North Korea's food crisis dates back well over a decade. It has diverse roots:

• As the hillier half of a mountainous peninsula, North Korea is economically unsuitable for farming. Pyongyang has sought self-reliance in food for political reasons.
• The late leader Kim Il-sung's order to grow rice and (mostly) maize, at the expense of other crops, began to lower the range and quality of the local diet from the 1980s.
• Yield growth achieved by industrialised farming collapsed after Moscow stopped aid in 1991.
• Floods in and since 1995 saw marginal hillside terraces washed away and the ruin of good farmland downstream.

A growing international aid effort from 1995 failed to prevent a famine in 1996-98, which probably took a million lives out of the 23 million population. Malnutrition remains endemic, affecting 37% of young children. Besides the floods, several new pressures are now squeezing food supplies:

• In 2006, North Korea told the WFP to cut its operation, apparently believing it could get by on lightly monitored food aid from China and South Korea. Persistent claims that grain is diverted to the military are now confirmed; South Korea says border guards have seen this.
• Food aid has fallen since North Korea's nuclear test in 2006. Pyongyang has not asked this year for its usual fertiliser and rice aid from Seoul. It has been strongly critical of Seoul's new right-wing government, even though President Lee Myung-bak has said he exempts humanitarian assistance from his plan to link future cooperation to North Korea's nuclear compliance.
• Even if donors were still minded to help, the recent surge in global grain and fertiliser prices would render supplies costly and hard to source.  
• Spring is always the leanest season, before the new year's harvest is in.