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5 The sustainable scenario

A possible and desirable scenario for the sustainable development of the region was identified (Furtado, 1984; GallopÍn, 1986, 1989b; Winograd, 1989a). This scenario emphasizes the satisfaction of the needs of the population, a better distribution of wealth, and a partici patory and decentralized approach. It assumes the implementation of national and regional environmental policies and an active strategy for research and development (R&D) focused upon regional problems and opportunities; the implementation of social and economic reforms; land use zoning and regulation of the agricultural frontier; policies for the reinforcement of the industrial sectors associated with renewable and nonrenewable natural resources and agriculture; the development of local energy sources (mainly hydroelectricity and biomass); promotion of technological innovations in relation to the revalorization of the renewable natural resources and to the development of new sustainable productive uses and internal and international market "windows of opportunity," particularly in relation to tropical forests and agricultural production.

In terms of environmental sustainability, the issues of technological pluralism (complementary use of traditional, modern, and high technology) and of technological blending (constructive integration of new and emerging technologies into traditional or modern technologies) will assume paramount importance, requiring new forms of social organization and an integrated strategy for technological development and diffusion. The reevaluation and upgrading of traditional technology and of the empirical knowledge existing in the region will be specially important for the medium and small-scale sectors of the rural areas. While many of the traditional technologies are extensive rather than intensive, they are often well adapted to the local ecological and social characteristics. They represent a good basis for building new, efficient, high-yielding, and ecologically sound production systems. A number of already tested systems of forestry, agroforestry, and agro-silvo-pastoralism support this point (Hecht, 1981).

Special emphasis will be given to the development of new systems of production based on the utilization of the ecosystems already altered, including the "neo-ecosystems" generated by past human activities on virgin and abandoned lands, and to modernization and yield improvements in the high-quality lands that are already being exploited.

Strategies will be developed concerning the allocation of ecological areas for protection (and in some cases management) of large-scale ecological functions and processes (i.e. watershed regulation, biogeo-chemical cycles, etc.), often requiring cooperation among different countries.

Regarding the major rural productive activities, integrated production systems will be favoured when appropriate. Particular emphasis will be placed upon the development of productive activities according to ecological suitability zoning (see table 2.11). A general criterion is the maintenance (at least during a transition period) of productive pluralism, with the coexistence of different types of agriculture, integrated through subnational, national, and regional policies GallopÍn, 1988). Structural reforms and technological innovations directed towards the transformation of the present subsistence agricultural sector into an efficient and sustainable peasant agriculture will be required. New forms of hightechnology diversified agriculture will be developed, directed towards the selective exploitation of the local genetic resources for food, medicine, industry, and so on. It will imply the development of technologies for a new efficient agriculture in diversified ecosystems, as well as new ranching and wildlife management systems, viewing ecological diversity, heterogeneity, variability, and singularities as resources rather than as hindrances or constraints. Forestry will emphasize the re-evaluation of the forests as multipurpose producers (wood, energy, wildlife, special products, ecological functions).

The scenario was derived using the following conclusions from the EPLA project:

1. There are no important ecological constraints (at the regional level) to the satisfaction of human needs and to sustainable development, including food production. It is not necessary to sacrifice conservation areas needed to maintain essential ecological functions and services (Coutou, 1988; (Gómez and (GallopÍn 1989a, 1989b; Higgins et al., 1982; Morello et al., 1989).
2. There is no lack of available technologies impeding the sustainable management of Latin American ecosystems. Even where more research is needed and knowledge of the management of some ecosystems is seriously incomplete, there exist many socially, economically, and ecologically sustainable management techniques for a wide variety of ecosystems (Fuentes Godo, 1989; Gligo, 1989; Winograd, 1989a, 1989b).
3. Regarding new and emerging technologies, the following broad regional priorities for R&D will be emphasized (GallopÍn 1987): (i) the fertility limitations of tropical red soils (covering 50 per cent of South America) for traditional agriculture; (ii) sustainable use of deserts and semi-deserts (covering 15-20 per cent of South America and 35-40 per cent of Central America and Mexico) and of superficial and underground freshwater; (iii) sustainable management of tropical forests and their ecological functions; (iv) management and protection of regional germplasm and wildlife; (v) sustainable increment of agricultural yields and sustainable livestock management; (vi) evaluation and use of the regional empirical cultural experiences in agro-ecological management; (vii) management and conservation of fragile ecosystems; (viii) management, rehabilitation, and restoration of degraded or overcharged regional environments;(5) (ix) management of the stabilized "neo-ecosystems" generated by human actions; (x) treatment of regional and sub-regional bio-geo-chemical cycles and intercountry coordination of human activities affecting them. (The general hypothesis for variables directly affecting land use appears in table 2.5, above.)

Table 2.11 Land use suitability for the tropical life-zones of Latin America (surface area in 10³ Km²; percentages in parentheses)

Source: Winograd, 1989a.

Key: T&ST F = tropical and subtropical moist forests
T&ST MF = tropical and subtropical montane moist forests
T&ST DF = tropical and subtropical dry forests
TS = tropical savannas
D&M = tropical and subtropical deltas and mangrove forests
P&P = paramo and puna
T&ST DDS = tropical and subtropical deserts and dry scrub

Under the sustainable scenario, the simulations indicate that the region is capable of satisfying the agricultural, livestock, fishing, and forestry internal requirements in a sustainable manner within the considered time-horizon of the next forty years, with a substantial surplus for exports.

Three major processes account for a large part of the dynamics in this scenario: ¹ implementing science and technology and economic policies emphasizing the productive rehabilitation of deteriorated and altered ecosystems, which cover 20 per cent of the total land area; ² implementing policies favouring integrated rural production systems (agriculture-animal husbandry-forestry-aquaculture) whenever appropriate; and ³ actively implementing policies directed to integrating the new technologies into traditional and modern technologies.

The results from the simulation runs under the sustainable scenario appear in aggregated form in table 2.12, and for each life-zone in table 2.13.

Table 2.12 Simulated total changes in land categories for tropical Latin America 198O-2030. under the sustainable scenario

Table 2.13 Evolution of land use under the sustainable scenario (10³ Km²)

Source: Winograd, 1989a.

Key: T&ST F = tropical and subtropical moist forests
T&ST MF = tropical and subtropical montane moist forests
T&ST DF = tropical and subtropical dry forests
TS = tropical savannas
D&M = tropical and subtropical deltas and mangrove forests
P&P = paramo and puna
T&St DDS = tropical and subtropical deserts and dry scrub

In addition to the quantitative differences with the pattern derived from the current trends, the qualitative changes in the modality of rural production imply a drastic reduction of the ecologically degrading processes exhibited by the reference scenario. For the whole region those figures imply the transformation of 2.2 million hectares per year of virgin and semi-virgin ecosystems. Protected areas represent 45 per cent of the remaining natural ecosystems. Altered ecosystems will cover 19 per cent of the area, the same figure as in the reference scenario. However, in this case most of the altered lands become productive lands (13 per cent under sustainable forestry and 6 per cent in rehabilitation). Cultivated lands increase to 13 per cent (10 per cent under intensive agriculture and 3 per cent under shifting cultivation). Rangelands decrease because of increments in carrying capacity (14 per cent is under intensive and semi-intensive grazing systems and 10 per cent is integrated with forestry). Eight per cent of the land will be under agroforestry. As a consequence of the rehabilitation and restoration activities, wastelands are reduced.

The ecological and technical feasibility of the sustainable scenario is supported by a number of additional considerations. By conservative estimates, not less than 15 per cent of the territory of tropical Latin America is suitable for crop agriculture (7.5 per cent for intensive agriculture and 7.5 per cent for agroforestry, agro-silvo-pastoralism, and shifting agriculture) (Winograd, 1989a). The requirement of agricultural lands in order to nourish the total projected population of Latin America by the year 2030 is estimated as 4 per cent of the total land surface under a high level of agricultural inputs, 7 per cent if an intermediate level is used, and 19 per cent with a low input level agriculture (Gómez and (GallopÍn 1989a). The major constraint to food production (at the regional level) is thus not the absolute scarcity of agricultural land, but the low effectiveness of its utilization. Only 65 per cent of the tropical agricultural lands are harvested annuallv (FAO 1986): however. this figure can be increased to at least 85 per cent. This implies a large potential increase in agricultural production by the improvement of this single factor.

On the other hand, the agroclimatological conditions in 75 per cent of the tropical areas of the region permit up to 2.5 annual harvests of short-cycled crops. The yields of those crops can be duplicated just by applying currently known technological systems (FAO, 1981, 1988).

Taking all those factors into account, it can be estimated that average food production could be multiplied by four within a relatively short period, merely by introducing known technical improvements in the allocation and utilization of agricultural land.

Agricultural land availability will reach 0.32 hectares per person in the year 2030 (table 2.7, above).

Important improvements are also feasible regarding tropical ranching, which currently exhibits a very low efficiency. By using existing techniques (Hecht et al., 1988), production can be increased from the present 45 kg/ha/year to 90-120 kg/ha/year and animal loads from 0.6 AU/ha to 1.5 AU/ha. This would allow increased production while reducing by 30 per cent or more the extent of pasture lands, land that could be allocated to more sustainable uses (Winograd, 1989a).

Other major opportunities for sustainable development are associated with the richness and diversity of the flora and fauna of the Latin American tropics, a potential much underutilized so far. It is estimated that 36 per cent of the 250,000 known species of flowering plants live in the region. About 1,000 plant species have a clear economic potential (Myers, 1984; Tosi, 1980). About 250 plant species and 45 animal species of the Andean mountain areas are appropriate for cultivation or domestication (Patiño, 1982). The tropics of the region possess areas with the capacity to provide unique products: in the puna, for instance, more than 30 potato varieties are grown, and a large economic potential exists for the production of fine wool from camelids such as alpaca, vicuña, and llama (CEPAL/PNUMA, 1983b). These alternative production systems can be not only ecologically but also economically better suited than the prevailing ones (see table 2.14 for some illustrative examples).

In the sustainable scenario, it is anticipated that carbon dioxide emissions from biotic sources would be reduced by 90 per cent from the 1980 level, to about 55 x 10(6) tons of carbon per year (table 10, above) by the year 2030. This is associated with the strong reforestation emphasis embodied in the scenario, aiming at a reforestation rate of 1.3 million hectares per year. This would result in 64 million hectares reforested by the year 2030. This represents 14 per cent of the new reforested area that could compensate the excess atmospheric carbon due to human activities (Sedjo, 1989). This value should be compared with the present estimated regional biotic emission of between 8.5 and 10.4 per cent of the world total.

Table 2.14 Some examples of alternatives systems of production for tropical areas of Latin America

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