4. "Zombie fires" show warming's toll — and worsen it
"Zombie fires" may sound like science fiction, but they're a real phenomenon likely to grow more common near the Arctic — and maybe within it — as climate change continues, a new study finds.
Why it matters: The study in Nature provides conclusive evidence that zombie or "holdover fires" exist and can be monitored. And helps to begin quantifying their impact on climate change.
How it works: Zombie fires are blazes that ignite and burn in one season, then smolder through the winter within peat and other soils, emitting smoke but little or no flames. Then they reemerge during the next spring, erupting into flames again.
- Numerous zombie fires were reported in Siberia last summer and were anecdotally reported during the summer of 2019 too, University of Colorado soils and wildfire expert Merritt Turetsky tells Axios.
- Peat is damp soil that contains decaying plant material and releases large amounts of global warming pollutants when burned.
What they're saying: Turetsky, who was not involved in the study, calls zombie fires a "legacy" in the climate, where one fire season can return to "haunt" the next.
"It's like a ghost of last year's fire season continuing to pop up and influence the contemporary season," she said.
By the numbers: Between 2002 and 2018, zombie fires caused about 1% of the total burned area in the regions studied in Canada's Northwest Territories and Alaska.
But there's lots of variation — in some years, such blazes accounted for nearly 40% of the total burned area, the paper finds.
Threat level: Carbon emissions from zombie fires comprise a relatively small amount (0.5%) of total CO2 emissions from fires in the regions surveyed.
"Yet this fraction may grow larger with climate warming," the study states.