One of the most disastrous results of climate change is the initialization of feedback loops which themselves further the impact of climate change. One of the most potentially dangerous of these are the fires which burn through the dryer parts of our planet. And according to a new study published in the journal Nature Geoscience this week, the increase in the number and ferocity of fires are pumping more carbon dioxide into the atmosphere than was previously understood.
Researchers visited almost 200 forest and peatland sites shortly after large fires were extinguished to gauge just how much was burnt. The study revealed that fires in the Alaskan interior have become more severe over the past 10 years and, as a result, have released more carbon into the atmosphere than was stored by the region’s forest over the same period.
“When most people think of wildfires, they think about trees burning, but most of what fuels a boreal fire is plant litter, moss and organic matter in surface soils,” said University of Guelph professor Merritt Turetsky, lead author of the study.
“These findings are worrisome because about half the world’s soil carbon is locked in northern permafrost and peatland soils. This is carbon that has accumulated in ecosystems a little bit at a time for thousands of years, but is being released very rapidly through increased burning.”
“Essentially this could represent a runaway climate change scenario in which warming is leading to larger and more intense fires, releasing more greenhouse gases and resulting in more warming. This cycle can be broken for a number of reasons, but likely not without dramatic changes to the boreal forest as we currently know it.”
US Geological Survey scientist and study co-author Jennifer Harden notes that this study is yet more evidence that northern ecosystems are bearing the brunt of climate change. “This includes longer snow-free seasons, changes in vegetation, loss of ice and permafrost, and now fire, which is shifting these systems from a global carbon sink toward a carbon source.”
“Over the past 10 years, burned area has doubled in interior Alaska, mostly because of increased burning late in the fire season,” said co-author Eric Kasischke, a University of Maryland professor. “This is the first study that has demonstrated that increases in burned area are clearly linked to increases in fire severity. This not only impacts carbon storage, but also will accelerate permafrost loss and changes in forest cover.”