In the far north of the planet, a vast expanse of forests ring the Arctic Ocean like a halo, stretching across Russia, Canada, Scandinavia and even parts of Scotland. The boreal forest is the world’s largest biome, containing a third of all trees. Yet the treeline – the latitude above which it’s too cold for trees to grow – is expanding rapidly northwards as temperatures rise, turning once solidly white landscapes green.
Rising temperatures could see the southern boundary of the forests shift north by as much as 1,000 kilometres by the end of the century, turning vast swathes of inhospitable regions such as Siberia into fertile agricultural land. While this may sound appealing, it’s wreaking havoc on delicate ecosystems and the people and animals that rely on them. ‘The migration of the treeline north is no longer a matter of centimetres per century; instead it is hundreds of metres every year,’ writes Ben Rawlence in The Treeline.
Rawlence offers a sobering account. Six hardy species – Scots pine, larch, spruce, poplar and rowan – make up the bulk of the boreal forest, each playing a key role in a specific geography; more than a third of the Russian taiga, considered the greatest forest in the world, is made up of larch. Rawlence, whose previous books City of Thorns and Radio Congo chronicle refugee camps and war-torn Africa, uses the trees as a starting point to explore the changing north of the planet, travelling from Scotland to Canada and Greenland, via Norway and Russia, to spend time with scientists and those whose lives are being most affected by the changing landscape.
The Treeline is a powerful reminder of the far-off impacts of global warming. Sámi reindeer herders in Norway are finding their way of life threatened, with the increase in tree numbers leading to snow drifts too deep for reindeer to dig through to reach vital nutrients. In 2013, and again in 2017, thousands of reindeer died of starvation. In 2019, forest fires in Siberia saw an area larger than Austria burn. Increasingly, indigenous people are giving up their traditional ways of life – early victims of climate change. It’s a trend that will likely only continue, as climate change alters the world around us in ways we can’t fathom, or choose not to dwell on. As Rawlence writes, trees no longer offer comfort, but instead a warning for the future.