A high-resolution Wildfire Risk projections dataset based on the Fire Weather Index is under development. We have now completed the first projection of 1 out of 5 climate models and for one emissions scenario (Shared Socioeconomic Pathway 5-8.5 or SSP5-8.5). The other 4 models and second scenario (SSP1-2.6) are under way. The full high-resolution wildfire risk projections dataset will be available early 2023 to be used in forward looking physical risks assessments under climate change.
Product update (February 2023): Wildfire risk index now available, check Fire Weather Index projections at high-resolution now available.
Wildfire risk refers to the potential likelihood and impacts of wildfires occurring in a given area. Wildfires are uncontrolled fires that spread quickly, engulfing vegetation, wildlife, and potentially human settlements. The risk of wildfires is influenced by several factors, each contributing to the likelihood of ignition and the severity and spread of fires when they do occur. Here are the primary components that contribute to wildfire risk:
The Wildfire Risk Index we are preparing is based on Fire weather, an approach that focuses exclusively on climate and weather weather conditions and how it will evolve under climate change. It us used in a "Ceteris paribus" approach meaning all other drivers remaining constant, which can be considered valid for topography but not for human factors and land-use.
Fire weather refers to specific meteorological conditions that are conducive to the ignition and rapid spread of wildfire risk. These conditions typically include a combination of dry, warm, and windy weather that can dry out vegetation and make it more flammable, thus increasing the likelihood and intensity of wildfires. Key components of fire weather include:
It is a weather variables based index used worldwide to estimate wildfire risk. It accounts for the effects of fuel moisture and wind on fire behavior and spread. The higher the index is, the more favorable the meteorological conditions to wildfire risk. The index used here is the Canadian Forest Fire Weather Index system. It is composed of several model components that account of the effects of the moisture content of the forest floor and weather conditions on fire behavior. It is calculated from five daily weather variables: temperature, relative humidity, wind speed, and 24-hour precipitation.
Risk for present climate (1991-2020) are calculated using data from the ERA5-Land reanalysis. A reanalysis is produced by combining weather models with observations to provide a comprehensive description of recent global climate. The ERA5-Land dataset is provided by the Copernicus Climate Change Services (C3S) and is a world reference for historical climate analysis.
Risk for future climate (2021-2100) are calculated using data from high-resolution climate projections. Those are obtained by statistical techniques called “downscaling” that combine reanalysis data and climate model simulations to increase the spatial resolution of the original climate model data (from hundreds of kilometers to tens of kilometers). We recently produced a high-resolution climate projections dataset, based on the recently published 6th Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), that is coherent with the ERA5-Land reanalysis. This allows to have wildfire risk projections that are coherent with the historical series.
Figure. Future wildfire risk. 30 year average of the Fire Weather Index at the end of the century (2071-2100) for one climate model under Shared Socioeconomic Pathway 5-8.5 (SSP5-8.5).