Siberian scientists assessed how vegetation of the Arctic wetlands behaves under the influence of industrial emissions from Norilsk and climate change. Until the nineties of the last century, trees and shrubs were damaged and died due to high sulfur emissions. But since the 2000s, after a decrease in pollution and an increase in summer and autumn air temperatures, they began to recover. The results of the study are published in the journal Water.

The Siberian Arctic is located in a warming hotspot, warming much faster than the rest of the planet. Along with this, forest-bog phytocenoses, located in the impact zone of the Norilsk copper-nickel industry, are strongly affected by technogenic pollution. Moreover, in 2020, there was a release of oil products in the area.

Siberian scientists from the Federal Research Center "Krasnoyarsk Science Center of SB RAS", Siberian Federal University, TSU and M.F. Reshetnev SibSAU assessed the joint impact of climate warming, long-term pollution with sulfur dioxide emissions and the recent man-made disaster associated with a diesel fuel spill on the tree and shrub flora in the permafrost zone near Norilsk.

The researchers concluded that, along with the chronic impact of sulfur dioxide emissions, the growth of Siberian larch in the studied areas is limited by air and soil temperatures, as well as excessive waterlogging. A decrease in the radial growth of larch trees, their damage and death have been observed since the 1950s and reached their maximum values in the 1990s. The high spring temperature negatively affects the activity and survival of trees. Experts note that early spring heat leads to a decrease in growth, activating metabolism in the absence of soil moisture. The “awakened” tree (or rather, its aerial part) begins to grow, while the roots located in the still frozen soil cannot provide the tree organism with life-giving moisture. As a result, one observes drying of young shoots and their damage, along with prematurely blooming needles, due to late spring frosts.

However, starting from the 2000s, the vegetation in this area of the Arctic began to recover. In particular, the researchers noted an increase in the growth of larch trees, as well as increasing trends in the gross and net productivity of vegetation cover. This was due to the reduction of sulfur dioxide emissions, climate warming, lengthening of the growing season and migration to the damaged areas of sulfur dioxide-resistant trees, shrubs and herbaceous plants. It is assumed that industrial emissions of nitrogen oxides could also contribute to the increase in productivity, transforming into nitrogen fertilizers. At the same time, scientists assessed the impact of the fuel spill in 2020 on vegetation as insignificant.

“Emissions from the Norilsk industry have caused the largest loss of vegetation beyond the Arctic Circle. In addition, these areas are experiencing the strongest impact of climate warming. We studied the effect of a combination of these factors on the flora of the Arctic zone. A strong negative side effect of the Norilsk industry is air pollution with sulfur dioxide, dust and heavy metals. This significantly worsened the ecological situation and, in particular, had a negative impact on the vegetation cover. However, we assume that current climate changes may mitigate the adverse effects of pollution on the growth of trees and shrubs. In addition, some species of woody plants (in particular, willows and birches) turned out to be more resistant to technogenic pollution. We assume that they will play an important role in restoring the vegetation cover in the damaged areas in the vicinity of Norilsk,” said Candidate of Biological Sciences, senior researcher at the  V.N. Sukachev Institute of Forest SB RAS, Ilya Petrov.