Old world order … should CO2 cuts incorporate the principle of historical responsibility? Photograph: HO/Reuters

Scanning through the amount of carbon dioxide that countries put into the atmosphere over the past century might seem even irrelevant to modern climate change debates.

Fatima Ibrahim was having two of her children weighed, measured and fussed over when we found her with 30 other mums and more than 50 hungry kids at an emergency feeding centre in northern Kenya. Barwaco came in at 12.8kg and her brother Mohamed at 8.1, and both were crying lustily as people crowded round Dida Jirma, a young community doctor.

Jirma noted the children’s weights and height and measured the circumference of their left upper arms. Some were ominously quiet and clearly ill, others playful. When it was Fatima’s turn, the doctor dived into a big cardboard box and counted out two dozen silver foil sachets of Plumpy’nut – one of the 21st century’s true superfoods.

Barwaco and Mohamed come from Nana, a small village way up on the stony Kenyan Ethiopian border. But like millions more children around the world, they owe their lives to this brand of food which is never advertised and is unknown outside disaster spots. The sweet paste, invented by a French scientist, is made under licence to UN children’s charity Unesco on an industrial estate outside Le Havre, and its mix of peanut butter, vegetable oils, powdered milk, sugar, vitamins and minerals is the equivalent of royal jelly, açaí berries and chocolate all wrapped into one for malnourished children. It’s cheap – a sachet costs about 85p – and because it needs no cooking or added water, children can safely feed themselves on it at home. In just a few years “ready-to-use therapeutic foods” (RUTF) like Plumpy’nut have revolutionised the treatment of severe malnutrition.