The Climate Modeling Process

From development to validation - how scientists build trustworthy climate models

Building and Testing Climate Models

1

Model Development

Scientists code physics equations into computer programs, representing atmosphere, ocean, land, and ice processes. Teams of climate scientists, mathematicians, and computer programmers work together over years to develop and refine each model.

Code Components

  • • Millions of lines of code
  • • Fortran, C++, Python
  • • Parallel computing architecture

Computing Power

  • • Supercomputers required
  • • Months of computation time
  • • Petabytes of output data
2

Model Validation

Before trusting future projections, models must accurately reproduce past climate. Scientists compare model outputs against historical observations - temperature records, ice core data, satellite measurements, and paleoclimate evidence.

Interactive: Model vs. Observations

Observed
0.85
Model Projection
0.82
°C increase since 1900Accuracy: 96%

Models are validated against historical observations. Good agreement with past climate gives confidence in future projections.

3

Ensemble Modeling

No single model is perfect. Scientists run multiple models (ensembles) and multiple scenarios to understand the range of possible futures. The IPCC assesses results from 30+ modeling centers worldwide, each with different approaches and assumptions.

Why Multiple Models?

  • • Different physics implementations
  • • Varying grid resolutions
  • • Different parameterization schemes
  • • Agreement across models = higher confidence

⚠️Understanding Uncertainty

Climate projections always include uncertainty from three sources:

Scenario Uncertainty
We don't know future emissions
Model Uncertainty
Imperfect representations
Natural Variability
Chaotic climate fluctuations