Vegetation impacts energy movement in the Arctic

Since 1979, the Arctic has warmed four times faster than the rest of the globe due to climate change. Increases in temperature have reduced the extent of sea, snow cover, and permafrost altered plant communities in the region. Such changes can have a significant impact on how energy moves between the land and the atmosphere, subsequently affecting weather and temperature patterns around the world.

By analyzing the impacts of various drivers on energy exchange – the process by which energy moves between the land and the atmosphere in the Arctic – a team of researchers from 63 institutions discovered that vegetation type, which is largely ignored in climate models, is in fact a primary predictor of how energy is exchanged during the Arctic summer.

“I expected there to be differences in vegetation type, but not to this extent,” said study co-author Ryan Sullivan, an assistant atmospheric scientist at the Argonne National Laboratory. ​“Vegetation type had stronger predictive skill on the surface energy budget than permafrost, temperature, snow cover, and cloud cover. We hope that people improve treatment of vegetation type in Earth system models and use this to also better understand how these effects might change in the future.”

The surface energy budget is a measure of how much energy from the sun reaches the Earth’s surface and is rather absorbed or reflected back to the atmosphere. It includes four main components: net radiation (the amount of energy that goes into Earth’s system), sensible heat flux (energy that is transferred as heat and causes changes in temperature), latent heat flux (a change in energy that does not result into a change in temperature), and ground heat flux (energy stored in the ground).

By evaluating the effects of 15 drivers on these four components of surface energy budget in the Arctic from June to August – with data collected between 1994 and 2021 at 64 measuring stations – the scientists found that the type of vegetation community was a better predictor of sensible and latent heal flux, despite the fact that snow and ice play a major role in reflecting heat back into the atmosphere.

​“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,” said study lead author Jacqueline Oehri, a postdoctoral fellow in Global Change and Biodiversity at McGill University.

According to the researchers, this happens because the Arctic exhibits extensive diversity in plant communities, with plants differing in height, productivity, and albedo traits and thus significantly impacting how energy moves between the land and the atmosphere.

“We hope that people improve treatment of vegetation type in Earth system models and use this to also better understand how these effects might change in the future,” Sullivan concluded.

The study is published in the journal Nature.

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By Andrei Ionescu, Earth.com Staff Writer

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