For an introduction to the En-ROADS Baseline Scenario, visit the En-ROADS User Guide.
In the landscape of global energy-land-climate model scenarios, the En‑ROADS Baseline Scenario is most comparable to the NGFS Current Policies Scenario produced by three large Integrated Assessment Models and used in the IPCC reports.
A key procedure in testing our simulators involves comparing their results with other models, particularly the Integrated Assessment Models (IAMs) used by the Intergovernmental Panel on Climate Change (IPCC). IAMs aid scientists and policymakers in understanding climate change dynamics and human impact. By comparing against standardized scenarios used by IAMs, we test assumptions and build confidence that the simulator’s results reflect the best understanding of the scientific literature. To learn more about confidence building and testing in En-ROADS, read the En-ROADS Simulator Science page.
Whereas the previous 2022 En-ROADS Baseline Scenario was calibrated to a no-climate-policy scenario from the Shared Socioeconomic Pathways (the SSP2 Baseline), the current version of En-ROADS is now compared to a newer set of standardized scenarios created by the Network for Greening the Financial System (NGFS)1.
The NGFS is an international consortium of central banks and financial institutions, and their scenarios contributed to the most recent IPCC Assessment Report (AR6 2022). The NGFS Current Policies Scenario assumes that the only policies that continue into the future are policies that were implemented around the end of 2019. This is similar to the assumptions in the En-ROADS Baseline Scenario, making it a useful comparison. Three different integrated assessment modeling teams contributed to the NGFS scenarios and generated their own versions of the NGFS Current Policies Scenario.
The graph below compares greenhouse gas emissions in the 2024 En-ROADS Baseline Scenario to the three IAMs that evaluated the NGFS Current Policies Scenario. The En-ROADS Baseline Scenario uses different assumptions than the IAMs—for example, population in the En-ROADS Baseline Scenario is higher because it follows United Nations population projections, and the carbon prices in the NGFS Current Policies Scenario grow higher than the carbon price in the En-ROADS Baseline Scenario.
Greenhouse gas net emissions in En-ROADS include CO2 emissions from bioenergy. In contrast, the IAMs modeling the NGFS scenarios appear to exclude bioenergy emissions from their accounting of greenhouse gas emissions. Therefore for comparison purposes in the graph below, the thick blue line shows greenhouse gas net emissions in En-ROADS including CO2 from bioenergy, while the thin blue line shows En-ROADS greenhouse gas net emissions excluding CO2 from bioenergy.
The IPCC’s Sixth Assessment Synthesis Report (2023) gives a range of greenhouse gas emissions for implemented policy scenarios, which include the NGFS Current Policies Scenario (graph below). In terms of global net greenhouse gas emissions, the En-ROADS Baseline Scenario is at the higher end of the range of scenarios in the “Implemented Policies” category due to differences in assumptions about the cascading effects of policies and model dynamics.
Changes to the En-ROADS Baseline Scenario
We routinely update En-ROADS as new science and data become clear and vetted. Occasionally this involved changes to the Baseline Scenario itself. There was a significant update to the Baseline Scenario in June 2023 which is documented here.
What if I disagree with some of the assumptions in the En-ROADS Baseline scenario?
Researchers draw different conclusions about the underlying parameters that compose baseline scenarios. We encourage curious users to vary the assumptions in En-ROADS under the Assumptions menu. There you can change factors tied to the climate, economy, land use, and energy system to explore how sensitive the model is to their changes. We picked one set of assumptions to be our default in the En-ROADS Baseline Scenario, but users can select a different suite of assumptions as a starting point, and then test policies and engage their audiences from there. The assumptions can be accessed by clicking on Simulation in the top menu bar of En-ROADS and selecting Assumptions.
Further information can be found in the En-ROADS Technical Reference.
1. Network for Greening the Financial System. (2023). NGFS scenarios for central banks and supervisors.
The NGFS scenarios were created to be a “common starting point for analyzing climate risks to the economy and financial system.” Three integrated assessment modeling teams contributed to the NGFS scenarios: PIK REMIND-MAgPIE, JGCRI/PNNL GCAM, and IIASA MESSAGEix-GLOBIOM.↩