C-ROADS User Guide

C-ROADS Model Version History🔗


December 2023 Release🔗

Interface Changes🔗

  • Changed the "CH4 Emissions" graph to show only emissions from anthropogenic sources, to match the behavior of that graph in En-ROADS.
  • Removed the "Anthropogenic CO2 Emissions and Removals" graph. (With the new model structure for land use that was added in the June 2023 release, this graph no longer adds value.)
  • Updated the value of the NDC dot to reflect the latest data from the latest UNEP Emissions Gap Report (2023). The NDC dot is available by selecting the "Show UN Pledges (NDCs)" option in the "Greenhouse Gas Net Emissions" graph actions menu.
  • Changed the start year for input sliders to 2024.

Model Upgrade🔗

  • C-ROADS model to version 23.12.0

August 2023 Release🔗

Interface Changes🔗

  • Added a link item to the Help menu that opens the C-ROADS Model Technical Reference.
  • Changed the default value of the "Effect of temperature on rate of CO2 and CH4 emissions from permafrost and clathrates" slider from 0.1% to 0.5% (per year per ºC).

Model Upgrade🔗

  • C-ROADS model to version 23.8.0
  • Removed the temperature feedback on crop yield.
  • Updated various parameters using values from the latest IPCC AR6 report, including greenhouse gas time constants, radiative forcing efficiencies, and global warming potential parameters.
  • Updated GDP data through 2022 using the latest 2023 World Bank data.
  • Updated PRIMAP historical emissions data through 2021 with the latest update (v2.4.2, 2023).
  • Updated NOAA concentration and radiative forcing data through 2022.
  • Updated GISTEMP and Hadley temperature data through 2022.
  • Updated NASA sea level rise data through 2022.
  • Reduced the download size of the model (by ~20%) by eliminating some unneeded datasets.

June 2023 Release🔗

This update includes major improvements and additions, including a new Baseline Scenario that accounts for the economic impact of climate change; new graphs; and model improvements to the land, forests, and bioenergy sectors. To learn more about the update, visit the C-ROADS June 2023 Release Summary page.

Interface Changes🔗

  • Added tooltips to the "Temperature Increase in 2100" figures to allow for temperature values to be viewed out to two decimal places.
  • Renamed "CO2 Emissions from Energy" graphs to "CO2 Emissions from Fossil Fuels".
  • Renamed "Net Land Use & Forestry Emissions" graphs to "Net Emissions from Land Use".
  • Added the "Net Emissions from Land Use without Bioenergy" graph.
  • Added "Climate change slows economic growth" toggle to Assumptions > Growth.
  • Added and updated various options under the Assumptions view to reflect updated modeling.
  • Updated start years to 2023.

Model Upgrade🔗

  • Updated Baseline Scenario: Several model adjustments have lowered the baseline temperature in 2100 to 3.3°C/5.9°F. More details on the Baseline Scenario here.
    • Economic growth in the Baseline Scenario is now affected by the economic impact of climate change via a damage function. The damage function in the Baseline Scenario is from Burke et al. 2018 and can be turned off in the Assumptions view. More details on the damage function here.
  • Land, Land Use Change, and Forestry: Added a more detailed model of the terrestrial carbon cycle. The movement of carbon between the atmosphere, biomass, and soil now depends on the type of land and the age of forests, meaning that land use, land use change, and forestry (LULUCF) emissions are calculated endogenously. More details on land here.
    • Four land use categories are modeled (forest, farmland, tundra, and other) plus three ages of forest, with the area and amount of carbon in biomass and soil for each.
    • Bioenergy now depends on land availability (see below).
  • Bioenergy: Linked the growth and harvest of fuel for bioenergy into the new terrestrial carbon cycle (see above) and explicitly modeled the regrowth of biomass after harvest. Bioenergy removes biomass from the land, affecting the movement of carbon between the air, biomass, and soil. More details on bioenergy here.
  • Other model improvements:
    • C-ROADS model to version 23.6.0
    • Updated the behavior of the "Prevent Deforestation" input so that it now includes mature forest degradation.
    • Improved the model structure so that bioenergy emissions are now included in land use emissions, instead of energy emissions.

November 2022 Release🔗

Interface Changes🔗

  • Norwegian translation: The C-ROADS interface is now available in Norwegian (Norsk Bokmål).
  • Updated the Population slider range to reflect the latest World Population Prospects data from the United Nations.
    • The previous range was 9.1 to 13.2 billion, with a baseline value of 10.9 billion.
    • The updated range is 8.8 to 12.4 billion, with a baseline value of 10.4 billion.

Model Upgrade🔗

  • C-ROADS model to version 22.11.0
  • Updated population (historical and projection) data using the latest 2022 World Population Prospects data from the United Nations.
  • Updated GDP data (through 2021) using the latest 2022 World Bank data.
  • Updated greenhouse gas concentration data (through 2021) using the latest NOAA data.
  • Updated historical temperature change data (through 2020) using the latest GISTEMP and HADCRUT datasets.
  • Updated CO2 emissions data (through 2020) using Global Carbon Budget (2022). This captures the CO2 emissions dip and rebound due to COVID-19.
  • Fixed historical sea level rise datasets to show annual average values instead of selected data points.
  • Corrected an error in GDP data that led to slightly inaccurate historical results.
  • Corrected the calculation of "Probability of ice-free arctic summer at least once before 2100", which previously produced inaccurate results in certain scenarios.

May 2022 Release🔗

Interface Changes🔗

  • Restored the "CH4 Concentration" graph.
  • Added sea level rise maps to the macOS and Windows apps.
  • Fixed an issue where the graphs and temperature would show incorrect data when opening a shared scenario.

Model Upgrade🔗

  • C-ROADS model to version 22.5.0

March 2022 Release🔗

Interface Changes🔗

  • Upgraded interface: This release includes significant upgrades to the visual interface. The appearance and content of C-ROADS is now more consistent with our newer En-ROADS model, with changes including a refreshed color palette, updated graph and menu bar features, and a new font choice. For a walkthrough of the new C-ROADS interface and guidance on how to use the model, watch this tutorial video or read the blog post that announces the new release.
  • New menu bar features: In addition to some rearranging of the menu bar items, there are a few key new features included in this release. Users now have the ability to Undo, Redo, and Replay inputs using the newly added buttons in the top menu bar. Additionally, you are now able to save and share your custom C-ROADS scenarios using the Share Your Scenario button in the top right corner of the interface. Scenario links can be shared on social media, via email, and copied.
  • Climate impact graphs: Five new bar graphs have been added under the Graphs > Impacts menu showing the effects of climate change:
    • Population Exposed to Sea Level Rise
    • Probability of Ice-free Arctic Summer
    • Decrease in Crop Yield from Temperature
    • Species Losing More than 50% of Climatic Range
    • Additional Deaths from Extreme Heat
  • Sea level rise maps: Flood risk maps from Climate Central have been integrated into C-ROADS under Graphs > Impacts. These maps display the land areas that are at risk of flooding due to sea level rise, as well as the land that can be saved by actions made in the Current Scenario in C-ROADS. More details of this new feature are available in our blog post.
  • Graph actions menu: A new contextual menu is available by clicking the "three dots" icon to the right of a graph title. The menu reveals actions related to the graph:
    • Show Description
    • View Larger
    • View in New Window
    • Copy Data to Clipboard
  • UN pledges: When viewing the "Greenhouse Gas Emissions" graph, an extra item will appear when clicking the graph actions menu. "Show UN Pledges (NDCs)" reveals a dot on the graph demonstrating the amount of greenhouse gas emissions in 2030 if all countries fulfill their NDC pledges.

Model Upgrade🔗

  • C-ROADS model to version 22.3.0
  • Note that starting with this release, the model version number is now based on the date of the release (for example, 22.3 refers to the third month of 2022).
  • Changed the aggregation to move 4 countries (Iceland, Norway, Switzerland, and the United Kingdom) from the EU grouping to Other Developed Nations.

May 2021 Release🔗

Interface Changes🔗

  • Translation into Portuguese: The C-ROADS user interface is now available in Portuguese.
  • Structural upgrades to the user interface: We have updated the underlying architecture of C-ROADS so that the model runs inside the browser. The simulation runs much faster, and therefore graphs update instantaneously when sliders are moved or numbers are entered into the input fields.
  • Improved the positioning and responsiveness of the Large Graph and 2100 Data Table windows. The plots and data in these windows now update automatically when new values are entered into the main window.

April 2021 Release🔗

Interface Changes🔗

  • Added two new graphs for Global Cumulative CO2 for 2000-2100 and 1990-2015 (historical data) to the CO2 Emissions menu for all three simulation levels.
  • Added new "Historical Global Net Greenhouse Gas Emissions" and "Global Nonforest Greenhouse Gas Emissions" graphs to the Greenhouse Gas Emissions menu for all three simulation levels.
  • Relocated the graphs for Cumulative CO2 from the greenhouse gas (GHG) menu into the CO2 Emissions menu for 3-Region and 6-Region levels of simulation aggregation.

Model Upgrade🔗

  • C-ROADS model to version 1.36

February 2021 Release🔗

We have created a short description video about C-ROADS to provide a quick orientation to the simulation.

Interface Changes🔗

  • Changed all mentions of the 18th or 19th century to "from 1750" or "from 1850", respectively.
  • Corrected the "Sources of CO2 Removals" graph to read "Sources of Carbon Removals" and corrected the y-axis label to indicate "Gigatons carbon/year".
  • Relocated the graph, "Global Cumulative CO2 Emissions from 1900-2017" under the Energy CO2 Emissions menu where it belongs.
  • Removed the outdated "Show Paris Outcomes" feature under the "View" menu. It will be replaced in a future model update.

Model Upgrade🔗

  • C-ROADS model to version 1.33
  • Updated data file with new HADCRUT5 dataset.
  • These data updates lead to a temperature change adjustment from 0.16°C to 0.05°C as outlined in more detail in the related article on the En-ROADS baseline updates.
  • Updated historical CO2 emissions with data from the Global Carbon Budget (2020) and for other GHGs with PRIMAP-hist (2019).
  • Improved and simplified CH4 concentration calibration to avoid unnecessarily introducing more uncertainty in response to CH4 concentration effects on uptake and to include updated PRIMAP data.

December 2020 Release🔗

Interface Changes🔗

  • Changed the application name from "C-ROADS World Climate" to simply "C-ROADS".
  • Changed the phrase "Business as usual" and "BAU" to "Baseline" across the interface.
  • Changed the minimum year for all inputs to 2021.
  • Improved the layout to make room for larger graphs.

Model Upgrade🔗

  • C-ROADS model to version 1.32
  • Updated the model to align with the baseline scenario of En-ROADS, which results in a temperature increase in 2100 of 3.6°C (6.5°F).
  • Temperature change is now reported relative to 19th century instead of 18th century.
  • Adjusted baseline greenhouse gases per GDP parameters to better reflect recent trends, and updated projections in energy and land use.
  • Updated the long term GDP per capita rate from 1%/year to 1.5%/year but achieved sooner, i.e., decreased convergence time.
  • Changed the last GDP historic year from 2018 to 2019; it is now in $2017 PPP (purchasing power parity) instead of $2011 PPP.

August 2020 Release🔗

Interface Changes🔗

  • Added "Economic Growth" and "Population Growth" sliders in the Assumptions panel.

Model Upgrade🔗

  • C-ROADS model to version 1.29
  • Fixed the behavior of "Prevent Deforestation" for regions with net negative land use emissions.

May 2020 Release🔗

Interface Changes🔗

  • Added a new menu item, Help > Release Notes, to access model release notes.

Model Upgrade🔗

  • C-ROADS model to version 1.26
  • Updated historical data through 2018 for GDP and CO2.
  • Updated F-gases to be consistent with SSP2 (as with En-ROADS).

March 2020 Release🔗

Interface Changes🔗

  • Changed afforestation and deforestation inputs to be a percentage of the maximum value.
  • Added partial Korean localization.
  • Changed MIT link to the Sustainability Initiative.
  • Added links to new Climate Interactive resources.
  • Fixed resizing behavior of the large graph window.
  • Doubled the size of labels on the large graph window.
  • Improved size of the temperature panel fonts.
  • Removed spurious scrollbars in some layouts.
  • Changed the graph menu title from "Model Validation" to "Model Comparison".

Model Upgrade🔗

  • C-ROADS model to version 1.22
  • Updated historical values.
  • Updated start years to 2020.
  • Improved the way Afforestation is simulated.

March 2018 release🔗

Interface Changes🔗

  • Refined the layout of the temperature in 2100 panel.
  • Added Paris outcome reference scenarios to more graphs.
  • Fixed the desktop app so that it quits when the window is closed on macOS.
  • Added shortcuts to all menus in the desktop app on Windows.

Model Upgrade🔗

  • C-ROADS model to version 1.09

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