Ecological and conceptual consequences of Arctic pollution

Abstract

Although 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.

The influence of decision-making in tree ring-based climate reconstructions

“…Relatively warmer measured temperatures prior to circa 1850 CE are possibly biased by the low quality and quantity of early instrumental observations 19 , whereas relatively cooler reconstructed temperatures after circa 1990 CE are symptomatic for the ‘Divergence Problem’ in dendroclimatology 20 : the apparent decoupling between TRW chronologies and rising temperature measurements since around the 1970s 21 . Recent investigations suggest that methodology-induced challenges of proxy-target calibration, proxy network size, end-effects in time-series composition 22 , as well as industrial pollution 23 , or a combination thereof 20 , can explain the ‘Divergence Problem’. Three reconstructions track the measured warming after 1990 very well (R8–R10), and another three ensemble members reveal just slightly lower temperatures compared to those measured between 1990 and 2000 (R7, R11, R14).…”

Global fading of the temperature–growth coupling at alpine and polar treelines

“…In addition, there is the divergence problem which describes a loss of responsiveness of tree growth to rising growing season temperatures in subarctic regions after the 1960s (Briffa et al, 1998). The low‐frequency component of photosynthetic solar radiation has also been shown to explain part of the divergence problem in subarctic regions where tree growth is mainly driven by summer temperature (Kirdyanov et al, 2020). Such complex growth responses to temperature rise may depend on local climate conditions, treeline features (e.g., shape, size), and age structure or species‐specific traits, making some treelines less valuable monitors of climate warming than expected (Davis et al, 2020).…”

Toxic Metal Species and ‘Endogenous’ Metalloproteins at the Blood–Organ Interface: Analytical and Bioinorganic Aspects

“…Certain anthropogenic activities, such as the metallurgy industry, are known to dramatically affect ecosystems [ 2 ]. In northern Siberia, for example, 24,000 km 2 of Taiga (roughly 1/3 of the size of Austria) represent the most polluted area in the world where there is essentially no tree growth due to the emission of 1.8 million t of pollutants (98% SO 2 as well as Cu and Ni) in 2018 [ 3 ]. Anthropogenic inorganic pollutants that are released into the global environment due to technological advances and fossil fuel consumption can also enter the biological system by different exposure routes to adversely affect human health.…”