Thousands of people in the drought-stricken island nation have been affected by famine, and more than a million others are considered to be in a food security crisis or emergency.
Nearly 30,000 people in Madagascar are in the grips of the world's only famine, driven by climate change, amid "heartbreaking" scenes of children wasting away.
The UN's World Food Programme said on Tuesday that more than 27,800 people were now officially affected by famine in the country, and more than 1.3 million others were considered to be in a food security crisis or emergency.
"This is basically the only... climate change famine on Earth," told Arduino Mangoni, WFP's deputy country director in Madagascar.
But he warned that "given the trends", climate change may provoke other famines in the world.
"We're seeing signs of that everywhere."
'Children are really skin and bones'
Mangoni said the situation in Madagascar was particularly "alarming".
The island nation off southeastern Africa has been hit by its worst drought in four decades, brought on by global warming.
He described a recent visit to a nutrition centre filled with silent, staring children "who were really skin and bones".
He added that Madagascar has only just entered its usual "lean season", and faces another six months before the next harvest, if it comes in.
"The situation between now and in March-April, when the harvest is expected, cannot but further deteriorate," Mangoni warned, stressing the need to urgently increase assistance.
WFP said it immediately needed $69 million to provide emergency life-saving aid over the next six months.