  Holocene (the last 12,000 years) temperature variation, including the
transition out of the last Ice Age to a warmer climate, is reconstructed at
multiple locations in southern Finland, Sweden and Estonia based on pollen
fossil data from lake sediment cores. A novel Bayesian statistical approach is
proposed that allows the reconstructed temperature histories to interact
through shared environmental response parameters and spatial dependence. The
prior distribution for past temperatures is partially based on numerical
climate simulation. The features in the reconstructions are consistent with the
quantitative climate reconstructions based on more commonly used reconstruction
techniques. The results suggest that the novel spatio-temporal approach can
provide quantitative reconstructions that are smoother, less uncertain and
generally more realistic than the site-specific individual reconstructions.
