June 1, 2023 by Climate Interactive
The June 2023 update to the C-ROADS Climate Change Policy Simulator introduces major improvements and additions; including a new Baseline Scenario that incorporates the economic impact of climate change; and model improvements to land, forests, and agriculture.
Read further or watch the video above for more details.
The C-ROADS Baseline Scenario now results in a temperature increase by 2100 of 3.3°C rather than 3.6°C. Most of the change in the Baseline temperature is due to the addition of an economic damage function. A damage function is a feedback mechanism where temperature increase causes lower economic growth due to climate impacts such as storms, sea level rise, and droughts, which results in lower energy demand and thus lower CO2 emissions. The C-ROADS baseline, like En-ROADS, uses a study by Burke et al. (2018)1 because it falls in the mid-range of similar peer-reviewed studies.
The damage function can be switched off from the Current Scenario by navigating to Simulation > Assumptions > Growth and toggling the switch “Climate change slows economic growth.”
The June 2023 update improves the modeling of different types of land (e.g., forests and farmland), the conversion of land from one type to another, and the carbon cycle impacts. C-ROADS now better captures the dynamics of both greenhouse gas emissions and removals from land use, land use change, and forests. The implication for users is that C-ROADS now shows dynamic land use emissions, as seen in the graphs “Net Emissions from Land Use” and “Net Emissions from Land Use by Region.” As a result of these improvements, total greenhouse gas emissions may no longer remain flat when setting an Emissions Peak Year, as shown in this scenario.
The Prevent Deforestation input now not only slows deforestation, but also reduces mature forest degradation—the deterioration of forests over 100 years old due to harvesting. Mature forests are crucial as they store a large carbon stock that, if harvested, can release significant emissions.
C-ROADS now accounts for bioenergy emissions in overall land use emissions, stemming from the inextricable link between forest carbon and the carbon in bioenergy. Bioenergy emissions now appear in the “Net Emissions from Land Use” graphs. As a result, when the Prevent Deforestation input is set to 100%, land use emissions won’t entirely be eliminated. Previously, bioenergy emissions were accounted for in “CO2 Emissions from Energy,” which is now “CO2 Emissions from Fossil Fuels.” There is also a newly added graph “Net Emissions from Land Use without Bioenergy,” which can be used to isolate land use emissions and compare the results to other models.
In addition to the modeling updates to C-ROADS, the accompanying materials and resources have been revised to reflect these changes. Here is a list of the updated materials:
While the biggest changes from the June 2023 release are to the En-ROADS simulator (read more), relevant updates have been made in C-ROADS to keep both tools consistent.
Burke, M., Davis, W.M. & Diffenbaugh, N.S. (2018). Large potential reduction in economic damages under UN mitigation targets. Nature 557, 549–553. ↩