Biomass Burning in North Africa and Its Possible Relationship to Climate Change in the Mediterranean Basin

Abstract

This manuscript assesses whether biomass burning in North Africa could affect the heat budget of the Mediterranean region. The principal biomass burning activities in North Africa are forest and maquis fires, burning of agricultural wastes, and the domestic use of firewood. In the Mediterranean zones of the five North African nations, forest fires emit 1.33 Gg yr⁻¹ of black carbon to the atmosphere; burning of agricultural wastes, 7.27 Gg yr⁻¹, and burning of fuelwood, 5.16 Gg ye⁻¹. The working model calculates maximum atmospheric black carbon emissions during August, September, and October as a result of forest fires and burning of agricultural residues. The atmospheric loading of North African black carbon from the estimated burning activities ranges between 0.01 and 0.05 µg BC m⁻³. This estimated black carbon loading is low compared to observations of the western Mediterranean aerosol, which suggests that the European continent, rather than North Africa, is the likely source region for black carbon in the Mediterranean aerosol. While North African biomass burning may be insignificant on a global scale, the emitted particulates could potentially affect the Mediterranean climate. From estimates of Saharan dust, black carbon, and biomass burning aerosols transported to the north over the Mediterranean Sea, I have calculated the relative optical depths of these three categories of particulates. The optical depth of summed black carbon and biomass burning aerosols is only seven percent that of Saharan dust. Thus, North African biomass burning particulates cause a small impact on the Mediterranean climate and heat budget compared to Saharan dust particles.