The tundra in Siberia may disappear in less than 500 years

The iconic landscape may no longer exist in 2500.

The Siberian tundra may no longer exist by 2500 if greenhouse gas emissions are not significantly decreased.

According to recent research, scientists have recently predicted that two-thirds of this landscape, characterized by its short growing season and cover of grasses, moss, shrubs, and lichens, could vanish, leaving behind two sections separated by 1,553 miles (2,500 kilometres). And suppose the permafrost cover of the tundra melts away. In that case, it might release significant quantities of greenhouse gases that have been trapped in the atmosphere, which could potentially speed up warming all across the planet.

Stefan Kruse, an ecologist and forest modeller at the Alfred Wegener Institute (AWI) Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany, stated that "this was startling for us to realize how quickly the tundra will be transformed over to the forest." According to Kruse's comments to Live Science, the tundra's disappearance will negatively impact the region's biodiversity and human culture. Still, it may also hasten the warming of the Arctic.

In recent decades, there has been a remarkable acceleration of warming in the Arctic, roughly equivalent to approximately twice the rate of warming seen in the rest of the world. According to the National Snow and Ice Data Center (link opens in a new tab), the average air temperature in the Arctic region experienced an increase of almost 7.2 degrees Fahrenheit (or 4 degrees Celsius) between 1960 and 2019. (NSIDC). This heat has reduced sea ice cover and also affected Arctic land. One of these repercussions is the continued expansion of the larch forests of Siberia into the northern latitudes.

Nobody knows how quickly these forests will take over and replace the grassland and shrubby tundra habitat. According to Kruse, there is no uniform pattern of treeline shifts due to global climate change. In certain instances, the treeline has moved further northward. In some others, their position has not changed, and in still others, they have retreated. Previous research on the Siberian tundra has concentrated on relatively small areas. Yet, there is often a great deal of variation from one spot to the next.

Kruse and his colleague, AWI professor Ulrike Herzschuh, have developed a new computer model that assesses the entirety of the 4,000-kilometre-long (2,485-mile) Siberian tundra. The model takes into account the life cycles of individual trees, including how far they can disperse their seeds, how well they grow when faced with competition from other trees, and growth rates that are based on temperature, precipitation, and the depth of the summer thaw of permafrost that occurs in tundra regions of the world.

Once the trees begin moving northward in reaction to warming, the researchers found that they do so swiftly, and it is unlikely that they will recede again even if temperatures drop. Only 32.7% of the tundra today will still exist in the year 2500 if carbon emissions are brought down to zero by the year 2100. The global temperature rises below 3.6 degrees F (2 degrees C). This portion would be divided into two smaller tundras; one would be located in Chukotka, which is located in the far east, and the other would be located on the Taymyr Peninsula, which is located in the far north.

A cascade of different events

However, even this grim scenario may be impossible to achieve without extremely swift action, which means that the outcome for the tundra may very well be far worse than we now anticipate. An intermediate scenario in which carbon emissions don't start declining until 2050 and are cut by half by 2100 would result in larch trees covering all of the existing tundra by 2500, effectively destroying the ecosystem. In this scenario, carbon emissions will not start declining until 2050 and will be cut by half by 2100.

According to what was published on May 24 in the journal eLife by researchers, warmer global scenarios could result in a northward expansion of trees by as much as 18.6 miles (30 kilometres) when Kruse and Herzschuh found that the treeline did not retreat at the same rate that it had advanced when they investigated what would happen if temperatures cooled after the tundra became a forest. According to Kruse, once mature trees have been established, they can withstand a lot.

According to Kruse, the research did not specifically analyze what might happen to animals that live in tundras, such as reindeer. However, it is generally detrimental for species' survival to split populations into two regions where they are prevented from interbreeding. It is unknown how the extension of forest areas can influence the migration patterns and life cycles of reindeer, which in North America are referred to as caribou. Reindeer move from the north to the south and back throughout the year.

Likely, human beings will also feel the effects. Native communities, such as the Nenets people living in the northwestern part of Siberia, are known to herd and hunt reindeer.

According to Kruse, "the tundra plays an important role in the culture." "If this is lost, it will be a significant setback for the entire human race."
It is also unknown how the disappearance of the tundra may affect future warming. Still, the addition of towering trees to mossy, scrubby grasslands may make the problem even more severe. According to Kruse, the snow-covered tundra is lighter in colour than the larch forest canopy; as a result, the larch forest canopy will absorb more heat than the snow-covered tundra. This might potentially make the Arctic hotter faster. According to the NSIDC, this added heat might speed and intensify the melting of the tundra's permafrost, which stores vast volumes of greenhouse gases (up to 1,400 gigatons globally) (opens in new tab). The thawing of permafrost could release these gases, bacteria, and viruses that have been frozen for an extended period.

According to Kruse, the change will likely go farther than replacing the tundra with larch trees. Evergreen trees can colonize areas that formerly had permafrost because warmer summers thaw deeper and deeper layers of the frozen ground. These trees maintain their leaf cover throughout the year, potentially even better at absorbing heat than larch trees. There is a good chance that the southern half of the taiga, where temperatures are currently higher than in the north, will heat up considerably more, which will lead to drought and wildfires, both of which release even more carbon into the sky.

The findings provide persuasive arguments in support of making significant headway toward reducing emissions from fossil fuels. According to Kruse, the model employed in the study can also be used to identify the parts of the Siberian tundra that are the most robust to climate change. These sites could be given more priority for investments in conservation if they are resilient.

According to him, the most prudent course of action would be to reduce the number of greenhouse gases released into the atmosphere worldwide. However, if we cannot accomplish that, one must engage in species conservation.

 

 

 

Article source : https://www.livescience.com/vanishing-siberian-tundra

Image source  : https://pixabay.com/id/photos/jalan-norway-tundra-lanskap-langit-6576857/

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