Integrated Biosphere Simulator (IBIS)

What is IBIS?

IBIS stands for the Integrated Biosphere Simulator, and it is a computer model used to model the Earth’s biosphere. It was created by the Center for Sustainability and the Global Environment (SAGE) at the University of Wisconsin-Madison.

Download the IBIS model code

How Does it Work?

The model runs on a grid, usually half of a degree square, where each gridcell is said to have the average qualities of the land that it contains. For example, the gridcell’s elevation would be the average elevation of the land contained by the boundaries of the gridcell.

Based upon all of these average characteristics the model uses a series of equations based on climatic information (such as temperature, precipitation, and cloud cover), the type of vegetation present, as well as other variables (such as soil properties) to calculate the characteristics of the gridcell. Not only does the model take into account the many inputs and outputs of the Earth system, it also handles the multiple timesteps involved, running on hourly, daily, monthly, and yearly timesteps simultaneously.

The Technology

In the past, to deal with the massive amount of information required, models like IBIS had to be run on large supercomputers which would often run for a month or more before returning results. With recent the technological advancements made in computer science, these models are more accessible than ever. On a mid-range personal computer today, IBIS can run a global 10-year simulation in only a few days.

Modeling for the Future

Models like IBIS are increasingly being used by scientists interested in what the future holds for the Earth’s climate. Many predictions about future climate change revolve around increased levels of Carbon Dioxide and greenhouse warming. Through the use of these computer models, scientists can determine to what degree these predictions hold true.