Southeast Asia is accustomed to intense smoke and haze from forest burning, but in June 2013 air pollution reached the highest level ever recorded -- hitting life-threatening levels in Singapore, for instance. This alone was scary enough, but there is an even more frightening side to the story.
Unlike virtually all previous mega-fire events in the region, the June 2013 fires didn't occur during a drought. That is unprecedented.
Even in a year with normal rains, fires -- especially in central Sumatra, where forests are being devastated for oil palm, pulpwood plantations, and slash-and-burn farming -- raged out of control.
New research by David Gaveau and colleagues -- which you can download free here -- has uncovered an alarming explanation for this new fire dynamic.
Previous degradation and burning of forests is making them hyper-vulnerable to new fires, even during relatively wet conditions.
Gaveau surveyed the aftermath of the Sumatra burning and found that much of it was caused by slash-and-burn farmers. And most of the burned land was degraded forest or peat-swamp that had already been burned once before.
The previous burning left behind dead and dying trees, stumps, and slash that became highly flammable with just a few days of dry weather -- unlike an intact rainforest, which only becomes flammable after a prolonged and intense drought.
Gaveau calls these degraded areas "forest cemeteries" -- places where damaged, regenerating forests become prone to a final, fiery death -- and spewing out massive quantities of greenhouse gases in the process.
Central Sumatra has become a poster-child for forest devastation, and now this new research shows that its damaged forests are far more prone to killer fires -- fires that can also have a lethal impact on human populations living in the region.