In addition to the global temperature outcomes of policies and pledges, the CAT also assesses the expected absolute emissions in 2020, 2025, and 2030 and compares these with benchmark emissions consistent with benchmark pathways in line with the temperature goal in the Paris Agreement.
With the release of the IPCC Special Report on 1.5 °C the CAT updated its benchmark emissions pathways in 2018 (for more info also see here).
The main effect of this update is that 1.5°C-compatible levels for 2030 are lower by about 3 GtCO2e/yr. This is related to the fact that 2030 and post-2030 emissions need to compensate for higher emissions between 2010 and 2020 than the previously used benchmark pathways. These earlier pathways were intended to guide CAT updates on how the world could benefit from early strong global action, which has however not materialised. Now the 2010s decade of delayed climate action needs to be compensated by steeper reductions from 2020 to 2030 and beyond, which can therefore be seen as an expression of lost time in global mitigation.
The IPCC Special Report on 1.5°C shows that steep reductions are urgent, but feasible, and will still deliver the many benefits associated with 1.5°C-compatible pathways in terms of avoided climate-change impacts, as well as cleaner air, increased employment in the renewable energy sector, access to modern energy, etc.
As of December 2018, a substantial gap remains between the levels of emissions in 2025 and 2030 projected in the NDCs submitted to the UNFCCC and the lower levels that would be consistent with the temperature goal in the Paris Agreement.
The benchmark emissions from a 1.5°C compatible pathway are 41 GtCO2e in 2025 and 28 GtCO2e in 2030. Comparing these with the emissions from the pledges and targets submitted by December 2018, which results in total global emissions of 53–55 GtCO2e in 2025 and 54–57 GtCO2e in 2030 the CAT calculates a gap 12–14 GtCO2e in 2025 and 26–29 GtCO2e in 2030.
For comparison, the IPCC’s Special Report on 1.5°C estimated 2030 emissions levels at 52–58 GtCO2e for NDCs, which compared to that Report’s 25–30 GtCO2e 1.5°C-compatible 2030 benchmark suggests an emissions gap of about 28 GtCO2e between the means of both these ranges.
The benchmark emissions from a 2°C compatible pathway are higher (47 GtCO2e in 2025 and 39 GtCO2e for 2030), and comparing these to the global emissions from the pledges and targets quoted above, the gap ranges between 6–9 GtCO2e for 2025 and 15–18 GtCO2e in 2030.
Last updated: 11 December 2018