Κυριακή 8 Ιουλίου 2018

Does population growth lead to hunger and famine?

Does population growth lead to hunger and famine?
Joe Hasell

Our World in Data presents the empirical evidence on global development in entries dedicated to specific topics.

This blog post draws on data and research discussed in our entry on Famines.

This post is the first of a pair of posts looking the relationship between famines and population growth. Here we consider whether population growth causes famine and hunger. In a second post, we look at the demographic impacts of famines, and in particular the extent to which famines may 'check' population growth.
Modern Malthusians

It’s no good blaming climate change or food shortages or political corruption. Sorry to be neo-Malthusian about it, but continuing population growth in this region makes periodic famine unavoidable – as many people have been pointing out since the last famine. Many of the children saved by the money raised over the next few weeks will inevitably be back again in similar feeding centres with their own children in a few years time.

- Blog entry from British environmentalist, Sir Jonathan Porrit, 11/07/20111

It is not uncommon to see arguments along the lines of this quote from Sir Jonathan Porritt, claiming that famines are ultimately caused by overpopulation. Porritt – former director of 'Friends of the Earth' and also former chairman of the UK Government’s Sustainable Development Commission – was talking about the 2011 famine in Somalia that went on to kill roughly 250,000 people2. He seems certain that the rapid population growth witnessed in East Africa had made famine there ‘unavoidable’.

There is something compelling about this logic: a finite land area, with a limited ‘carrying capacity’, cannot continue to feed a growing population indefinitely. From such a perspective, the provision of humanitarian aid to famine-afflicted countries, however well intended, represents only a temporary fix. In this view it fails to address the fundamental issue: there simply being too many mouths to feed.

As mentioned in the quote, this suggestion is commonly associated with the name of Thomas Robert Malthus, the English political economist writing at the turn of the nineteenth century. Malthus is famous for the assertion that in the absence of ‘preventative checks’ to reduce birthrates, the natural tendency for populations to increase – being ‘so superior to the power of the earth to produce subsistence for man’ – ultimately results in ‘positive checks’ that increase the death rate. If all else fails to curb population, ‘gigantic inevitable famine stalks in the rear, and with one mighty blow levels the population with the food of the world'.3

But does the evidence support this idea? Here we look into the relationship between population growth and famine, as well as that between population growth and hunger more generally.
Does population growth cause famine?

For our entry on Famines we produced a dataset of the estimated number of deaths from all famines worldwide since the 1860s. The chart below compares the number of deaths per decade with the total world population over the same period.

Looking at the world as whole, it is very difficult to square Malthus' hypothesis with the simple but stark fact that, despite the world population increasing from less than one billion in 1800 to more than seven billion today, the number of people dying due to famine in recent decades is only a tiny fraction of that in previous eras.
Famine victims by decade and world population, 1860s-2010s



We might naturally think that the explanation for this trend lies in increasing agricultural production. Indeed, food supply per person has consistently increased in recent decades, the large increase in global population being met with an even greater increase in food supply (largely due to increases in yields per hectare).
Food supply by region in kilocalories per person per day, 1961-2013Daily per capita food supply by world region, measured on the basis of average caloric supply (kilocalories per person per day).Note that this measures the food available for consumption at the household level but does not account for any food wasted ornot eaten at the consumption level.1961197019801990200020130 kcal500 kcal1,000 kcal1,500 kcal2,000 kcal2,500 kcal3,000 kcal3,500 kcalNorthern AmericaEuropeOceaniaSouth AmericaWorldAsiaAfricaSource: Daily caloric supply per capita long-term - FAO (2017)

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However, looking at the issue in this way is too simple. As we discuss in our entry on Famines, insufficient aggregate food supply per person is just one factor that can bring about famine mortality. Contemporary famine scholarship tends to suggest that insufficient aggregate food supply is less important than one might think, and instead emphasises the role of public policy and violence: in most famines of the 20th and 21st centuries, conflict, political oppression, corruption, or gross economic mismanagement on the part of dictatorships or colonial regimes played a key role.4 The same also applies for the most acutely food-insecure countries today.5It is also true of the 2011 famine in Somalia referred to above, in which food aid was greatly restricted, and in some cases diverted, by militant Islamist group al Shabaab and other armed opposition groups in the country.6

Famine scholar Stephen Devereux of the Institute of Development Studies, University of Sussex, summarizes the trajectory of famines over the 20th century as follows: "The achievement of a global capacity to guarantee food security was accompanied by a simultaneous expansion of the capacity of governments to inflict lethal policies, including genocidal policies often involving the extraction of food from the poor and denial of food to the starving."7

Thus, all in all, the recent history of famine mortality does not fit the Malthusian narrative particularly well. Firstly, contrary to what Malthus predicted for rapidly increasing populations, food supply per person has – in all regions – increased as populations have grown. Secondly, famines have not become more, but less frequent. Thirdly, in the modern era the occurrence of major famine mortality, and its prevention, is something for which politics and policy seem the more salient triggers.
Does population growth increase hunger?

Famines tend to be thought of as acute periods of crisis, and are in that sense to be distinguished from more chronic manifestations of hunger that may in some places represent 'normal' circumstances, despite being responsible for large numbers of deaths.8 Given the typically political nature of outbreaks of such famine crises, it may make more sense to look for an effect of population growth on the longer-term trends of hunger and malnutrition.

But again, at the global level, we know that population growth has been accompanied by a downward trend in hunger. As we discuss in our entry on Hunger and Undernourishment, in recent decades the proportion of undernourished people in the world has fallen, and, although more muted, this fall is also seen in the absolute number. The number of people dying globally due to insufficient calorie or protein intake has also fallen, from almost half a million in the 1990s to roughly 300,000 in the most recent data, as shown in the visualisation below.
Protein-energy malnutrition deaths by age, WorldAnnual number of deaths from protein-energy malnutrition (which results from insufficient caloric and protein intake) by age groupacross both sexes.1990199520002005201020160100,000200,000300,000400,000500,00070+ years old50-69 years old15-49 years old5-14 years oldUnder-5sSource: IHME, Global Burden of Disease (GBD)

We can also look at the experiences of individual countries, rather than just at the global level. Do those countries with particularly high population growth rates find it harder to adequately feed its population?

In order to get some idea about this, we can compare countries' Global Hunger Index (GHI) score with their population growth rates. GHI is a composite measure, out of 100, that combines four indicators: undernourishment, child wasting, child stunting, and child mortality.9The first scoring was conducted in 1992, and was then repeated every eight years with the most recent being in carried out in 2017. The score is based on data collected in the years leading up to the scoring year, and as such reflect the hunger levels in this period rather than solely capturing conditions in the year itself. The graphs below show all the countries for which there was GHI data available between 1992 and 2017.10 Crucially, this excludes a number of very food-insecure countries including the Democratic Republic of Congo, South Sudan and Somalia, which have also seen high levels of population growth.11 This should be borne in mind when interpreting the following results.

Of the countries for which we do have GHI data, it is clear that those with higher levels of hunger have also tended to have had higher population growth over the last 25 years.12
Global Hunger Index in 2017 vs. Population growth 1992-2015 (UN PopulationDivision)Population growth 1992-2015 (UN Population Division)-20%0%20%40%60%80%100%120%140%Global Hunger Index in 2017 (Global Hunger Index 2017)01020304050ChinaIndiaIndonesiaBrazilPakistanNigeriaBangladeshRussiaMexicoPhilippinesVietnamEthiopiaEgyptIranTurkeySouth AfricaTanzaniaUkraineKenyaAlgeriaUgandaSudanIraqAfghanistanMoroccoMalaysiaSaudi ArabiaGhanaMozambiqueNorth KoreaMadagascarSri LankaRomaniaChileKazakhstanCambodiaSenegalChadRwandaCubaGuineaBoliviaHondurasTajikistanJordanSierra LeoneCosta RicaCentral African RepublicLiberiaCongoLebanonGeorgiaAlbaniaKuwaitOmanJamaicaLatviaBotswanaGambiaGabonMauritiusDjiboutiGuyanaTimorYemenAfricaAsiaEuropeNorth AmericaOceaniaSouth AmericaSource: IFPRI 2017 Global Hunger Index, UN Population Division (2015)

It is important to see though that among the countries for which we have GHI scores in both 1992 and 2017, the level of hunger went down in all but one (Iraq). Over the same period population went up in almost every case. Moreover, those countries that experienced higher levels of population growth in fact saw a bigger drop in their GHI score over this period.13
Change in Global Hunger Index, 1992-2017 vs. Population growth 1992-2015 (UNPopulation Division)Population growth 1992-2015 (UN Population Division)0%20%40%60%80%100%120%140%Change in Global Hunger Index, 1992-2017 (Global Hunger Index 2017)-30-25-20-15-10-50ChinaIndiaBrazilPakistanNigeriaBangladeshMexicoVietnamEgyptTurkeyThailandSouth AfricaTanzaniaMyanmarKenyaArgentinaUgandaIraqAfghanistanMoroccoNepalVenezuelaPeruSaudi ArabiaGhanaMozambiqueNorth KoreaMadagascarSri LankaRomaniaBurkina FasoNigerMaliMalawiGuatemalaEcuadorCambodiaZambiaChadCubaGuineaHaitiHondurasBulgariaJordanLaosEl SalvadorNicaraguaLebanonPanamaAlbaniaKuwaitBotswanaGambiaGuinea-BissauDjiboutiYemenAfricaAsiaEuropeNorth AmericaOceaniaSouth AmericaSource: IFPRI 2017 Global Hunger Index, UN Population Division (2015)Note: Downwards sloping line is line of best fit (predicted values from a linear regression)

The countries that saw high population growth over this period started with higher levels of hunger in 1992. So what we are seeing here is that countries are converging towards lower levels of hunger: it fell quickest in countries with the highest levels of hunger, as we can see in the chart below.
Change in Global Hunger Index, 1992-2017 vs. Global Hunger Index in 1992Global Hunger Index in 1992102030405060Change in Global Hunger Index, 1992-2017 (Global Hunger Index 2017)-30-25-20-15-10-50ChinaIndiaIndonesiaBrazilPakistanNigeriaBangladeshMexicoPhilippinesVietnamEgyptTurkeyThailandMyanmarKenyaArgentinaAlgeriaIraqAfghanistanNepalVenezuelaPeruMalaysiaGhanaNorth KoreaMadagascarSri LankaRomaniaAngolaBurkina FasoChileNigerMalawiGuatemalaEcuadorZambiaSenegalZimbabweChadRwandaCubaGuineaDominican RepublicLaosTogoNicaraguaCentral African RepublicCongoPanamaKuwaitLesothoGabonDjiboutiYemenAfricaAsiaEuropeNorth AmericaOceaniaSouth AmericaSource: IFPRI 2017 Global Hunger Index

So whilst countries that experience hunger do tend to have high levels of population growth, the idea that population growth necessarily leads to increased hunger is clearly mistaken: many countries with high population growth have recently managed to decrease levels of hunger substantially.
Conclusions

Environmental degradation, including climate change, does pose a threat to food security, and the growth of human populations has undoubtedly exacerbated many environmental pressures. However, this represents only one aspect of the complex explanation of why so many people suffer and die from undernourishment today, despite their being adequate food available for consumption globally.14

'Malthusian' explanations of famine and hunger thus fall short for the following reasons, the evidence for which we reviewed above:
Per capita food supply has increased as populations have grown, largely due to increasing yields.
Famine deaths have decreased, not increased, with population growth.
Food scarcity has played a smaller role in famines than suggested by the Malthusian narrative. It ignores other factors like conflict, poverty, access to markets, healthcare systems, and political institutions.
Population growth is high where hunger is high, but that does not mean that population growth makes hunger inevitable. On the contrary, we see that hunger has fallen fastest in countries with high population growth.

If we want to put an end to hunger, we need to understand the diverse causes that bring it about. Oversimplifications that mistakenly see hunger and famine as an inevitable consequence of population growth do not contribute to this end.
Footnotes


Who would have thought it? Population growth and famine would appear to be linked! Blog entry from www.jonathanporritt.com, dated 11/07/2011. Accessed 19 Jan 2018. Emphasis added.


The excess mortality estimate is taken from the World Peace Foundation list of famines.


Malthus T.R. 1798. An Essay on the Principle of Population. Chapter VII, p 44.


See, for instance, de Waal, A. The end of famine? Prospects for the elimination of mass starvation by political action, Political Geography, 62:2008


The threat of famine in Yemen, South Sudan and Nigeria are all the direct consequence of conflict, and the drought in Somalia arrives after decades of conflict and political instability. See FEWS.net for more details.


Seal, A., & Bailey, R. (2013). The 2011 Famine in Somalia: lessons learnt from a failed response? Conflict and Health, 7, 22. http://doi.org/10.1186/1752-1505-7-22. As the authors note, this was in part due to concern on the part of humanitarian organisations that they would be contravening US government sanctions. Furthermore, both the US and the EU had significantly reduced humanitarian spending in the country in the run up to the famine.


Devereux, S. Famine in the Twentieth Century. IDS working paper 105, 2000.


de Waal, 2018 defines famine as 'a crisis of mass hunger that causes elevated mortality over a specific period of time'. Note that the official IPC classification system used by the UN for famine declarations just looks at total (undernourishment-related) death rates in absolute terms, rather than relative to any non-crisis reference level. This contrasts somewhat to the typical ex-ante famine assessment in which excess mortality is estimated by factoring out the counterfactual death rate – however high.


More information on these individual indicators, including their definitions, can be found on our entry on Hunger and Undernourishment.


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These three countries would be situated in the top quarter of our sample in terms of population growth, with DRC and South Sudan roughly in the top decile.


Statistically significant at the 1% level, even when controlling for GDP per capita in 2016 (using World Bank PPP data)


This relationship is significant at the 1% level. The relationship is stronger (both in magnitude and significance) controlling for GDP per capita (using World Bank PPP data)


World food supply per person is higher than the Average Dietary Energy Requirements of all countries. See our entry on Food per Person for more details.

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