The United Nations Environment Programme’s (UNEP) new “Limiting Overshoot” report states that global warming will exceed the 1.5-degree-Celsius threshold above pre-industrial levels. The report focuses on keeping the overshoot as short and limited as possible: Temperatures are expected to rise first, reach a peak and then be brought down. Since the current pace of emissions reductions is insufficient, greenhouse gas emissions need to be rapidly reduced and carbon dioxide removed from the atmosphere. Net-zero targets alone will not be enough. Carbon dioxide removal methods will be used alongside, not instead of, direct emissions cuts. Overshoot does not mean abandoning climate policies.
Why it matters
The framework set out by the report shows that climate policy cannot be tied solely to long-term net-zero targets. For decision-makers, the issue is to plan carbon dioxide removal from the atmosphere as a complement to efforts to accelerate emissions reductions, rather than substituting one approach for the other. Instead of accepting the breach of the 1.5-degree threshold as inevitable and relaxing policies, this approach puts limiting the scale and duration of the overshoot at the center. However, questions remain open as to how far the target highlighted by the report can be achieved, how quickly emissions will be reduced and within what limits carbon dioxide removal applications will be used. For this reason, the development is generating a policy debate focused less on the existence of climate targets than on how they are implemented.