Early Methane Mitigation Critical to Preserving Arctic Summer Sea Ice

Abstract:

Methane mitigation is a key component of achieving international temperature targets and plays a large role in limiting near-term warming. However, little is known about how methane mitigation benefits other aspects of the climate system. Here we show that early implementation of feasible methane mitigation is essential to avoiding the loss of Arctic summer sea ice (ArSI), using joint kernel density estimation between a range of existing ArSI temperature thresholds and an ensemble simulation of future global mean temperature. We find that if technically feasible methane mitigation is pursued in parallel with Paris Agreement Nationally Determined Contribution carbon dioxide (CO2) goals, we can delay the likelihood of surpassing the ArSI tipping point by nearly 45 years and avoid likely tipping until the end of the century. Furthermore, deeper cut in CO2 together with technically feasible methane mitigation can preserve ArSI beyond this century. However, early implementation of methane mitigation is critical in protecting ArSI. This research highlights the need to explicitly consider other aspects of the climate system besides temperature when evaluating the benefit of a certain mitigation strategy, given that the overall climate benefit is not proportional to global mean temperature.