Arctic zombie wildfires intensify global warming

Massive wildfires have in recent years blazed even in the Arctic regions where peatland fires can smolder under the snowpack during winter and reignite in early spring along with the rising surface temperature. The phenomenon is named ‘Arctic zombie wildfires’ by scientists. The fires intensify global warming and have serious consequences in terms of local ecosystems and human health.

Published 7.9.2023
Text: Masoud Irannezhad
Image: Shutterstock
Editing: Viestintätoimisto Jokiranta Oy


Arctic wildfires may sound odd as a concept, but the phenomenon is real and, in recent years, alarmingly more frequent. Named as ‘Arctic zombie wildfires’ by scientists, this phenomenon will lead to serious problems if it becomes a new normal. In addition to changing the ecological systems within their scorched area, such wildfires also intensify global warming by releasing carbon from the peat and influence human health by emitting particulates to the Earth’s atmosphere. My research aims at a better understanding of such Arctic zombie wildfires by assessing their climatic and environmental drivers.   


Snow drought turns peatlands into a tinderbox

More frequent Arctic zombie wildfires have highlighted the cascading environmental effects of compound climate extreme events in the Arctic regions. Compound climate extreme events refer to coinciding, multiple, interdependent natural hazards, such as extreme droughts and persistent heatwaves. Accordingly, snow drought as a natural hazard in boreal environments has become a new growing research interest.

In cold regions, decreases in the number of cold days during winter may result in more rainfall and/or less snowfall and thereby reduce snowpack accumulation on the ground. The reduced amounts of snow may decline refreezing of liquid water inside the snowpack by decreasing its maximum retention capacity. At the same time, a warmer climate will amplify the rate of snowmelt.

All these changes lead to decreases in snow water equivalent (SWE), a reduction in spring melt volume, and earlier snowmelt runoff. In response, more frequent winter floods, a decline in spring groundwater level and less summer base flow as well as an increased risk of drought and dry peatlands are expected. Hence, snow drought in boreal environments plays a crucial role in triggering zombie wildfires by turning an abnormally wide area of Arctic peatlands into a tinderbox.


SnowDrop lays the foundation for future research of Artic zombie wildfires

The aim of my current research project, SnowDrop, is to develop innovative approaches for: (1) revisiting the snow drought (SD) concept; (2) identifying Fenno-Scandinavian SD hotspots based on their intensity, frequency, duration, and extent; (3) determining SD development phases (growth, persistence, and retreat); (4) investigating climate factors driving Fenno-Scandinavian SD hotspots; (5) analyzing historical and future changes in quantity and quality of Fenno-Scandinavian major snow-dependent rivers in response to SD; and (6) investigating hydrological responses of peatlands in Finland, Sweden, and Norway to such SDs.

The findings by SnowDrop will lay the foundation for developing nature-based solutions as well as adaptation and mitigating strategies for sustainably coping with future wildfires in the cold environment of the Fenno-Scandinavian region.


Masoud Irannezhad.


Dr. Masoud Irannezhad is working as a Senior Research Fellow at the University of Oulu and an Assistant Professor of Civil Engineering at the Australian University in Kuwait. In 2015, he received his Ph.D. in Environmental Engineering (Water Resources) from the University of Oulu. He was a Research Associate at the Portland State University (USA) in 2016–2017 and a Research Assistant Professor at the Southern University of Science and Technology (China) in 2018–2020.

Dr. Irannezhad is a contributing author to the IPCC 2022 report as well as a Young Career Researcher Editorial Board Member of the Hydrology Research journal. His research focuses on atmosphere, climate and water interactions. He has published 42 peer-reviewed journal papers, which have been cited 838 times. Based on his publication in Science, Dr. Irannezhad is currently doing research on different climate drivers, hydrological implications, and environmental sustainability risks of future snow droughts in Fenno-Scandinavia.






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