countries such as China, India and Brazil in line with rapid economic growth. O‘Neill et al (2010) estimate that slowing population growth could reduce carbon emissions significantly. Indeed it has been argued that the prevention of unwanted births today is likely to be one of the most cost-effective ways to preserve the planet‘s environment in the longer term (Birdsall 1994).

# **4.   Implications for Sub-Saharan Africa**

Sub-Saharan Africa is now the developing region closest to the scenario described by many as that in which rapid population growth is most difficult to accommodate because of slow productivity growth. As Weil and Wilde (2009:259) conclude from their study: ―The Malthusian channel by which a high level of population reduces income per capita is still relevant in poor developing countries that have large rural populations dependent on agriculture, as well as in countries that are heavily reliant on mineral or energy exports.‖ Fertility rates remain high in much of Sub-Saharan Africa, with a regional average of 5.1 children per woman in 2008 ― matched outside the region only by 4 small war-torn countries<sup>9</sup> (World Bank 2010b: Table 2.19). Although fertility has declined in many countries in this region,<sup>10</sup> only a few have a TFR below 4.<sup>11</sup> High fertility also helps keep maternal mortality high (section 5.1) ― Sub-Saharan Africa has an estimated 1:31 lifetime risk of maternal death, which is _four times higher_ than that of developing regions as a whole (WHO et al 2010: Table 2).

Between 1970 and 2005, the population aged below 15 years grew by 150 percent in Sub-Saharan Africa as a whole, and by over 200 percent in the high-fertility country of Niger ― compared with 30 percent for Asia, and 36 percent for Latin America (Figure 2). As a result, Sub-Saharan Africa has as yet benefited far less than other regions from the impact of reduced dependency ratios on per capita output growth (Kelley and Schmidt 2005, Eastwood and Lipton 2011).

This region is estimated to have depleted ―genuine wealth per capita‖ quite rapidly during 1970-2000 (Arrow et al 2004, Dasgupta 2010): ―Population growth implies significant differences between the initially estimated growth rate of genuine wealth... and the growth rate on a per capita basis.... At an annual rate of decline of 2.6 percent in genuine wealth per annum, the average person in the sub-Saharan Africa region becomes poorer by a factor of two about every 25 years.‖ (Arrow et al 2004: 164-5) Although it has an enormous wealth of resources, including land and minerals, policy environments in many countries have not been conducive to rapid growth in average living standards. Growth in real GDP per capita during 1960-2004 was only 24% in the Sub-Saharan African region, compared with 108% on average in low-income countries, and 685% in the East Asian region (Figure 3). The region as a whole showed low growth despite rapid growth in some countries, including Botswana and Mauritius. This is because several populous countries show low growth: population growth rates from 1960-2004 were higher for countries with large- and medium-sized populations than for those with small ones (World Bank 2007a:33-35). More recently the annual percentage growth in GDP has risen (at constant prices) to around 5.6% per year during 2004-07 (IMF 2010a), and similar rates are projected for the region for 2011-12 (IMF 2011: Box 1). Some countries are growing much faster. However, the regional GDP growth is nearly halved on a per capita basis by population growth.

Agricultural production per capita was stagnant during 1960-2005, whether measured in overall food production per capita (Figure 4) or cereal yields per hectare (World Bank 2007b:Fig 2.1) ― in sharp contrast to rapid growth in these indices in Asia and Latin America. Agricultural stagnation is an especial 11