The study looked at how a natural climate pattern called the quasi-biennial oscillation (QBO) affects the strength of the polar stratospheric vortices in the Arctic and Antarctic. By using a new model that better represents this pattern, researchers found that the QBO can impact the variability of the polar vortices in both hemispheres. They also discovered that warm pool El Nino events, combined with the easterly phase of the QBO, can speed up the breakup of the Antarctic polar vortex. The study suggests that these natural phenomena, along with factors like ozone recovery and greenhouse gas concentrations, play a role in the timing of the polar vortex breakup.