iii. Lambin and Meyfroidt 2011
These authors summarize various estimates for land demand in 2030 Table 4 and show a global need for unused lands to be allocated to new croplands,
biofuel crops, grazing lands, industrial forestry, and urban expansion. The low estimates represent a conservative view of both land reserve and
additional land demand whereas the high estimates represent a slightly bolder view.
Table 4. Estimates of land use in 2000 and additional land demand for 2030
2.2.2. Amazon Basin
The scenarios of global land demand highlight risks and concerns related to the preservation of tropical forests. These forests hold an enormous amount
of carbon in vegetation and soil and huge biodiversity, relating to concerns about climate change deforestation, hydrological cycle and ecosystem
services. Several research groups and researchers are looking at this pressure through both monitoring and mapping current changes in land
cover and use, and also developing scenarios aiming to glimpse the impacts
of different strategies at different scales global, regional, local. Within the Amazon region, most of these scenarios are constructed for the Brazilian
Amazon, which has the largest area within the biome and the greater historical changes in land use and deforestation rates, especially until 2004.
Moreover, the Brazilian Amazon has a consistent and reliable land use and cover monitoring system from which data is used as a reference for the
construction of most of the spatial models.
A current effort to produce land cover and land use change data for the entire basin will lead to an increase of land use change scenarios at the
Amazon Basin scale e.g. RAISG, 2012 and Terra-I, 2012. Gómez and Nagatani et al. 2009 developed four scenarios for the Amazon Basin from
2006-2026, based on consultation with stakeholders and decision-makers. The construction of these scenarios was founded on the identification and
analysis of driving forces from which three critical uncertainties were selected; these were used to build the fundamental premises for each
scenario: role of public policies regulating the use of natural resources, market behaviour and science, technology and innovation. Combining
these three critical uncertainties four scenarios were developed: •
Emergent Amazonia: improvement in the role of public policies; market forces provide incentives for sustainable production;
and a reduction in the available science, technology and innovation necessary to optimize the sustainable use of its resources.
• Inching along the precipice: improvement in the role of
public policies; market forces provide incentives for the development of non-sustainable production; and a reduction in the available
science, technology and innovation. •
Light and shadow: improvement in the role of public policies; market forces provides incentives for the development of
non-sustainable production; and an improvement in the available science, technology and innovation.
• The once-green hell: a reduction in the role of public
policies; market forces provide incentives for the development of non-sustainable production; and an improvement in the available
science, technology and innovation. This work also analyzed other drivers, both socioeconomic and
environmental aspects, which helped shape the scenarios summarized in Figure 3. Amazonia presents a complex heterogeneous system and
generalized scenarios face risks and uncertainties based on the diversity of contexts and local social processes.
Figure 3. Behavior of the driving forces of Geo-Amazonia 2005 scenarios
Most of land use change scenarios described in the literature only address human drivers of deforestation and do not consider the stress of
climate change in land use change patterns. The study of Malhi et al. 2008 addresses the deforestation of the Amazon considering the impact of climate
change as a relevant driver in future land use cover and change. This study compiled deforestation and climate change scenarios, overlapping and
crossing them to show the possible links and relationship. In Figure 4 two scenarios to 2050 are shown.
Figure 4. Loss of forest cover overlapped with drought probability for 2050 Malhi et al., 2008. A Business as usual scenario. B Increased governance scenario.
Besides external demand and climatic variables, internal factors significantly influence land use change in the region. Many authors discuss
these drivers, especially for Brazilian Amazon for which various scenarios have been constructed using this approach. Soares-Filho et al. 2006
analysed the influence of conservation initiatives, especially protected areas, and also considered the impact of new paved roads as a key factor related to
changes in land use in the region. This study, which covers all, but only, the Amazon Basin, developed eight scenarios for 2050, considering increases in
infrastructure through paved roads, the enforcement of environmental and land tenure law and protected areas. The more pessimistic scenario
Business-as-usual assumed that the current deforestation trend would continue, roads would be paved, legal reserves would not be complied with
and new protected areas would not be created. On the other hand, a more optimistic scenario Governance included the enforcement of forest
reserves, agro-ecological zoning of land use and the creation of new protected areas. The remaining scenarios were intermediate. This study
shows a reduction from 5.3 million km
2
to 3.2 million km
2
of closed-canopy forest in the Amazon for 2050 in the Business-as-usual scenario and to 4.5
million km
2
in the Governance scenario. Intermediate scenarios show that half of the reduction of deforestation is due to expanding protected areas
and enforcement. Figure 5 shows the spatial distribution of deforestation in both extreme scenarios.
Figure 5. Model results for forest cover in the extreme-case scenarios in the year 2050 in the Amazon Basin Soares-Filho et al. 2006. a Forest cover for Business-as-usual
scenario b Forest cover for Governance scenario
2.2.3. Brazilian Amazon
