Fast-Growing African Populations Risk More Civil Wars
01 May 2010
Keeping a check on African population growth will reduce the frequency of civil conflicts that have killed and maimed millions of people in sub-Saharan Africa. That is the central conclusion of new research by Markus Brückner, published in the May 2010 issue of the Economic Journal.
His study finds that increases in population size can substantially raise the risk of civil conflict in countries in sub-Saharan Africa. A 5% increase in the population size of sub-Saharan countries during the period 1981-2004 increased the risk of civil conflict by up to six percentage points.
That is a large effect given that the baseline probability of a civil conflict outbreak in sub-Saharan Africa is around 5%. Roughly speaking, these estimates imply that doubling the population size of a typical sub-Saharan country will lead to an outbreak of civil conflict with near certainty.
Why should we care?
Neoclassical growth economists have long recognised that a larger population size is associated with lower per capita income levels.
This research shows that not only is there a clear benefit from limiting population growth in terms of per capita income, as emphasised by neoclassical growth models. Keeping a check on African population growth will also reduce the frequency of civil conflicts that have killed and maimed millions of people in sub-Saharan Africa.
The methodological challenge
Obtaining an estimate of the causal effect of population size on the risk of civil conflict is a difficult task. First, civil conflict itself has large negative effects on the country's population size. This is not only because of battle casualties: civil conflicts also induce thousands of people to migrate to other countries.
Second, there is the issue of third factors that are correlated with both population size and civil conflict risk that could lead to spurious estimation results. These 'identification' issues have seriously complicated empirical research on the causal effect that population size has on civil conflict risk.
This study addresses these identification issues by using a so-called 'instrumental variables' approach. The instrumental variables estimation strategy exploits the fact that the sub-Saharan population size significantly decreased during times of severe drought. Because extreme rainfall shortage is a random event, it constitutes a source of exogenous variation for sub-Saharan population growth.
This study addresses the important issue that rainfall shortage also affects aggregate productivity by treating GDP per capita as an endogenous regressor in the instrumental variables estimation.
The population size of sub-Saharan countries has grown over the past decades at an average rate of about 2.5%. According to World Bank calculations, the number of people living in sub-Saharan Africa is projected to double in the next 30 years. These estimates show that this tremendous increase in population size will place the sub-Saharan region at a higher risk of suffering from civil conflict.
The author concludes:
- 'Policy-makers concerned with the stability of African nation states should therefore consider special efforts to limit African population growth.
- 'Because each individual does not take into account the 'negative externalities' that having too many children has for state stability – which is a public good – there is a strong case here for government action.'
'Population Size and Civil Conflict Risk: Is there a Causal Link' by Markus Brückner' is published in the May 2010 issue of the Economic Journal. Markus Brückner is at the Universitat Pompeu Fabra.
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