A report published by Save the Children and Oxfam said the death toll could have been lessened if early and quick action had been taken by the international community, donor governments and humanitarian agencies when confronted with clear warning signs a disaster was in the making.
Figures collected by the British Department for International Development said between 50,000 and 100,000 people died in the 2011 crisis that affected Somalia, Ethiopia and Kenya, The Guardian newspaper reported.
The report suggests human factors turned the already dangerous drought conditions into a disaster.
"A culture of risk aversion caused a six-month delay in the large-scale aid effort because humanitarian agencies and national governments were too slow to scale up their response to the crisis," the report said, "and many donors wanted proof of a humanitarian catastrophe before acting to prevent one."
"Waiting for a situation to reach crisis point before responding is the wrong way to address chronic vulnerability and recurrent drought in places like the Horn of Africa," the report said in recommending improved risk-reduction strategies, greater funding flexibility and preventative humanitarian work.
"All actors and early warning specialists need to develop a common approach to triggers for early action," it said.