English: As Amartya Sen argued, the fact that there may be enough food available in aggregate within a given area does not necessarily mean that everyone will be able to afford it.23

Food crises are often precipitated by spikes in the price of food relative to wages, or the collapse in the price of assets owned. The latter commonly accompanies famines due to many people all at once trying to sell their assets (for instance their livestock) in order to be able to buy more food. Such shocks can mean that those already living close to the level of subsistence may find their 'exchange entitlement' – that which they can obtain on the market in exchange for their labor or other assets – fails to provide them with enough food, even if the aggregate local supply is sufficient.

Wealthy countries have very few people living in such extreme absolute poverty, both because of higher incomes before tax and benefits, but also due to higher government expenditures and transfers. It is therefore unsurprising that those countries in which famines occur tend to be very poor. Here we show the inflation-adjusted income per capita of each country at the time they experienced a famine, with some reference points on the vertical axis. As you can see, most countries in which a famine took place had, at the time, average incomes less than half of that of the UK at the outset of its industrial revolution. You can see that average incomes in India – a country that historically suffered very heavily from famine – have grown rapidly in recent decades, while the country has been famine-free at the same time. African countries, conversely, have on the whole remained very poor and make up the majority of recent famines.

This relationship proxies for the presence of extreme poverty and also reflects the fact that poorer countries tend to have less adequate facilities like transport infrastructure, sanitation, and healthcare systems that play a key role in preventing or moderating the impacts of food shortages.

Whilst poverty certainly increases the vulnerability of a country, we should be careful not to think of it as the single, or even the most important, cause of famine, given the typically political nature of most outbreaks of famine.