Reindeer might play an integral role in slowing down climate change

A new study found that reindeer might play an integral part in slowing down climate change. Published in the journal Environmental Research Letters, Dr. Mariska te Beest of Umeå University and her team of researchers found that through grazing, reindeer increase the amount of solar energy reflected by the earth back into space.

In this article, the researchers refer to this reflection of solar energy by the earth as “surface albedo.” When reindeer graze, and thus reduce the height and abundance of shrubs on the Artic tundra, they increase the surface albedo. Dr. te Beest explains: “Our theory was that heavy grazing by reindeer increases summer albedo through a reduction in shrub height, abundance, and leaf area index.”

Their study combined land surface computer modeling with actual measurements of surface albedo and vegetation characteristics taken in the field. The field measurements were done in a region of Norway that contained four topographically-defined vegetation types, which varied in shrub height and abundance.

The team worked during the summer season, estimating reindeer activity by using vegetation-trampling indicators and collecting dung. They made field measurements of the abundance of vegetation, the leaf area index, as well as soil moisture and temperature levels. Researchers also measured surface albedo levels in the studied areas.

Dr. te Beest and her team found that through decreasing shrub abundance, high densities of reindeer can completely change Artic tundra vegetation. These changes in abundance, canopy height, and amount of live vegetation led to a substantial increase in surface albedo throughout the growing season.

By using computer modeling, the researchers were able to determine that this increase in albedo would result in a decrease in net radiation, as well as latent and sensible heat fluxes. This indicates that heavily grazed sites are actually absorbing less radiation.

Dr. te Beest believes their findings can have a significant impact on the climate warming conversation, saying “Our results show that reindeer have a potential cooling effect on climate, by changing the summer albedo. Although the estimated differences might appear small, they are large enough to have consequences for the regional energy balance.”

Given that most of the Artic tundra is grazed by either wild or domesticated reindeer, this finding could be very important.

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Credit: Earth.com author Connor Ertz