Projected effects of climate and development on California fire emissions

Background/Question/Methods

Changing climatic conditions are influencing large wildfire frequency, a globally widespread disturbance that affects both human and natural systems. With implications for both mitigation and adaptation strategies, understanding how population growth and development patterns will affect large fire frequency is paramount for climate change adaptation planning. We quantified the effects of a range of population growth and development patterns in California on emissions projections from large wildfires for climate projections under two global emission scenarios.  One of the largest sources of uncertainty lies in the growth trajectory of future vegetation because of the impacts on biomass available for combustion. We modeled future forest growth in a reduced region of the larger domain to estimate the effect that changing forest growth as a function of climate could have on future emissions.

Results/Conclusions

We found that population growth and development patterns are unlikely to result in substantial changes on statewide fire emissions. However, end-of-century emissions projections are 41% larger than the baseline period because of increased large fire frequency on public lands. Our future forest growth projections indicate that in mixed-conifer forest in the Sierra Nevada Mountains, forest biomass may increase 4.8-14.6 Mg ha^-1 on average by mid-century. While mid-century increases in forest biomass could increase fire emissions, climate effects on forest recovery following wildfire may be a limiting factor on subsequent emissions.