The tundra has been considered an important carbon sink, acting as a sink that stores large amounts of carbon in its frozen soil. However, the effects of the climate change are profoundly altering this function. The progressive increase in temperatures is causing the release of this carbon in the form of carbon dioxide (CO2) y methane into the atmosphere, exacerbating global warming.
Tundra ecosystems, located in Arctic regions such as Greenland, Siberia and Alaska, are particularly sensitive to changes in climate. For more than a decade, researchers at Zackenberg Station in northern Greenland have been monitoring the carbon balance in the tundra. northern hemisphere tundra, revealing how organisms that inhabit these regions are changing their role as carbon storers to net emitters.
In a recent study, published in the Journal of Geophysical Research, it is evident that the carbon dioxide emission by living organisms is increasing as temperatures rise. Also, the process of photosynthesis, which is key to capturing CO2, is also negatively affected. There are critical temperatures, such as 7ºC, which, once exceeded, carbon storage in these ecosystems practically ceases.
Impact of climate change on the tundra carbon cycle
The carbon cycle in the tundra is directly influenced by temperatures. As the climate warms, the top layer of permafrost thaws, which in turn allows microorganisms to decompose the carbon. organic material previously frozen. This process results in the release of large amounts of CO2 and methane, greenhouse gases that increase the impact of climate change.
Various studies, such as the one led by the NASA In the Arctic, they show that the tundra is evolving towards more aquaculture-like behavior. boreal forests, ecosystems found in areas of lower latitude. This phenomenon includes the migration of plant species such as shrubs and small trees to the north, which also affects the carbon cycle.
Satellite observations, using advanced technology such as the ICEat-2 y Landsat, have made it possible to document these changes in the carbon cycle and the shift of vegetation towards the Arctic. With more shrub vegetation, the tundra could absorb some CO2, but thawing permafrost remains a critical threat, as emissions of ancient carbon will offset any additional absorption by vegetation.
Early defrosting and its consequences
One of the biggest challenges facing the tundra is the early defrost associated with climate change. A group of researchers has pointed out that the earlier spring, which occurs due to milder winters, alters the life cycle of vegetation in the tundra. This change could reduce the ability of the tundra to act as a carbon sink.
The normal cycle of the tundra ensures that decomposing plants slowly release carbon over the long winters, allowing the soil to store it. However, early snowmelt creates an imbalance in this cycle, facilitating the release of CO2 before plants can absorb significant amounts through photosynthesis. The result is a net contribution to the increase in greenhouse gases.
Arctic warming and tundra retreat
Among the most striking effects of Arctic warming is the tundra retreat. According to recent research, if climate change measures are not rigorously implemented, it is estimated that by the middle of this millennium, only 6% of the current tundra will remain in northeastern Russia. This process is due to the expansion of tree species such as the Siberian larch, which are advancing north at a rate of 30 kilometers per decade, displacing the characteristic plants of the tundra.
This change not only has an impact on Arctic flora and fauna, but also affects the already weakened capacity of the tundra to store carbon, accelerating global climate change. Warmer temperatures allow for greater decomposition of organic matter, which in turn releases even more carbon from the permafrost.
The tundra as a carbon sink in danger
Historically, the tundra has been considered a carbon sink efficient due to the low temperatures that limit the decomposition of organic matter. However, the effects of global warming are making this role of sink compromised. As the permafrost As the sea level melts, vast amounts of carbon stored for centuries begin to be released, potentially turning the tundra into a net source of carbon rather than a sink.
Scientific studies continue to debate whether these Arctic ecosystems will be able to continue fulfilling their role as carbon sinks under current climate conditions, but what is clear is that the increase in temperature and the thawing of the soil do not bode well for the carbon storage capacity of the tundra. This situation has led the scientific community to make urgent calls for the protection of these ecosystems, implementing drastic measures to mitigate climate change.
Recent studies continue to show that the tundra, a fragile ecosystem, is undergoing a transformation that could alter its primary function as a carbon sink. Without adequate measures, accelerated permafrost thawing will continue to release large amounts of greenhouse gases, further contributing to global warming.