Greenhouse gas induced changes in the fire risk in Brazil in ECHAM5/MPI-OM coupled climate model

Abstract

Vegetation fires are the second largest source of greenhouse gas emissions to the atmosphere. The reduction of the climatic impact of these emissions is related to the vegetation susceptibility to fire (fire risk), as well as to the understanding of possible implications of changes in atmospheric circulation on fire risk in the nearfuture. This study evaluates the environmental susceptibility to fire occurrence based on a Potential Fire Index (PFI). Two climate simulations from the ECHAM5/MPI-OM climate model have been used to calculate the PFI: present day and an experiment for the end of the twenty-first century (2080-2100). The results indicate that the proposed PFI methodology could properly reproduce the areas with the highest fire incidence under present conditions. Moreover, it was found that under greenhouse warming conditions the PFI foresees an increase in the fire risk area, particularly for the Amazon region. We concluded, furthermore, that changes of vegetation predicted to occur in the future lead to substantial modifications in the magnitude of the PFI, and may potentially extend the length of the fire season due to induced longer drought periods as compared to current conditions.

Modelling Weather and Climate Related Fire Risk in Africa

“…Type and natural cycle of vegetation phenology, maximum temperature and relative humidity of the air are also required to compute the PFI. The reference of the calculations is the Number of Dry Days or Days of Drought (DD), which is the number of days without precipitation during the proceeding 120 days [18]. For the PFI calculation, a set of parameterization equations applied for Brazil are utilized for Africa.…”

“…For the PFI calculation, a set of parameterization equations applied for Brazil are utilized for Africa. It is briefly described below, and is presented in details by [18]. A set of modification are conducted, however, to compute the basic risk (BR) for the African vegetation types considered:…”

“…where the values a = −0.006, b = 1.3, c = 0.02 and d = 0.4 are taken from [18]. RH min is the minimum daily relative humidity and T max is the maximum daily temperature.…”

“…[14][15][16][17]. It has also been demonstrated that changes induced in biome distribution may also alter atmospheric/landscape susceptibility to fire occurrence [18,19]. Reference [20] argued that the clearing of tropical savannas increases temperatures and wind speeds while reducing precipitation and relative humidity.…”

“…Using the Potential Fire Index (PFI), [18] found that under greenhouse warming conditions the PFI indicates an increase in the fire risk area, particularly for the Amazon region. Model-based investigations have also been conducted to understand the interaction between fire, the CO 2 fertilization effect and Earth's ecosystems and dominant plant communities [e.g.…”