Though the effect of pollution on forest health and decline received much attention in the 1980s, it has not been considered to explain the ‘Divergence Problem’ in dendroclimatology; a decoupling of tree growth from rising air temperatures since the 1970s. Here we use physical and biogeochemical measurements of hundreds of living and dead conifers to reconstruct the impact of heavy industrialisation around Norilsk in northern Siberia. Moreover, we develop a forward model with surface irradiance forcing to quantify long-distance effects of anthropogenic emissions on the functioning and productivity of Siberia’s taiga. Downwind from the world’s most polluted Arctic region, tree mortality rates of up to 100% have destroyed 24,000 km² boreal forest since the 1960s, coincident with dramatic increases in atmospheric sulphur, copper, and nickel concentrations. In addition to regional ecosystem devastation, we demonstrate how ‘Arctic Dimming’ can explain the circumpolar ‘Divergence Problem’, and discuss implications on the terrestrial carbon cycle.

We utilize hundreds of TRW samples from living and dead conifers surrounding the Norilsk industrial complex to reconstruct the sequence of events leading up to a historically unprecedented forest dieback and decline, in one of the world’s most polluted regions, since the 1930s. We expand our dendrochronological findings with high-resolution measurements of wood and soil chemistry to quantify the spatiotemporal extent of Norilsk’s devastating ecosystem damage. We develop a process-based forward model of boreal tree growth to detect and attribute the effects of changes in surface solar radiation (see publication for details).

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