Why Model the Earth System?

Why Model the Earth System?

Satellite imagery of the great flood of the Mississippi River, 1993 in the area around St. Louis, MO comparing August 1991 and 1993.

Why do we model the climate system?

Since the start of the Industrial Revolution, greenhouse gases, principally carbon dioxide, have increased substantially in the atmosphere. The past several decades have seen a significant rise in global surface temperatures. The climate change associated with this warming may have profound impacts for society. For example, the frequency of extreme events, like the flooding that struck the midwest in 1993, may increase with a high toll on society.

Observed Surface Winds, Ocean Temperatures, and Currents across the Equatorial Pacific, Oct 2006 to Sep 2011

Understanding how climate changes in response to changes in the composition of the atmosphere and other factors drives climate research. Climate models provide a tool to understand how processes work and interact with each other. For example, El Nino/Southern Oscillation (ENSO) is a mode of climate variability that strongly influences weather in North America and beyond. It results from a complex interaction of atmosphere and ocean. This animation shows observed winds, ocean temperatures, and currents across the Equatorial Pacific through five years of an ENSO cycle. Successfully modeling the complex interactions that result in ENSO allows researchers to understand the roles of the processes involved and how they interact.

Photo of the Shasta Dam

We also use models as a tool to look into the future, just as we use weather forecast models to make predictions. Both weather and climate models provide information for societal needs. For example, planning for future water and hydrologic needs requires looking far into the future. Building a dam, like the Shasta Dam shown here, requires a long lead time.