سوخت های زیستی و توسعه اقتصادی: تجزیه و تحلیل تعادل عمومی قابل محاسبه برای تانزانیا

Biofuels could offer new economic opportunities for low-income countries. We use a recursive dynamic computable general equilibrium model of Tanzania to evaluate different biofuels production options and estimate their impacts on growth and poverty. Our results indicate that maximizing the poverty-reducing effects of biofuels production in countries like Tanzania will require engaging and improving the productivity of smallholder farmers. Evidence shows that cassava-based ethanol production is more profitable than other feedstock options. Cassava also generates more “pro-poor” growth than sugarcane-based systems. However, if smallholder yields can be improved rather than expanding cultivated land, then both sugarcane and cassava out-grower schemes generate similar pro-poor outcomes. We conclude that, in so far as the public investments needed to establish a biofuels industry are consistent with other development needs, then producing biofuels will enhance economic development in countries like Tanzania.

Many low-income countries see biofuels as an opportunity to promote development (Ewing and Msangi, 2009). Tanzania, for example, is considering establishing a domestic biofuels industry in order to stimulate agricultural growth, create jobs and reduce rural poverty (Arndt et al., 2011b). Evidence suggests that optimism about biofuels in developing countries may be justified. In Mozambique, for example, Arndt et al., (2011a) find that proposed large-scale biofuels investments will increase economic growth by half a percentage point each year over the coming decade and lift 5% of the population above the national poverty line. This supports the view held by some that biofuels could help low-income countries overcome their dependence on oil imports while also reducing greenhouse gas emissions and increasing farmers' participation in the growth process (see, for example, FAO, 2008). Optimism over biofuels is countered by uncertainty over possible trade-offs between biofuels and food production, and the effects that declining food supplies may have on poverty and food insecurity. This concern has received considerable attention in the biofuels debate and has gained support after the 2008 global food crisis (Headey and Fan, 2008 and Rosegrant, 2008). Shifting resources away from food production could increase households' reliance on marketed foods, and biofuels may not raise the incomes of poor households enough to offset higher food prices. Finally, biofuels may not reduce greenhouse gas emissions once the effects of land clearing and fertilizer use are considered (Melillo et al., 2009 and Searchinger et al., 2008).

Considerable debate exists concerning the gains from establishing biofuels industries in low income countries, particularly over possible trade-offs between biofuel and food production. It is therefore crucial that governments in countries like Tanzania understand how different biofuel technologies contribute to achieving national development objectives. Drawing on detailed production cost estimates, this study developed a recursive dynamic economywide model of Tanzania to estimate the growth and distributional implications of alternative biofuels production scenarios. These scenarios differed in the feedstock used to produce biofuels (sugarcane and cassava), the scale of feedstock production (small-scale out-grower versus larger-scale plantations), and the way in which feedstock production is increased (yield improvements versus land expansion). Model results indicate that while some individual farmers may shift resources away from producing food crops, there is no national-level trade-off between biofuels and food production in Tanzania. Rather, it is traditional export crops that will be adversely affected via the mechanism of a sizable appreciation of the real exchange rate alongside competition for labor and land. It is the relatively large size of Tanzania's agricultural export sector that prevents food production from contracting. This is because the amount of land displaced by biofuel feedstock is smaller than the lands released by declining traditional export crops. As a result, food production increases slightly under most biofuel investment scenarios. Overall, national GDP rises and new employment opportunities are created in biofuels sectors. This leads to welfare gains throughout the income distribution, albeit following a possible period of adjustment in which prices, farm workers and non-biofuel exporters adapt to new market conditions.