C-ROADS is an award-winning computer simulation that helps people understand the long-term climate impacts of policy scenarios to reduce greenhouse gas emissions. It allows for the rapid summation of national greenhouse gas reduction pledges in order to show the long-term impact on our climate.


  • Translates climate mitigation scenarios into emissions, concentrations, temperature, and per-capita emissions outcomes
  • Offers ability to quickly run real-time policy analysis on a laptop or desktop computer
  • A graphical user interface that non-modelers can use to test “what if scenarios”
  • Ability to analyze up to 15 different nations or negotiating blocs simultaneously.
  • Backed by a scientific review committee of renowned climate and systems dynamics experts
  • Outputs are consistent with the larger, more disaggregated models used in the IPCC’s AR4
  • Model assumptions, inputs, and methodology are made transparent and in many cases can be easily adjusted to suit the user
  • Video tutorials are available online to guide use

Sterman at COP15
 MIT’s John Sterman of the Climate Interactive team explains C-ROADS science and confidence building at a US State Department side event in Copenhagen.

Role of C-ROADS

Building on the Kyoto Protocol and outcomes from the UN climate negotiations, individual nations are making proposals and pledges to reduce greenhouse gas emissions. These proposals take different forms, with different reference years, reference scenarios, target years, and types of proposals. Determining whether or not these proposals together are enough to achieve climate stabilization is possible with complex disaggregated climate simulations, however, such models can be slow to run and inaccessible to non-modelers.

To address this we have developed C-ROADS to provide an easy to use tool whose results give users a rapid overview of the long-term impacts of proposals. We’ve designed and tested C-ROADS to provide negotiators and other decision-makers around the world a common platform to support their discussions. C-ROADS allows pledges to be quickly aggregated into a global emissions trajectory. From that emissions trajectory, C-ROADS calculates future greenhouse gas concentration, temperature, and sea level rise. The goal is to complement, not supplant, the larger disaggregated models such as MAGICC, MINICAM, AIM, and others.  Indeed, output from C-ROADS can be saved as .xls or .gas files to be further tested in other models.


Pangea Stacked GraphC-ROADS was developed by a team from Climate Interactive, Ventana Systems, UML Climate Change Initiative, and MIT. The name “C-ROADS” stands for “Climate Rapid Overview and Decision Support” simulator. C-ROADS is easily used by non-modelers, and runs in less than 0.1 second on a laptop computer. It has undergone a scientific review from an independent team of respected climate scientists, climate modelers, and system dynamicists. The scientific review committee, chaired by Dr. Robert Watson, former Chair of the Intergovernmental Panel on Climate Change, recommend C-ROADS for widespread use. Read a summary of their review here. In 2013 C-ROADS was awarded the System Dynamics Society Award for the best “Real World” Application of System Dynamics.

C-ROADS is being used at top government, corporate, and NGO levels, and by individuals participating in or monitoring the UNFCCC negotiations. Read comments by some of our users at the US State Department and European Environment Agency.

Trevor HouserTrevor Houser of the US State Department discusses his experiences as a C-ROADS-CP user.

C-ROADS operates at two levels of regional disaggregation — 6 or 15 global negotiating blocs. This allows users to ask questions such as: what if all countries follow their current commitments? what if the EU reduces emissions 80% below 1990 by 2050, Mexico drops 50% below 2002 by 2050, China continues decreasing its emissions intensity, and so on?

The origins of C-ROADS is the 1997 PhD dissertation of Dr. Thomas Fiddaman, “Feedback Complexity in Integrated Climate-Economy Models,” MIT Sloan School of Management. Dr. Fiddaman now works with Ventana Systems, one of the creators of the current version of C-ROADS as well as other economy-energy-environment simulations. In addition to C-ROADS we have developed several simulations that use the same scientifically reviewed model behind C-ROADS but are in forms that are oriented towards education or focus on particular results that C-ROADS gives us.

  • C-Learn, a learning-oriented, three-region version of this simulator, is available online for anyone to use, adapt, extend, and translate into new languages.
  • Climate Momentum Simulation is designed to quickly show the dramatic effects that changing CO2 emissions can have on our planet.
  • Climate Pathways is an app for iPhones, iPads, and iPods that allows users to guess the emissions trajectories needed to limit global warming to 2 degree or less.
  • World Climate is a role-playing game designed for groups of all sizes to experience the dynamics that negotiators face at the UN climate negotiations in coming up with a global climate treaty.
CO2 Graph from Pangaea

C-ROADS Resources:


Click here to view a larger version of the video

C-ROADS is copyright 2013, Climate Interactive and Ventana Systems.