Residents of Indonesia and Singapore have been bracing themselves in recent weeks as WRI and others have warned that this year’s dry season would likely herald a severe spike in fires on the island of Sumatra and accompanying toxic haze across the region. As dry weather sets in, with a high chance of a fire-fanning El Nino, NASA’s Active Fires satellite system has detected an alarming numbers of hotspots in recent days, especially in Riau Province, the location of the majority of fires in severe fire and haze episodes last June and early this year.
As described in WRI’s previous analyses, fires are a long-standing problem in many parts of Indonesia. The fires, which are often used to clear land for agriculture, generate toxic air pollution and can easily get out of control. Although the causes of these fires are complex, they are often attributed to companies clearing land for oil palm or other plantations, small farmers clearing land for cultivation, or communities which may use fire as a weapon in conflicts with companies or the government.
Fires concentrated in Bengkalis, Rokan Hilir and Pelalawan districts
Figures 1, 2, and 3 below show the districts and subdistricts in Riau with largest numbers of high-confidence fire alerts over the past week. As in February this year and June last year, fire alerts are overwhelmingly concentrated in the districts of Bengkalis, Rokan Hilir and Pelalawan.
Many fires are in concessions
Figures 4 and 5 below show which pulpwood, palm oil, and logging company concessions also show the largest numbers of high-confidence fire alerts within their boundaries. Many of these have also seen high numbers of fire alerts in the past.
The good news is that policymakers in Indonesia have started to heed earlier warnings about the fire risk. Indonesia’s Vice President Boediono has convened senior ministers from several agencies and a special “situation room” is reportedly being established to help ensure a more coordinated response. Such efforts should now be redoubled to ensure fire-fighting capabilities are on hand to respond within hours when new hotspots are detected. Fires left unattended will otherwise quickly spread, making fire-fighting extremely costly, largely ineffective and dangerous.
As WRI has stressed in the past, the key step needed is to take interagency coordination and resource commitment a step further and work to address the underlying causes of the fires, while also greatly enhancing enforcement efforts, which have been severely under resourced. WRI’s recommendations are summarized in early analyses here.
LEARN MORE: For more WRI analysis on Indonesia’s fires, check out our blog series.
WRI used NASA’s Active Fire Data to determine the likely location of fires on the ground. This system uses the NASA MODIS satellites that survey the entire earth every 1-2 days. The sensors on these satellites detect the heat signatures of fires within the infrared spectral band. When the satellite imagery is processed, an algorithm searches for fire-like signatures. When a fire is detected, the system indicates the 1 km2 where the fire occurred with an “alert.” The system will nearly always detect fires of 1,000 m2 in size, but under ideal conditions, can detect flaming fires as small as 50 m2. Since each satellite passes over the equator twice a day, these alerts can be provided in near-real time. Fire alerts are posted on the NASA FIRMS website within 3 hours of detection by the satellite.
The accuracy of fire detection has improved greatly since fire detection systems were first developed for the MODIS satellites. Today, the rate of false positives is 1/10 to 1/1000 what it was under earlier systems first developed in the early 2000s. The algorithm used to detect fires includes steps to eliminate sources of false positives from sun glint, water glint, hot desert environments and others. When the system does not have enough information to detect a fire conclusively, the fire alert is discarded. In general, night observations have higher accuracy than daytime observations. Desert ecosystems have the highest rate of false positives. Many papers have been published to validate the NASA MODIS active fire alerts for use in various applications. WRI is employing a recommendation for detecting forest clearing fires (described in Morton and Defries, 2008), identifying fires with a Brightness value ≥330 Kelvin and a Confidence value ≥ 30% to indicate fires that have a high confidence for being forest-clearing fires. Low confidence fires are lower intensity fires that could either be from non-forest-clearing fire activity (clearing fields or grass burning), or could be older fires that have decreased in intensity (smoldering rather than flaming fires). The use of this classification establishes a higher standard for fire detection than using all fire alerts equally.
NASA FIRMS FAQ Morton, D., R. DeFries, J. T. Randerson, L. Giglio, W. Schroeder, and G. van der Werf. 2008. Agricultural intensification increases deforestation fire activity in Amazonia. Global Change Biology 14:2262-2276.
Data Sources for Figures:
NASA Fire Information for Resource Management (FIRMS) Active Fire Data, June 17, 2014 – June 23, 2014
Administrative boundaries from GADM and Center for International Forestry Research (CIFOR)
This post originally appeared on WRI Insights