Current understanding suggests that radiative forcings over the course  of an 11-year solar cycle are in phase with related influences on  climate. Recent satellite data have revealed, however, that there seems  to be a surprising spectral component to solar variability, at least in  the declining phase of the current solar cycle: UV radiation decreases  strongly while visible radiation increases. Joanna Haigh and colleagues  now show that these spectral variations — when incorporated into a  radiative-photochemical model — lead to decreases in ozone below 45  kilometres and increases above. As a consequence of the ozone changes,  radiative forcing of surface climate is out of phase with solar  activity. This finding, although based on a short record from a  potentially anomalous solar cycle, suggests that a major revision to our  current understanding of solar forcing of climate may be in order.