Climate change must be factored into savanna carbon- management projects to avoid maladaptation: the case of worsening air pollution in western Top End of the Northern Territory, Australia

Abstract

Savanna fires are a major source of greenhouse gas (GHG) and particulate pollution globally. Since mid-2006, an Australian Government carbon offset program has incentivised Northern Territory land managers to undertake early dry-season savanna burning with the aim of reducing late dry-season wildfires and associated GHG emissions. The focus of this study is addressing concern that savanna burning carbon abatement projects are causing worsening air pollution in the city of Darwin. Reconstructed concentrations of daily particulate matter of <2.5 μm (PM2.5) since the 1960s showed since 2000s a worsening in PM2.5 in the early dry season (May, June, July), some improvement in the late dry season (August, September, October) with little overall difference for the whole dry season. Remote-sensing PM2.5 estimates in Darwin were correlated with region-wide PM2.5 estimates during the early dry season. Remote-sensing analysis of area burned and intensity of fires since 2002 showed that savanna carbon projects have shifted burning to the early dry season and caused increases in fire intensity compared with non-project areas. Increased fire intensity appears to follow sharply declining fuel moisture, as well as management effects on carbon project areas, which have possibly undermined the efficacy of savanna burning projects in reducing GHG emissions. More thorough evaluation of underlying assumption of savanna burning carbon abatement in Australia and elsewhere in the world is required to avoid maladaptation, such as over-crediting, smoke pollution, and other environmental harms.