Abstract
When organic peat soils are sufficiently dry, they become flammable. In
Southeast Asian peatlands, widespread deforestation and associated
drainage create dry conditions that, when coupled with El Niño-driven
drought, result in catastrophic fire events that release large amounts
of carbon and deadly smoke to the atmosphere. While the effects of
anthropogenic degradation on peat moisture and fire risk have been
extensively demonstrated, climate change impacts to peat flammability
are poorly understood. These impacts are likely to be mediated primarily
through changes in soil moisture. Here, we used neural networks (trained
on data from the NASA SMAP satellite) to model soil moisture as a
function of climate, degradation, and location. The neural networks were
forced with regional climate model projections for 1985-2005 and
2040-2060 climate under RCP8.5 forcing to predict changes in soil
moisture. We find that reduced precipitation and increased evaporative
demand will lead to median soil moisture decreases about half as strong
as those observed during recent El Niño droughts. Such reductions may be
expected to accelerate peat emissions. Our results also suggest that
soil moisture in degraded areas with less tree cover may be more
sensitive to climate change than in other land use types, motivating
urgent peatland restoration. Climate change may play an important role
in future soil moisture regimes and by extension, future peat fire in
Southeast Asian peatlands.