Climate, Siberian tundra at risk: it could disappear by 2500

Every day the scientific community raises an alarm linked to climate changes that put ecosystems and natural resources at risk. After examining the effects on the Alps – ever greener and less icy – now it’s up to Siberian tundra, also at risk. In less than 500 years, without a change of course, about 2/3 of the tundra could disappear, replaced by a forest, and divide into two zones 2,500 kilometers apart.

It was amazing to see how quickly the tundra will be transformed into a forestcommented ecologist Stefan Kruse of the Helmholtz Center for Polar and Marine Research at the Alfred Wegener Institute (AWI) in Bremerhaven, Germany. Even more serious, it is wrong to think that the damage will be limited to that geographical area: the melting of the permafrost of the Siberian tundra will in fact release large quantities of the greenhouse gases stored in it into the atmosphere that could accelerate the process of global warming.

TUNDRA AT RISK DISAPPEARANCE EVEN WITH REDUCED EMISSIONS



Stefan Kruse and Ulrike Herzsch (his colleague at AWII) have created a new computer model which takes into account the entire expanse of the Siberian tundra, namely an area of ​​4,000 kilometers, and in particular all parameters relating to the life cycles of larch trees (how far they can spread their seeds, how fast they grow compared to other trees, the rate of growth based on temperature, rainfall and the depth of permafrost thaw that occurs in the summer period).

The model made it possible to highlight that:

  • as temperatures rise, larch trees tend to grow rapidly towards the north, and a decrease in temperatures is unlikely to lead to a reversal of the trend.
  • in the best scenario, assuming that carbon emissions are eliminated by 2100 and that the increase in global temperature remains below 2 degrees, by 2500 the current tundra would only remain 32.7%. This percentage would in turn become divided into two “mini tundras” one in the far east in Chukotka and the other in the north on the Taymyr peninsula.
  • in the worst case scenario, with a reduction in emissions that will not occur before 2050 and with emissions reduced by 50% by 2100, in 2500 the larch forest would cover all the current tundra excluding an area equal to 5.7% of the total. This would amount to total annihilation.

CHAIN ​​REACTION

The study does not consider what theimpact on the ecosystem of the tundra, even in the best scenario. However, assuming a natural habitat split in two could jeopardize the survival of animal species – for example, reindeer migrate throughout the year from the north to the south of the tundra and it is not possible to predict how the expansion of forests could affect their habits. .

You don’t even know how this is process could affect global warmingbut it should not be overlooked that the larches will absorb more heat than the moss and bushes that form the tundra, and that this could make the Arctic increasingly hot and accelerate the melting process of the permafrost within which they hide. about 1,400 gigatonnes of greenhouse gases which, as mentioned at the beginning, could contribute to the increase in world temperatures.

Scientists then warn about the future extension of green areas in the tundra that will not be limited to larch trees: the deeper the melting of the permafrost, the more the evergreen trees will find the ideal climatic conditions to grow. The alternatives on the horizon to ensure that the scenarios envisaged by the model do not occur are few:

The best option would be to reduce global greenhouse gas emissions to reduce the pressure. But still, if we can’t do it, we need to preserve the species.


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