(GRE) FOREST FIRES ON THE MOVE

By Matthew William Jones research fellow, University of East Anglia; Crystal A Kolden, assistant professor, University of Idaho; and Stefan H Doerr, director of the Centre for Wildfire Research, Swansea University

Fires have long been a natural part of forest ecosystems, but something is changing. Our new study shows that forest fires have become more widespread and severe amid global heating, particularly in the high northern latitudes such as Canada and Siberia where fires are most sensitive to hotter, drier conditions.

The implications of this are alarming, not just for the ecosystems affected or the cities engulfed by smoke downwind, but for the planet’s ability to store carbon and regulate the climate. The trend we discovered contrasts with declining fire extent in savannah grasslands, which may reflect the expansion of farming and changing rainfall patterns.

We established the leading causes of forest fires in different parts of the world using an AI algorithm. It grouped forest regions into distinct zones with similar fire patterns and underlying causes, uncovering the worrying extent to which climate change is fuelling the expansion of forest fires in Earth’s high northern latitudes.

Since 2001, emissions from fires in forests outside of the tropics, like parts of the boreal forest in the far north of North America and Eurasia, have nearly tripled. This rise is largely the result of hotter, drier weather occurring more frequently, combined with forests growing more efficiently in places where the cold once stunted their growth.

Climate change is creating ideal conditions for larger, more intense fires, which accelerate climate change in turn by releasing more carbon to the atmosphere. In fact, we found that global carbon emissions from forest fires have increased by 60% over the past two decades. The largest contributions come from fires in Siberia and western North America.

This trend shifts the focus of forest fire emissions from tropical forests, where fires set to make room for farmland have long contributed carbon to the atmosphere. Conservation policies have reduced deforestation rates since the early 2000s in some regions, particularly Amazonia. By contrast, increasing fires in northern forests, such as the taiga – the forest of the cold sub-arctic region – are driven by changing climate conditions and generally started by lightning, which makes them harder to prevent. More of this article (green queen) - link - more like this (forest fires) - link - more like this (Canada) - link