December 2020 C-ROADS Update

By Yasmeen Zahar
December 15, 2020

The December 2020 update to C-ROADS includes three significant changes to the modeling and interface of the simulator:

1. A new Baseline Scenario (renamed from “Business as Usual”), which leads to a lower global temperature in 2100 — 3.6°C (6.5°F) instead of 4.1°C (7.3°F). This change arises from:

• Change in the definition of the pre-industrial temperature benchmark. The temperature change in C-ROADS was previously relative to the mid-1700s (to match the approach of other models), and now it is relative to the mid-1800s, a more common time period used in climate policy.
• Improved modeling of non-greenhouse gas forcings, which include those from aerosols (black carbon, organic carbon, sulfates, nitrates, and biomass burning-related), cloud albedo, stratospheric ozone, tropospheric ozone, stratospheric water vapor from methane oxidation, land use, black carbon on snow, volcanic stratospheric aerosol, solar irradiance, and direct forcings from mineral dust aerosol.
• An assessment of the global growth in renewable energy in the En-ROADS simulator resulted in greenhouse emissions reductions being apportioned across regions in C-ROADS.

For more information about the baseline update, please review this technical blog post (the En-ROADS and C-ROADS simulators are rooted in the same baseline modeling) and the C-ROADS Technical Reference.

2. GDP Updates to Modeling:

• Updated last GDP historic year from 2018 to 2019, now measured in $2017 PPP from $2011 PPP.
• Change in long term GDP per capita rate from 1%/year to 1.5%/year, with decreased convergence time.
• Greenhouse gas emissions per GDP parameters adjusted to better reflect recent trends and updated projections in energy and land use.

3. Renaming “C-ROADS World Climate” to simply “C-ROADS” and retiring other versions of the simulator, including C-ROADS Pro and C-Learn.

These new changes are live in the online version of C-ROADS.