The spatial distribution and temporal drivers of changing global fire
regimes: a coupled socio-ecological modelling approach
Abstract
In the Anthropocene, humans are the largest drivers of change in
vegetation fire regimes. Humans influence fire regimes both directly, by
starting, managing and extinguishing fires, and also indirectly by
altering fuel composition and connectivity. However, whilst vegetation
fire is a coupled socio-ecological process, representation of human
influences on fire regimes in global-scale modelling remains limited.
This places a fundamental constraint on our ability to understand how
human and natural processes combine to create observed patterns of
vegetation fire, and how such processes may interact under future
scenarios of socioeconomic and environmental change. Here, we respond to
this challenge by presenting a novel integration of two global and
process-based models. The first is the Wildfire Human Agency Model
(WHAM!), which draws on agent-based approaches to represent
anthropogenic fire use and management. The second is JULES-INFERNO, a
fire-enabled dynamic global vegetation model, which takes a
physically-grounded approach to the representation of vegetation-fire
dynamics. The WHAM-INFERNO combined model suggests that as much as half
of all global burned area is generated by managed anthropogenic fires –
typically small fires that are lit and then spread according to land
user objectives. Furthermore, we demonstrate that including
representation of managed anthropogenic fires in a coupled
socio-ecological simulation can improve understanding of the drivers of
unmanaged wildfires. Overall, findings presented here have substantial
implications for understanding of present-day and future fire regimes,
indicating that socio-economic change may be as important as climate
change in determining the future trajectory of fire on Earth.