Major atmospheric emissions from peat fires in Southeast Asia during non-drought years: evidence from the 2013 Sumatran fires

Abstract

Trans-boundary haze events in Southeast Asia are associated with large forest and peatland fires in Indonesia. These episodes of extreme air pollution usually occur during drought years induced by climate anomalies from the Pacific (El Niño Southern Oscillation) and Indian Oceans (Indian Ocean Dipole). However, in June 2013 – a non-drought year – Singapore's 24-hr Pollutants Standards Index reached an all-time record 246 (rated “very unhealthy”). Here, we show using remote sensing, rainfall records and other data, that the Indonesian fires behind the 2013 haze followed a two-month dry spell in a wetter-than-average year. These fires were short-lived (one week) and limited to a localized area in Central Sumatra (1.6% of Indonesia): burning an estimated 163,336 ha, including 137,044 ha (84%) on peat. Most burning was confined to deforested lands (82%; 133,216 ha). The greenhouse gas (GHG) emissions during this brief, localized event were considerable: 172 ± 59 Tg CO2-eq (or 31 ± 12 Tg C), representing 5–10% of Indonesia's mean annual GHG emissions for 2000–2005. Our observations show that extreme air pollution episodes in Southeast Asia are no longer restricted to drought years. We expect major haze events to be increasingly frequent because of ongoing deforestation of Indonesian peatlands.

Towards sustainable management of Indonesian tropical peatlands

“…Peat fires contribute strongly to CO 2 emissions and also cause smoke and haze (Marlier et al 2015a;Heil et al 2007). Because of often incomplete burning, the smoke contains a mixture of various gases including carbon monoxide, carbon dioxide, methane, ammonia, hydrogen cyanide, benzene, toluene, ethylbenzene, xylenes, formaldehydes, nitrous oxide, mono-nitrogen oxides, ethane, propone, butane, acrolein, acid gases, and particulate matter (PM or soot) (Stockwell et al 2016;Gaveau et al 2014;Heil et al 2007). In the dry season, in particular during EL Nino years, smoke can cover major parts of Indonesia and even neighboring countries (Islam et al 2016), with associated effects on human health.…”

Greenhouse gas emissions along a peat swamp forest degradation gradient in the Peruvian Amazon: soil moisture and palm roots effects

“…The challenges that Peruvian peatlands face are substantially different from those in Southeast Asia. Therein Southeast Asia, peatlands are under great pressure from agricultural expansion, artificial drainage, and fires, which result in considerable GHG emissions (Gaveau et al 2014;Hergoualc'h and Verchot 2014). In contrast, anthropogenic degradation of peatland in the Peruvian Amazon is mostly related to recurrent harvesting of M. flexuosa palms from natural stands without drainage or fire.…”

Tropical Peatland Burn Depth and Combustion Heterogeneity Assessed Using UAV Photogrammetry and Airborne LiDAR

“…Due to the high bulk density and carbon content of peat, and the fact that DoB can extend to tens of cm, landscape fire fuel consumption per unit area in tropical peatlands is amongst the highest of any biome worldwide. However, the range in DoBs expected between different types of peatland biome and between different fires means that the carbon emission estimates derived from the burned area based approach remain rather uncertain, and whilst burned area and peat bulk density are increasingly well measured [12][13][14], few DoB estimates exist currently. The existing spatially explicit DoB measurements available, beyond a few point-based measures derived via the use of metal rods to assess subsidence after burning [1,4], have mostly been assessed using light detection and ranging (LiDAR) approaches [9,15].…”