Document MESSAGEix workflows for paper "unpack COP28"

[yiyi1991]

This page consolidates a brief documentation of how the MESSAGE modeling work is applied in the upcoming stand-alone paper led by Alaa.

• One-sentence introduction:
  it undertakes a systematic evaluation of the COP28 commitments. We examine how different plausible interpretations of the Article 28 commitments align with pathways consistent with limiting warming to 1.5°C.

• Rolling title:
  Unpack COP28

• Who is involved:
  11 authors; Alaa, Yiyi, Meas on the key workflows; Shotaro, Sid, and Oliver on providing the net-zero fossil application; and Matt, Volker, Carl

• Branch:
  https://github.com/iiasa/gst-bespoke-scenarios
  Private for now. Public after the net-zero fossil paper led by Shotaro is released.

• Details of the model application:
  We included 4 dimensions that reflect the range of plausible interpretations of what “net-zero” could mean under Article 28.
  Net zero of what types of emissions – whether the net-zero goal applies to CO₂ emissions only or to all GHGs (functions here);
  Scope of emissions covered – whether the target includes energy-related emissions only or also accounts for emissions from industrial processes or other relevant sources;
  Net zero where – in Annex I regions or non-Annex-I regions, or globally;
  Level of effort to phase out fossil fuels – representing the year by which a net-zero primary fossil fuel can be achieved.
  Finally by which year (2050, 2060, etc.). Thus 172 scenarios in all.
  Scenario config see here.

• Scenario identifier:
  e.g., model: net_zero_accounting, scenario: ssp1.5c_v6.1_dac-ccs_sd_a2050CO2_na2070CO2_zf2070
  (starting scenario SSP2_low, version 6.1, energy supply and demand emissions only and industrial process emissions not included, reaching net zero CO2 in Annex I regions by 2050, reaching net zero CO2 in non-Annex-I regions by 2070, reaching net zero primary fossil fuels globally by 2070)

• Starting scenario:
  Three options: NGFS_phase_5_1p5c_scenario, SSP2_low, SSP_LED_low(for net zero fossil)
  Can be shifted here.

• Timeline:
  paper submission after Sep 2025 (after SSP scenarios are finalized and released)

• Contact: scenario-design-related -> Alaa, model-application-related -> Yiyi, Meas

• SharePoint folder: NA

This issue will be closed once the paper is released.

Edited July 23, 2025.