The vast boreal forests of the Northern Hemisphere stretch from Scandinavia through Siberia, Alaska and Canada. They cover a tenth of the world’s land but hold one-third of the land’s carbon, stored mainly in organic-rich soils and in trees. Now, a new study in the journal Science provides further evidence that emissions from wildfires in high northern latitudes are already increasing at an alarming rate.
In these forests, the cold climate and often waterlogged ground means fallen tree bark, needles and other dead organic matter takes a long time to decompose. This has allowed the soils to accumulate carbon over thousands of years after the ice sheets retreated at the end of the last ice age. Since then, these ecosystems have mainly been shaped by wildfires ignited by lightning.
