As a result of global warming, temperatures in the Arctic are fast rising. As a result, the treeline for Siberian larch forests is continuously moving north, eventually displacing large swaths of tundra that are home to a diverse range of plants and species. The Alfred Wegener Institute has created a computer simulation of how these woodlands might grow in the future at the expense of the tundra. Only persistent climate protection efforts, they conclude, will allow around 30% of the Siberian tundra to live until the middle of the millennium. In all other, less fortunate situations, the one-of-a-kind environment is expected to vanish completely.
The Arctic is severely affected by the climate crisis: average air temperatures in the High North have risen by more than two degrees Celsius (3.6 degrees Fahrenheit) in the last 50 years, significantly more than anyplace else. And this is only going to get worse. Further warming of the Arctic until the end of the century might be reduced to slightly under two degrees if substantial greenhouse-gas reduction efforts (Emissions Scenario RCP 2.6) are implemented. According to model-based projections, if emissions continue high (Scenario RCP 8.5), average summer temperatures in the Arctic might climb by up to 14 degrees Celsius (25 degrees Fahrenheit) by 2100, compared to today's standard.
“For the Arctic Ocean and the sea ice, the current and future warming will have serious consequences,” says Prof Ulrike Herzschuh, Head of the Polar Terrestrial Environmental Systems Division at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). “But the environment on land will also change drastically. The broad expanses of tundra in Siberia and North America will be massively reduced, as the treeline, which is already slowly changing, rapidly advances northward in the near future. In the worst-case scenario, there will be virtually no tundra left by the middle of the millennium. In the course of our study, we simulated this process for the tundra in northeast Russia. The central question that concerned us was: which emissions path does humanity have to follow in order to preserve the tundra as a refuge for flora and fauna, as well its role for the cultures of indigenous peoples and their traditional ties to the environment?”
The tundra is home to a unique population of plants, around 5% of which are endemic to the Arctic, meaning they can only be found there. Mountain avens, Arctic poppy, and prostrate plants like willows and birches are examples of typical species that have adapted to the severe local circumstances of short summers and long, difficult winters. Rare animals like reindeer, lemmings, and insects like the Arctic bumblebee call it home.
Ulrike Herzschuh and AWI modeller Dr Stefan Kruse used the AWI vegetation model LAVESI in their simulation. “What sets LAVESI apart is that it allows us to display the entire treeline at the level of individual trees,” Kruse adds. “The model portrays the entire lifecycle of Siberian larches in the transition zone to the tundra – from seed production and distribution, to germination, to fully grown trees. In this way, we can very realistically depict the advancing treeline in a warming climate.”
The results speak for themselves: larch forests might move northward at a rate of up to 30 kilometers (19 miles) every decade, according to the researchers. The tundra expanses, which are unable to relocate to colder places owing to the proximity of the Arctic Ocean, will decrease. Because trees aren't mobile, and each tree's seeds have a certain dispersion radius, the vegetation would first trail behind the warming, but eventually catch up. In the majority of scenarios, by the middle of the millennium, fewer than 6% of today's tundra would survive; conserving around 30% would need aggressive greenhouse-gas mitigation initiatives.Otherwise, Siberia's once-unbroken 4,000-kilometer (2,500-mile) tundra belt would be reduced to two areas, separated by 2,500 kilometers (1,600 miles), on the Taimyr Peninsula to the west and the Chukotka Peninsula to the east. Even if the atmosphere chilled again throughout the millennia, the woods would not be able to totally release the old arctic lands.
“At this point, it’s a matter of life and death for the Siberian tundra,” says Eva Klebelsberg, WWF Germany's Project Manager Protected Areas and Climate Change/Russian Arctic. “Larger areas can only be saved with very ambitious climate protection targets. And even then, in the best case, there will ultimately be two discrete refuges, with smaller flora and fauna populations that are highly vulnerable to disrupting influences. That’s why it’s important that we intensify and expand protective measures and protected areas in these regions, so as to preserve refuges for the tundra’s unparalleled biodiversity,” adds Klebelsberg, who is a proponent of protected areas in partnership with the Alfred Wegener Institute.
“After all, one thing is clear: if we continue with business as usual, this ecosystem will gradually disappear.”
Reviewed by Lilit
on
May 31, 2022
Rating:
.png)
