IMAGINE the entire populations of Aberdeen and Dundee gathered together in the open.

Now imagine being given the task of supplying them with enough to eat and drink to keep them alive, possibly for months. That is the task facing the aid agencies at Dadaab in eastern Kenya. It is already the world’s largest refugee camp and every day 1300 or more starving souls straggle in. Some are too far gone to save.

The people at Dadaab, many of whom have trekked for two weeks from war-torn Somalia, represent only a fraction of the estimated 10 million people affected by the severe drought that is once again ravaging the Horn of Africa. As well as Somalia, the rains have failed across large swathes of Djibouti, Ethiopia, Kenya and Southern Sudan, which ought to be celebrating becoming the world’s newest country this week-end.

Aid agencies and the UN have been warning for months of the incipient crisis but, as ever, the world only reacts when it is already too late for some. In Dadaab this week a desperate doctor spoke of the lives of emaciated children “slipping through my hands”. Better late than never. With the offer of £38m in food aid to Ethiopia, Britain has done better than most. And the British public stands ready to respond with its customary generosity. More than £1m had been collected even before the launch yesterday of a joint appeal by the Disasters Emergency Committee.

This process has become wearisomely familiar. As the effects of climate change on this already-barren area become more pronounced, those who suffer most are already-poor people, who emit only a tiny fraction of the billions of tonnes of greenhouse gases belched forth by the rich world. If for no other reason, there is a moral imperative to help them.

In Somalia this natural disaster has been aggravated by 20 years of anarchy. There are nearly 1,500,000 internally displaced people and similar numbers have fled abroad. A succession of western-funded peace conferences have failed to persuade the warring factions to sink their differences. Nevertheless, it is important to keep trying, especially given the country’s burgeoning role as a base for al-Qaeda.

Also, while aid agencies move from one crisis-torn region to another, it is vital that emergency aid is not allowed to detract from long-term development work. They will not prevent natural disasters but projects such as tree planting, digging and maintaining boreholes, and training itinerant vets and health workers, can build a people’s resilience.

In addition, the World Food Programme exists to provide a buffer against emergencies like the current one but it is constantly underfunded. It is time more was done to ensure that rich countries keep their promises to help those in direst need.