Growth in SSA has been low in the recent past, but there is much room for recovery, which will lead to strong, if modest growth. All of SSA should see an average of 3.9% growth out to 2050. Central and Western SSA will see fairly stable to slightly increasing growth with most countries ex­periencing annual growth in the 5-6% range. The remain­der of SSA will see strong increases in GDP growth rates as recovery continues. Though many countries in East and Southern SSA will be experiencing growth less than 4% out to 2025, all of these countries are projected to see growth rates reach 6 to 9% by 2050.

5.3.2.5 Livestock

The reference run was implemented in the following way: First, global livestock systems were mapped for the baseline year (2000) and for the reference run for 2030 and 2050, using the reference populations and General Circulation Model (GCM) scenarios for these years. The latter was used to generate surfaces of length of growing period (number of days per year) to 2030 and 2050. In the absence of GCM output for diurnal temperature variation and maximum or minimum temperatures, average monthly diurnal tempera­ture variation was estimated using a crude relationship in­volving average (24 hour) daily temperature and the average day-time temperature. The 0.5° latitude-longitude grid size of the GCM data was downscaled to 10 arc-minutes (0.17° latitude-longitude), and characteristic daily weather data for the monthly climate normal for the reference run in 2030 and 2050 were generated using the methods of Jones and Thornton (2003). For the second part of the analysis, the livestock numbers that were generated as output from the IMPACT model at the resolution of the FPUs were converted to live-animal equivalents using country-level ratios of live-

to-slaughtered animals from FAOSTAT for 1999-2001 (the same base that was used for the IMPACT simulations). To es­timate changes in grazing intensity, the extent of each system type within each FPU was estimated, and livestock numbers within each FPU were allocated to each system within the FPU on a pro-rata basis. Existing global ruminant livestock distribution maps for current conditions were used as a basis for the future variants, to derive the livestock allocation pro­portions appropriate to each system within each FPU.

     The eleven livestock systems in the Seré and Steinfeld classification were aggregated to three: rangeland systems, mixed systems (rainfed and irrigated), and "other" systems. These "other" systems include the intensive landless sys­tems, both monogastric (pigs and poultry) and ruminant.

5.3.2.6 Trade

Trade conditions seen today are presumed to continue out to 2050. No trade liberalization or reduction in sectoral protection is assumed for the reference world.

5.3.2.7 Water

Projections for water requirements, infrastructure capacity expansion, and water use efficiency improvement are con­ducted by IMPACT-WATER. These projections are com­bined with the simulated hydrology to estimate water use and consumption through water system simulation by IM­PACT-WATER (Rosegrant et al., 2002). "Normal" priority has been given to all sectors, with irrigation being the low­est, compared with domestic, industrial and livestock uses.

     The hydrology module of the IMPACT-WATER global food and water model derives effective precipitation, poten­tial and actual evapotranspiration and runoff at these 0.5 degree pixels and scale them up to the level of FPUs, which

Region

2000-05

2005-10

2010-15

2015-20

2020-25

2025-30

2030-35

2035-40

2040-45

2045-50

NAE

3.3%

2.2%

2.8%

2.8%

2.7%

2.5%

2.3%

2.0%

1.8%

1.7%

CWANA

4.3%

3.6%

3.7%

3.6%

3.5%

3.8%

4.1%

4.5%

4.8%

5.0%

LAC

4.3%

1.1%

3.7%

4.6%

4.4%

4.4%

4.5%

4.6%

4.6%

4.5%

SSA

3.6%

3.4%

4.2%

4.3%

4.4%

4.6%

4.9%

5.1%

5.2%

5.2%

ESAP

3.2%

2.7%

3.7%

3.8%

3.6%

3.7%

3.7%

3.8%

3.8%

3.7%