:  How might the economic character of the United States evolve at time scales ranging from annual to...
Large-scale assessments of the vulnerability of electric infrastructure are usually performed for a baseline water year or a specific period of drought. This approach does not provide insights into the full distribution of stress on the grid across the diversity of historic climate events. In this...