The name “Indonesia” doesn’t mean “land of fire” — it just seems that way. Biomass burning related to land-clearing for agriculture goes on practically all year, particularly in summer and fall. Fires tend to burn continuously for months because of the peaty soil. In drought years the impact can be especially devastating. A “haze disaster” caused by fires in 1997-98 led to the deaths of hundreds of people and caused respiratory illness in tens of thousands more.
But a study in Nature Geoscience suggests that while drought may lead to the worst incidences of burning, land use and population density also play roles.
Fire-monitoring data from satellites is not available from before the mid-1990s, so Robert D. Field of the University of Toronto and colleagues instead used visibility records from airports from 1960 to 2006. As expected, they found that severe burning events happened in years when rainfall was below a certain level.
But they also found a difference in the fire record between the island of Sumatra and Kalimantan, the Indonesian portion of Borneo. Severe fire events have happened since the 1960s (and possibly before) in Sumatra, but only since the 1980s in Kalimantan, even though they experienced the same droughts.
The researchers point out that Sumatra historically had much higher population densities than Kalimantan, and that population growth accelerated in Sumatra in the 1960s and ’70s. Growth did not take off in Kalimantan until the 1980s. Coupled with government policies that endorsed a shift from small-scale farming to large-scale agribusiness, the changes in Kalimantan made the fire situation worse in recent decades.
Source: The New York Times