2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Scientists have suggested that the Arctic industry has a significant impact on global climate change. They examined the annual rings of hundreds of spruce and larch trees in the vicinity of Norilsk and found that the trees did not grow faster in response to the increase in the average annual temperature. This was due to a lack of sunlight: the emissions from the metallurgical plant brought into the atmosphere a huge amount of aerosols, which made it less transparent. The article was published in the journal Ecology Letters.
One of the generally accepted methods of climate reconstruction is dendrochronological. It is based on the fact that in trees growing in temperate climates with pronounced seasons, wood forms annual rings: at the beginning of the growing season, there is an active growth of conductive tissues, and at the end, more mechanical tissues grow. Then growth stops until the next growing season. By the thickness of the growth rings, one can judge the air temperature and a number of other factors important for the physiology of trees: the number of nutrients, wind and humidity.
The dendrochronological method is very valuable: trees live a long time and can tell about climate changes over the centuries. However, starting in the 1970s, in the zone of temperate and polar climates, climatologists began to observe the so-called problem of divergence: trees ceased to give a sensitive response to an increase in average annual air temperature and, contrary to logic, did not begin to grow faster. This called into question the reliability of the application of the dendrochronological method at high latitudes. Ecologists named the degradation of northern ecosystems due to anthropogenic pollution of the environment as a possible reason for these trends. They noted that the planet's atmosphere has become worse for the transmission of sunlight due to a sharp increase in the concentration of industrial aerosols in it. This phenomenon is called "global dimming".
Alexander Kirdyanov, employee of the Krasnoyarsk Institute of Forest named after Sukachev of the Siberian Branch of the Russian Academy of Sciences and the University of Cambridge, together with colleagues from the Siberian Federal University and other scientific organizations of Britain, Germany, the Czech Republic and Switzerland, conducted a dendroclimatological study of forest-tundra ecosystems in the vicinity of Norilsk. Their goal was to understand how the pollution of the environment by emissions from the Norilsk Combine, combined with the conditions of the polar climate, affected the vital state of local trees. To do this, they laid a transect that stretches across the region from north-west to south-east for 150 kilometers and includes eight test sites. Siberian larch (Larix sibirica Ledeb) was the edificator in the ecosystems through which the transect passed. Siberian spruce (Picea obovata Ledeb) and Daurian larch (Larix gmelinii) also dominated to a high degree. In total, scientists examined 46 living and 503 dead trees.
A - Study area. Test sites are marked with numbers; shades of gray from pale to rich correspond to increasing levels of environmental pollution. B - photographs of trees at sites 4, 5, and 7, where signs of technogenic degradation of ecosystems are noticeable.
The authors relied on the indicator of the tree ring width, which was measured with a resolution of 0.01 millimeter using the LINTAB system and then used to compile tree-ring chronologies. Ecologists also analyzed soil and wood samples for contamination with sulfur, copper and nickel using an X-ray fluorescence method.
The gray numbers above the figures and the dotted vertical lines indicate the main milestones in the development of the Norilsk Combine. A is the percentage of trees at each site that died in different years (sites 1 and 8s are background); B - the results of the dendroclimatological study; the blue line shows the change in the temperature of the summer period (according to the literature), below it there are lines that correspond to the reconstruction of the temperature from the annual rings of trees at eight sites.
It turned out that the main stage of the mass extinction of trees coincides with the beginning of the development of sulfur-containing nickel deposits and the launch of smelting furnaces (at the turn of the 1960s and 1970s). Around the same time, Arctic trees ceased to be effective indicators of climate change: the chronology of summer temperature changes calculated from the width of their annual rings began to deviate greatly from real meteorological data. In the pre-industrial era and at the beginning of the industrial era, the temperature along the rings was predicted quite well (correlation coefficient r = 0.42, p <0.01) for 1924-1969.
All plots, except for the background, had a large number of dead trees - up to 100 percent in plots three through seven. Scientists have found significant contamination with sulfur, copper and nickel in wood and organic soil. At the fourth site, their maximum concentrations in the soil were found: 2660 ± 188, 828 ± 85 and 716 ± 29 milligrams per kilogram, respectively (according to Federal Law No. 52 "On the Sanitary and Epidemiological Well-Being of the Population", MPCs for them are equal to 160, 3 and 4 milligrams per kilogram). Larch turned out to be more sensitive to pollution due to physiological characteristics: larger than that of spruce, needles surface area, thinner cuticle and higher stomatal conductance.
The authors of the study noted that the results of their study are consistent with the concept of Arctic blackout: oppression and mass death of trees in the vicinity of Norilsk coincided with the period of development of ferrous metallurgy in the region. Probably, the emissions of aerosols, even in quantities that do not lead to a direct increase in the greenhouse effect, had an indirect effect on climate warming through a decrease in the transparency of the lower atmosphere. A decrease in productivity and degradation of forest ecosystems in the north carry a high risk of disrupting the planetary carbon cycle, and it is quite possible that the danger of anthropogenic impact on Arctic vegetation was previously underestimated.
On May 29, more than 20 thousand tons of oil products were spilled into the environment at the Norilsk CHPP-3. In the article "Burn, Drown, Soak or Eat" we talked about how you can eliminate this pollution and what then happens to the affected areas.
Editor’s Note: Following the release, the news was updated with information about the affiliations of the study authors.
