Fire risk is evaluated as a combination of current weather, ignition sources and fuel loads. Climate changes such as decreasing rainfall, increasing temperatures and more incidences of high temperatures will modify fire risk since:
Drier fuel can result from higher temperature, reduced rainfall and increased lower relative humidity.
Litter production and decomposition rates under enhanced CO2 concentrations can modify the fire fuel loading where increased temperature increases decomposition rates of both leaf litter and woody debris rates – provided there is adequate moisture reducing fuel loads.
Decrease in litter decomposition occurs when C:N ratios are increased, increasing fuel loads.
Increased natural ignition from any increases in thunderstorms frequency.
The productivity and spread of weeds increases with climate change, providing more natural fuel.