Defining Net-Zero and Climate Recommendations for Carbon Offsetting

Anthropogenic global warming (AGW) requires net-zero human greenhouse gas (GHG) emissions to stabilize the climate. As achieving zero emissions is unrealistic, offsetting is necessary to achieve net-zero (emissions minus offsets). Organizations need to become carbon-neutral, both by reducing emissions and by removing atmospheric CO2. However, much of the language used in discourse surrounding carbon-neutrality and net-zero is vague; more rigorous definitions are required. Currently, emissions are “neutralized” through “deemed offsets,” which can include GHG sinks, reductions, and allowance schemes. Metrics are employed to determine offsetting amounts.
We extend current practice using a “do no harm” principle to better account for different GHGs’ climate impacts. We examine emissions reduction and the appropriate use of offsetting, including challenges such as carbon storage robustness. We illustrate these guidelines using the PAS 2060 carbon-neutrality standard.
In summary, while offsetting is required for climate stabilization, schemes differ in their capacity to halt AGW. High-quality offsetting is required to stabilize warming; we discuss key physical considerations.