Vegetation in the Arctic controls the temperature on the surface, according to a study published in Nature Communications. The authors defend that this information needs to be included in climate change models, allowing researchers to get a better picture of temperature changes in this area.
How does the vegetation in the Arctic affect temperature? This is a valid question, given how the region can influence climate change. The reality is that this area is warming up at about twice the rate of the global average, which is causing the permafrost to melt. This effect is being felt far away from the Arctic, for example, in the cold damage in ecosystems in East Asia.
An international team led by researchers from the Department of Evolutionary Biology and Environmental Studies of the University of Zurich (UZH) decided to analyse how temperatures changes in the Arctic.
According to their results, the Arctic’s vegetation — which is often ignored in climate models — is a crucial factor in controlling the temperature on the surface. “Remarkably, in summer, the difference in heat flux between two types of vegetation – such as a landscape dominated by lichens and mosses and one with shrubs – is about the same as between the surface of glaciers and green grasslands,” says postdoc Jacqueline Oehri, first author of the study.
This vegetation is highly diverse, including dry grasslands and wetlands, as well as dwarf shrubs and areas covered with mosses and lichens. The team collected temperature data from 64 measuring stations in the Arctic between 1994 and 2021 and tried to establish a relationship with the vegetation present in the area. They focused on the summer months between June and August when sunlight is particularly high.
Depending on the vegetation present, either the surface or the air can warm up to varying degrees. Shrubs, for example, can warm up the surface earlier after the winter. “The shrubs’ dark branches emerge from under the snow early, absorb sunlight and pass it on to the surface long before the snow melts away,” explains Oehri.
The authors believe this knowledge is important because it has an effect on the permafrost. “Our findings on the energy flows in the Arctic are extremely relevant since the preservation of permafrost depends to a large extent on the heat flux into the ground,” says UZH professor Gabriela Schaepman-Strub.
The study makes it possible to add the effects of different plants into climate predictions. Researchers can then use these improved climate models to calculate weather and assess how Arctic vegetation plays a role in the cooling of the land surface. “We now know which plant communities have a particularly pronounced cooling or warming effect through energy exchange. This enables us to determine how changes in plant communities, which are occurring in many regions in the Arctic, are affecting permafrost and the climate,” says Schaepman-Strub.
The researchers warn that this needs better data collection. The Arctic may be very important when it comes to climate change, but there are only a few reliable measuring stations in this region.
Oehri, J., Schaepman-Strub, G., Kim, JS. et al. Vegetation type is an important predictor of the arctic summer land surface energy budget. Nat Commun 13, 6379 (2022). https://doi.org/10.1038/s41467-022-34049-3