Global climate action is not currently aligned with staying within remaining global cumulative carbon dioxide (CO2) budgets (GCBs) corresponding to the Paris Agreement temperature limits of “well below 2°C” and making efforts toward a lower limit of 1.5°C over pre-industrial. Moreover, GCB estimates depend critically on also achieving commensurate reductions in emissions of nitrous oxide (N2O) and in methane (CH4). Societal well-being and economic growth continue to be highly dependent on climate polluting inputs – fossil fuels for energy, cement and steel for infrastructure, and nitrogen inputs to agriculture. The research project Society-wide Scenarios for Effective Climate Change Mitigation in Ireland (SSECCM) was a one-year, preliminary desk study undertaken to inform implementation of Irish policy on climate mitigation in the context of EU and Paris Agreement objectives. It evaluated international studies of society-wide, long-term climate action scenarios, identifying relevance to the specific situation in Ireland. While CO2 remains the single most important greenhouse gas to consider, emissions of CH4 and N2O also make a significant contribution to global climate disruption . The latter two are especially important to Ireland because, though CO2 remains the dominant GHG, we have comparatively high emissions of these other GHGs, primarily from ruminant livestock agriculture. A new open-source spreadsheet tool, “GHG-WE”, was developed for the project and has also been made available online . This tool incorporates GWP* (modified Global Warming Potential), a new, recently developed, metric to better represent the combined climate effects of different greenhouse gases. This enables comparative national-level “warming-equivalent” analysis of society-wide and sectoral policy alternatives. An additional tool, a “Methane Warming Calculator” has also been developed and released for simplified, CH4 only, scenario exploration . The collected supporting literature is now publicly available in an online bibliographic database to support future research .