Stratospheric ozone protects life from harmful ultraviolet radiation from the Sun. The Montreal Protocol, enacted to prevent ozone depletion from human activity, halted declines in column-integrated ozone in the 1990s; the upper stratosphere is recovering, but lower stratospheric trends are unknown. I will present clear evidence that lower stratospheric ozone continues to decline, preventing total ozone recovery. However, the result contradicts expectations given our understanding of these factors and, with no clear understanding of why this trend has emerged, implies that the problem of ozone depletion is not yet fully solved. The decline may impact future estimates of ozone layer recovery, and among other things, surface levels of solar ultraviolet radiation.