In 2006 the ENIGMA (Earth System Network of Integrated Modelling and Assessment) network was founded. ENIGMA is a joint Initiative of MPI-BGC (Jena), MPI-C (Mainz), MPI-M (Hamburg), and PIK (Potsdam) to support communication, cooperation and common developments in the field of Earth System Sciences. Several major work packages were setup within ENIGMA:

• Land Use, Biosphere and the Earth system
  
• Climate modules for economic optimisation
  
• Aerosols and the water cycle
  
• Methane changes since pre-industrial
  
• Nitrogen-Carbon cycle
  
• Millennium simulation
  
• Holocene carbon dioxide
  
• Glacial cycles

Coordinator: Jochem Marotzke