With around one billion people — one-seventh of the world’s population — now living in chronic hunger and another billion not receiving adequate nutrition, fears are growing among world policy makers of the consequences of rapid food price rises this year.

With severe crop failures in the United States and India already starting to drive up the prices of wheat and maize world-wide, UK Premier David Cameron has called a “hunger summit” this week to address the unfolding crisis.

UK aid agencies who last week geared up for a new emergency appeal on behalf of the drought hit countries of the Sahel across a swathe of central sub Saharan Africa, have welcomed the move but warned more must be done.

Oxfam GB chief executive Barbara Stocking called the summit “a positive step forward,” but stressed: “It must be the start of concerted action to address the shocking fact that while we produce enough food to feed everyone on the planet, about a billion will tonight go to bed hungry.

“Dwindling natural resources and the gathering pace of climate change mean that without urgent action, things will only get worse, and multiple major crises could quickly move from being an exception to being the norm.”

Save the Children chief executive Justin Forsyth said the Sahel region of Africa was in a “permanent food crisis.” He added: “It is lurching from one crisis to the next. One bad year tips families over the edge, and the world responds to the emergency, but this is the tip of the iceberg. Below the surface, there is a huge ongoing crisis we don’t address.”

The aid groups’ warnings come amid even more troubling news as droughts in the United States, India, and elsewhere which are driving a spike in the price of corn and other cereal grains, which experts warn could create conditions similar to the food crisis of 2008, when dramatic shortages and price increases sent fragile economies into turmoil.

Investment analyst Jeremy Grantham said the world was heading into a “chronic food crisis that could unfold over the next forty years” and predicted that the ongoing droughts would “threaten poor countries with increased malnutrition and starvation and even collapse,” and that “resource squabbles and waves of food-induced migration will threaten global stability and global growth.”

Experts say there are a number of simple measures that could help address the crisis including eliminating food waste — about one-third of food is thrown away in rich countries and an even higher proportion in the poorest, for different reasons — and doubling the productivity of smallholdings.

Other measures include increased investment in small farmers, greater transparency in commodity markets and an end to biofuel subsidies.

However, Britain’s Department for International Development which is hosting the summit acknowledged that generating the political will and leadership to address malnutrition is a huge challenge.

Experts note that for the first time in recent history, aid agencies have had to respond to three serious food crises – the Sahel, Yemen and East Africa – in the past 12 months.