The Environmental Policy Integrated Model (EPIC)
At IIASA, EPIC is used to compare land and forest management systems and their effects on environmental indicators like water availability, nitrogen and phosphorous levels in soil, and greenhouse gas emissions.
EPIC can analyze several crop types and their management under different weather, topographical, and soil conditions. It investigates the trade-offs between plant growth and yield on the one hand, and environmental impacts and sustainability on the other.
For example, EPIC can estimate—based on soil type and prevailing climatic conditions—the extent to which nutrients from fertilizer, such as Nitrogen (N) are leaching into nearby river and stream networks. This problem is of growing concern as globally, two-fifths of N used in agriculture is lost to ecosystems, with harmful environmental effects.
FAST FACTS
- EPIC simulates agricultural activities and their interactions within ecosystems on a daily basis.
- EPIC is widely used by scientists around the world. Research groups, like IIASA, can calibrate the model to meet their own analytical needs.
- EPIC has accurately simulated agricultural conditions and practices for hundreds of years into the past. This makes it an excellent basis for projecting future trends in global change.
Nitrous oxides (NOx) emissions are also produced when N from fertilizer is broken down by microbes in water. NOx are now estimated to represent 6% of all greenhouse gas (GHG) emissions.
How the model works
EPIC, as used at IIASA, models a wide range of biophysical processes to consider alternative land uses where land is becoming degraded or is putting natural ecosystems at risk.
It includes a full water cycle, allowing researchers to analyze how water is moving on, above, and below the Earth's surface. It can simulate different weather patterns and events, such as the effects on forest or crop production of heavy rainfall or prolonged drought, and it can estimate plant growth and yield based on the temperature or moisture content of the soil. The effects on crop productivity of natural processes, such as erosion and sedimentation, and of human activities, such as soil tillage, can also be fully demonstrated. The impacts of land use on carbon cycling, GHG emissions and soil functioning will be the main modeling focus for EPIC in the foreseeable future.
Model applications
At IIASA, EPIC is part of the toolkit used to assess the economic and environmental effects on agricultural and forest lands of enhancing carbon sinks and GHG abatement measures.
EPIC plays a central role in IIASA’s current projects including LC-IMPACT, Carbo-Extreme, ISAC and FarmSupport.
About the EPIC model
The EPIC model was developed by the United States Department of Agriculture to assess the status of U.S. soil and water resources and has been continuously expanded and refined to better analyze the exchange of GHG fluxes between terrestrial ecosystems and the atmosphere. It is used around the world by research groups, like IIASA, who calibrate EPIC to meet their own needs.
Verifying and updating the model
EPIC is integrated into the major models EUFASOM and GLOBIOM, set up by IIASA's partner, the University of Natural Resources and Life Sciences (BOKU) of Vienna, and is now operational.
The future focus of the model at IIASA will be analysis of GHG emissions and carbon sequestration in the agricultural sector. EPIC already includes tools to analyze carbon and nitrogen in the soil, and a methane analysis module is under preparation. Links to IIASA's GAINS model are being strengthened.