Types of weather and urban disasters in the Federal District between 2000 and 2015

Abstract

The increase in atmospheric CO2 concentration and its potential to cause climatic changes brought a new interest in carbon cycle and C sequestration strategies. Carbon balances have been estimated for several regions and ecosystem in the world but are scarce for the semiarid northeastern region. This region covers one million km2, of which caatinga, native pastures, planted pastures and crops occupy 40, 30, 15 and 15%, with biomass stocks of 47, 15, 2 and 1 Mg ha-1, totaling about 1200 Tg of C, and producing 9, 8, 8 and 5 Mg ha-1 year-1, totaling 400 Tg of C year-1. Soil C concentrations were estimated as 9.25 e 5 g C kg soil-1 , in the layers of 0-20 and 20-100 cm depth, totaling 8,9 Pg of C. The opening of new crop fields is equivalent to 2.4 x 106 ha, corresponding to 48 x 106 Mg biomass and24 Tg of C. Firewood consumption corresponds to 17 x 106 Mg biomass, forage consumption to 47 x 106 Mg and agricultural production to 15 x 106 Mg. It is not possible to close a balance of C gains and losses due to lack of information on the balance of native vegetation slash and burn to establish new crop fields and native vegetation regrowth with the abandonment of these fields. There is an unused potential in the marketing of C credits in the areas of regenerating caatinga.