Impacts of current and projected oil palm plantation expansion on air quality over Southeast Asia

Abstract

Abstract. Over recent decades oil palm plantations have rapidly expanded across Southeast Asia (SEA). According to the United Nations, oil palm production in SEA increased by a factor of 3 from 1995 to 2010. We investigate the impacts of current (2010) and near-term future (2020) projected oil palm expansion in SEA on surface-atmosphere exchange and the resulting air quality in the region. For this purpose, we use satellite data, high-resolution land maps, and the chemical transport model GEOS-Chem. Relative to a no oil palm plantation scenario ( ∼ 1990), overall simulated isoprene emissions in the region increased by 13 % due to oil palm plantations in 2010 and a further 11 % in the near-term future. In addition, the expansion of palm plantations leads to local increases in ozone deposition velocities of up to 20 %. The net result of these changes is that oil palm expansion in SEA increases surface O 3 by up to 3.5 ppbv over dense urban regions, and in the near-term future could rise more than 4.5 ppbv above baseline levels. Biogenic secondary organic aerosol loadings also increase by up to 1 µg m −3 due to oil palm expansion, and could increase by a further 2.5 µg m −3 in the near-term future. Our analysis indicates that while the impact of recent oil palm expansion on air quality in the region has been significant, the retrieval error and sensitivity of the current constellation of satellite measurements limit our ability to observe these impacts from space. Oil palm expansion is likely to continue to degrade air quality in the region in the coming decade and hinder efforts to achieve air quality regulations in major urban areas such as Kuala Lumpur and Singapore.

Oil palm and biodiversity: a situation analysis by the IUCN Oil Palm Task Force

“…Isoprene is believed to influence the atmospheric properties that control the condensation of water vapour, thus influencing cloud cover and rainfall (188). Isoprene contributes to a process that involves the generation of hydroxyl radicals which promotes smog and ozone in a polluted environment (190,191). Thus, we can predict that oil palm plantations will exacerbate air pollution in the vicinity of industrial centres with wider consequences for people and the environment.…”

Global climate forcing driven by altered BVOC fluxes from 1990–2010 land cover change in maritime Southeast Asia

“…Previous studies have shown that the sign and strength of the regional surface ozone response to increased isoprene strongly depend on availability of NO X (Ashworth et al, 2012;Silva et al, 2016;Warwick et al, 2013). When applying contemporary NO X emissions from published inventories, both Warwick et al (2013) applied future projections of oil palm expansion for biofuel production.…”

“…Both studies found that inflating the NO X emissions in the region of land conversion enhanced surface ozone concentrations (Ashworth et al, 2012;Warwick et al, 2013). In a study focused on estimating the air quality impacts associated with 2010 oil palm cover compared to a no-oil-palm 30 landscape, Silva et al (2016) simulated increased surface ozone concentrations over much of the region. They found that some low-NO X regions (e.g., parts of Borneo) exhibited surface ozone reductions in response to increased isoprene emissions (Silva et al, 2016).…”

“…In a study focused on estimating the air quality impacts associated with 2010 oil palm cover compared to a no-oil-palm 30 landscape, Silva et al (2016) simulated increased surface ozone concentrations over much of the region. They found that some low-NO X regions (e.g., parts of Borneo) exhibited surface ozone reductions in response to increased isoprene emissions (Silva et al, 2016). The differences in the simulated impacts on regional surface ozone between this study and the Silva et al (2016) While the strongest impacts of regional land cover change on annual-mean surface ozone are confined to Southeast Asia, weak long-range enhancements are simulated, particularly over the tropical ocean (< 1 ppbv over Indian Ocean, < 0.5 ppbv elsewhere) (Figure 1).…”

“…They found that some low-NO X regions (e.g., parts of Borneo) exhibited surface ozone reductions in response to increased isoprene emissions (Silva et al, 2016). The differences in the simulated impacts on regional surface ozone between this study and the Silva et al (2016) While the strongest impacts of regional land cover change on annual-mean surface ozone are confined to Southeast Asia, weak long-range enhancements are simulated, particularly over the tropical ocean (< 1 ppbv over Indian Ocean, < 0.5 ppbv elsewhere) (Figure 1). With decreasing atmospheric pressure, the long-range impact on ozone spreads beyond the tropics and generally grows in magnitude (Figure 1).…”