Building Earth system models to predict the American West climate

A helicopter fighting a forest fire with smoke in the background — *National Interagency Fire Center*

Lecture

Nov. 4, 2026

6:30 – 7:30 pm MST

Prost Wheat Ridge Biergarten, 3801 Crossing Dr Wheat Ridge, CO 80401

How and why are precipitation, temperature, and wildfire risk changing in the American West, and what does the future hold? These are critical questions that communities are grappling with across the region.

In collaboration with the Western Denver Trout Unlimited Chapter, NSF NCAR’s Isla Simpson will take us behind the scenes of Earth system models, discuss the building blocks that make up these powerful tools, and how they are used to both understand historical change and make future predictions. Drawing on examples from the American West, she will highlight what uncertainties remain and how scientists are working to improve predictions of the future.

Isla Simpson

CGD, NSF NCAR

I am a scientist in NSF NCAR’s CGD laboratory, where my research interests lie in Earth System Modeling and in the use of these models to understand and predict Earth system variability at spatial scales ranging from the planetary to the regional, and on timescales from seasonal to multi-decadal. I seek to determine robust responses to external forcings and their implications through a deeper understanding of the processes and mechanisms involved and to understand the origins of Earth system variability in the historical record. I am also interested in the biases that occur in Earth System Models and how they may be alleviated and what the implications of these biases are for our ability to predict Earth System variability. To date, I have focussed on the dynamics of the tropospheric mid-latitude circulation, the water cycle, the coupled stratosphere-troposphere system, land-atmosphere coupling, historical trends in the observational record and their representation in models, the use of emergent constraints, and seasonal to decadal prediction.