In 1981, writing about the great famines of the last century, Nobel laureate Amartya Sen noted that droughts are natural phenomena, but famines are man-made.
In the intervening years, many countries have successfully prevented drought from leading to famine, while others have not.
Today, we are again seeing famine in the Horn of Africa, in Somalia, during the most severe drought in 60 years.
So far, there is no famine in Ethiopia or Kenya - countries that are also experiencing the drought.
But famine is declared only when two in 10 households have no food, three in 10 children are malnourished, and four in 10,000 children die each day.
There can be a lot of suffering and death before these dreadful technical thresholds are met. This is what we are seeing today in Kenya's arid and semi-arid lands in the north and east of the country.
In May, a mid-season assessment found that failure of the long rains would leave up to 3.5 million people in these arid lands needing food aid.
Five very large rural counties - Garissa, Isiolo, Mandera, Marsabit and Wajir - are already food-insecure.
In addition, Kenya is hosting the world's largest refugee camp, Dadaab, which I visited last week.
Every day, 1,300 Somalis reach the camp, seeking refuge from insecurity and climate change. Dadaab now has about 400,000 Somalis as well as a large Kenyan host community, making it Kenya's third largest city.
As an established camp, Dadaab is well-organised to receive government and international assistance, including food, water and healthcare.
Even so, rapidly increasing numbers are overwhelming current capacities and seriously straining the environment - which was already fragile before this growing population arrived.
Moreover, many of the most recent arrivals, particularly the very young and the very old, are in terrible condition and need extra help.
Still, they may be among the lucky ones. Others have not been able to make the arduous journey and are slowly dying of hunger or disease.
In Kenya, the government and its development partners, including the World Bank, are responding.
On May 30, President Kibaki declared a national disaster and suspended the tariff on maize import, thus encouraging more imports and also exerting downward pressure on Kenya's maize prices, which have doubled since December and are again exceeding international prices.
As Kenya has a structural food deficit due to its limited arable land and its growing population, the tariff should be removed permanently.
On July 14, the Cabinet permitted millers to import genetically-modified maize for production into flour and also approved Sh8 billion to provide emergency assistance in response to the drought.
These funds are being used to double the government's food distribution, repair boreholes, truck water where needed, treat and offtake livestock, provide nutritional supplements, and support the school feeding programme - which has been a critical lifeline to many of the poorest children in areas hard-hit by drought.
The World Bank is not a humanitarian agency, but we are doing our part. Under the Orphans and Vulnerable Children programme, we are supporting a rise in the cash transfer being provided to beneficiary households to help them to manage rising food prices.
Working with the government and other partners, we developed an Early Warning System that improved drought response through bulletins, rapid food security assessments and community feedback meetings.
The impact of these activities is considerable. During the droughts of 2004/5 and 2009, the proportion of people needing food aid fell by 40 per cent in arid districts compared to the drought of 2000/1.
But more can and should be done to improve the resilience of the poor to drought and climate-change. This is where the World Bank can help.
We are working with the government to identify and finance a large project to safeguard water security in specified water-scare areas in Kenya, including Nairobi, which has not expanded water storage since the Bank helped to build the Ndakaini reservoir in the early 1990s.
Mr Zutt is the World Bank's country director for Eritrea, Kenya, Rwanda and Somalia.