A new international study warns that reindeer — known as caribou in North America — could experience population declines unmatched in 21,000 years, with North American herds at risk of shrinking by up to 80% by 2100 if greenhouse gas emissions continue unchecked.
Published in Science Advances, researchers from the University of Adelaide, the University of Copenhagen, and other institutions conducted the study. It combines fossil evidence, ancient DNA, and computer modelling. These methods are used to track reindeer abundance and distribution over millennia and to forecast their future.
Ice Age Survivors Facing Unprecedented Threats
Reindeer are Ice Age survivors, uniquely adapted to Arctic environments. They play a vital role in tundra ecosystems, regulating plant diversity and supporting the livelihoods of many Indigenous Peoples.
But over the last three decades, climate change has already caused a two-thirds drop in their global abundance.
“Populations of reindeer have experienced significant declines during past periods of rapid climate warming. However, the losses expected in the coming decades are likely to be even more severe,” said lead investigator Dr. Elisabetta Canteri, University of Adelaide and University of Copenhagen.
North America’s Caribou Most at Risk
The modelling reveals North American caribou are the most vulnerable to warming Arctic temperatures, with declines of up to 80% by 2100 unless:
- Greenhouse gas emissions are drastically reduced
- Wildlife management and conservation efforts are significantly increased
Associate Professor Damien Fordham, co-lead author, warns that these losses will have far-reaching ecological consequences, making both North American caribou and Eurasian reindeer more vulnerable to climate stress.
Ecological and Climate Feedback Loops
Reindeer grazing helps maintain plant diversity in the tundra. Without them:
- Plant diversity declines
- Carbon storage in Arctic soils is reduced
- More soil carbon is released into the atmosphere, worsening climate change
“The loss of reindeer and caribou could further accelerate Arctic warming — threatening not only these species but also human communities,”
said Professor Eric Post of UC Davis.
Call for Urgent Action
The study concludes that investing in reindeer and caribou conservation — especially in North America — will protect biodiversity, safeguard Indigenous food security, and help maintain the ecological balance of Arctic landscapes.
“For thousands of years, humans have benefitted from healthy reindeer and caribou populations. Now, more than ever, we must ensure their survival,”
said Fordham.
