by Niklas Höhne, NewClimate Institute, and Matthew Gidden, Climate Analytics
The recent wave of national net zero greenhouse gas emissions targets gives hope that Paris Agreement goals can be reached. This was the subject of two different reports late last year, by the Climate Action Tracker and the UNEP Emissions Gap report.
National net zero emission targets could, if fully implemented, reduce best estimates of projected global average temperature increase to 2.0–2.4 °C by 2100, bringing the Paris Agreement temperature goal within reach.
The work is now confirmed in a comparison of the calculations by the Climate Action tracker and the UNEP Emissions Gap report published in Nature Climate Change.
A total of 131 countries are discussing, have announced or have legally-adopted targets to reduce their greenhouse gas emissions to net zero. They together cover 72% of global emissions. While of course these 131 net zero statements vary widely in their level of commitment, from a political statement to being enshrined in legally binding legislation, both research groups considered them all together for the sake of this calculation.
This work has now been published in a peer reviewed paper in Nature Climate Change in a combined effort by the contributors to both reports, comparing the two independent methods used to calculate the impact of the targets. The authors include many in the CAT team, alongside two UNEP Gap Report authors Michel den Elzen of PBL and Joeri Rogelj of Imperial College (see end of article).
Consistent across both the CAT and UNEP estimates is the relative magnitude of the overall effect of the net zero targets: reducing warming by ~0.8–0.9°C, the single-largest reduction in overall warming estimates by either organisation since the inception of the Paris Agreement in 2015.
The CAT has been assessing the warming impact of government pledges since 2009; the first UNEP Gap Report was released in 2011, and the CAT has contributed to this work.
The paper notes that the targets could substantially lower projected warming compared with current policies (2.9-3.2˚C) or pledges submitted to the Paris Agreement (2.4-2.9˚C).
However, the most important point now is that the “good intentions” of the net zero announcements must now be translated into short term, 2030 action, to keep the Paris Agreement’s 1.5˚C goal within reach.
Existing policies and targets that drive short-term action are not at all consistent with the announced net zero targets, as evidenced in the CAT’s latest assessment, which sees an enormous 2030 emissions gap still wide open.
Authors: Niklas Höhne (NewClimate Institute), Matthew Gidden (Climate Analytics), Michel den Elzen (PBL), Frederic Hans (NewClimate Institue), Claire Fyson (Climate Analytics), Andreas Geiges (Climate Analytics), Louise Jeffery (NewClimate Institute), Sofia Gonzales-Zuñiga (NewClimate Institute), Silke Mooldijk (NewClimate Institute), William Hare (Climate Analytics) and Joeri Rogelj (IIASA).