CARBON BUDGET ANALYSIS WITH THE TIMES-IRELAND MODEL

Second iteration of modelling to support CCAC CBWG

SCENARIO ASSUMPTIONS

Five different Carbon Budgets (CB) for the period 2021-2050 are modelled based on the IPCC assessment of the global Remaining Carbon Budget (RCB). The analysis focuses on the RCBs aligned with 1.5°C to 2°C of global warming with different probabilities. These CBs for Ireland are as follows:

• 450Mt aligned with 67% likelihood of limiting global warming to 2.0°C (IPCC AR6 1150Gt CO2 RCB)

• 400Mt aligned with 1.7°C (33%) (IPCC AR6 1050Gt CO2 RCB)

• 350Mt aligned with 1.5°C (17%) and 2.0°C (83%) (IPCC AR6 900Gt CO2 RCB)

• 300Mt aligned with 1.7°C (50%) (IPCC AR6 850Gt CO2 RCB)

• 250Mt aligned with 1.5°C (33%) and 1.7°C (67%) (IPCC AR6 650-700Gt CO2 RCB)

Carbon budget allocations are as follows:

Two distinct demand projection scenarios are also considered:

• Business as Usual (BAU)

• Low Energy Demand (LED)

We model all five CBs with the BAU demand projection. The lower three CBs (250, 300, and 350Mt) are also modelled with the low energy demand projection. Combining the CB and demand projection pathways, we analyse mitigation pathways across eight scenarios.