What makes a good national net zero target? Our ten-step evaluation methodology, explained

The last year has seen a wave of national net zero target announcements. This has triggered an important discussion among policy makers, civil society, and academics on the usefulness, scientific robustness, and real-world impact of these targets.[i]

At their best, well-designed and ambitious net zero targets are key for reducing global carbon dioxide and other greenhouse gas emissions to net zero around 2050 and 2070, respectively. This is necessary to keep to the Paris Agreement’s 1.5°C temperature limit. Ambitious net zero targets can also guide the implementation of Paris-aligned actions in the short and medium term, in particular 2030 emission reduction goals.

At their worst, net zero targets are unclear or not backed up by real-world action. Net zero targets can distract from the urgent need for deep emissions reductions if 2030 targets and short-term action are inconsistent with their achievement, allowing governments to “hide” behind aspirational net zero targets. Unless governments start acting now, their chances of achieving net zero will be slim.

Recent analysis by the Climate Action Tracker (CAT) in April 2021 showed that if fully implemented, governments’ net zero targets can make a substantial dent in future warming levels, but also warned that steep near-term mitigation efforts are needed to make that feasible. As of May 2021, a total of 131 countries had adopted or announced net zero targets. These countries cover about 73% of global emissions and include key emitters like the United States of America, China, and the European Union (see Figure 1).

Our assessment found that global warming by 2100 could be as low as 2.0°C if all the net zero targets announced or under consideration (but not yet submitted to the UNFCCC) were to be achieved – still far from 1.5°C but representing substantial progress. This stands in stark contrast to the expected global warming levels under submitted Paris Agreement targets and pledges (2.4°C) and currently implemented policies (2.9°C).

There are many uncertainties in estimating the impact of net zero targets, not least because underlying assumptions may not be clear, the targets may not be comprehensive, or their legal status and likelihood of being fully implemented are uncertain.

There is a clear need for a nuanced assessment of incoming national net zero targets to understand their scope, architecture, and transparency. Without such scrutiny, there is a risk that poorly backed up net zero claims could render these targets meaningless.

Figure 1: Share of GHG emissions covered by countries that have adopted or announced net zero emission targets (agreed in law, as part of an initiative, or under discussion). Compilation based on ECIU (2021) as of 29 April 2021 complemented by CAT analysis. Emissions data for 2017 taken from EDGAR emissions database (EDGAR, 2019).