Although lifespan changes in cognitive performance and Flynn effects have both been well documented, there has been little scientific focus to date on the net effect of these forces on cognition at the population level. Two major questions moving beyond this finding guided this study: (1) Does the Flynn effect indeed continue in the 2000s for older adults in a UK dataset (considering immediate recall, delayed recall, and verbal fluency)? (2) What are the net effects of population aging and cohort replacement on average cognitive level in the population for the abilities under consideration? First, in line with the Flynn effect, we demonstrated continued cognitive improvements among successive cohorts of older adults. Second, projections based on different scenarios for cognitive cohort changes as well as demographic trends show that if the Flynn effect observed in recent years continues, it would offset the corresponding age-related cognitive decline for the cognitive abilities studied. In fact, if observed cohort effects should continue, our projections show improvements in cognitive functioning on a population level until 2042--in spite of population aging. (Contains 1 table and 6 figures.)