World-Earth Models

What is World-Earth Modeling (WEM)?

World-Earth Models (WEMs) connect human decisions with Earth system feedbacks. Unlike traditional Earth System Models (ESMs), they model society and nature as co-evolving systems rather than treating humans as external drivers.

The key difference: Traditional ESMs use fixed scenarios for human behavior, while WEMs simulate how human decisions actually change in response to environmental feedback - and how those changes then affect the environment again.

How WEMs Work

Unlike ESMs, WEMs feature:

  • 🔄 Bidirectional coupling: Human decisions affect the environment, environmental changes influence human decisions
  • 👥 Dynamic human agency: People adapt their behavior based on what they observe and learn
  • 📊 Closed feedback loops: Environmental changes immediately influence future human behavior
  • 🌍 Global scale: Simulates these dynamics across the entire planet simultaneously

This creates coevolutionary dynamics where human societies and Earth system processes shape each other over time - something impossible with traditional modeling approaches.

The copan:LPJmL Framework

copan:LPJmL is the first practical framework for building WEMs by combining detailed land system modeling (LPJmL) with flexible social modeling (copan:CORE).

Technical innovations that enable WEM development:

  • 🔗 Annual coupling: LPJmL and social processes exchange data every simulation year
  • 📊 Three taxon structure: ENV (biophysical), MET (socio-metabolic), CUL (socio-cultural) processes
  • 🌍 Global grid integration: Social agents operate on the same 0.5° × 0.5° grid as LPJmL (67,420 cells)
  • ⚡ Modular design: Supports agent-based, rule-based, optimization, and AI-enhanced approaches

See our examples for three working WEM implementations that demonstrate these capabilities in practice.

Ready to Explore?

📚 Examples - See WEMs in action
🔧 Documentation - Technical details
🤝 Community - Join researchers

The first framework to truly connect human decisions with Earth system feedbacks - enabling breakthrough research into coevolutionary dynamics.