The effect of climate change on vegetation, isoprene emissions and surface ozone levels was investigated using a global three-dimensional general circulation model coupled to a dynamic vegetation and chemistry models. Integrations for the 1990s and 2090s were performed. Isoprene emissions increased from 549 Tg yr-1 (1990s) to 736 Tg yr-1 (2090s) as a result of climate change with fixed vegetation. However, the isoprene emissions only increase to 697 Tg yr-1 in the 2090s when vegetation changes were included. Surface ozone levels rose by 20--30 ppbv in some locations with fixed vegetation owing to increases in precursor gases, but only by 10--20 ppbv if the vegetation changes were included. Ozone levels in parts of China, Korea and the eastern USA are predicted to exceed the World Health Organisation health limit of 60 ppbv, however, when changes in vegetation are accounted for, a much smaller area exceeds this limit.