While climate shocks alone may not trigger new unrest, the Washington-based IMF said, they "significantly worsen conflict, compounding fragility" such as hunger, poverty and displacement.
By 2060, conflict deaths could increase by 8.5% as a share of the population in so-called fragile and conflict-affected states FCS, and by up to 14% in those nations facing an extreme increase in temperatures, the report said.
In all, 39 countries that are home to nearly one billion people and 43% of the world's poor are classified as FCS by the World Bank.
More than half of these nations, which are disproportionately burdened by climate change, are in Africa.
Over 50 million more people in these countries could be driven into hunger by 2060 due to lower food production combined with higher prices, the IMF warned.
Economic losses resulting from climate shocks are more "severe and persistent" in fragile nations than in other countries, it added.
In a separate blog, the IMF said it was vital that leaders gathering next week in Kenya for the first African Climate Summit come up with solutions for vulnerable nations.
"Each year, three times more people are affected by natural disasters in fragile states than in other countries. Disasters in fragile states displace more than twice the share of the population in other countries," the blog said.
The IMF said that by 2040, these nations could face 61 days a year of temperatures above 35 degrees Celsius (95 degrees Fahrenheit) on average — four times more than other countries.
"Extreme heat, along with the more frequent extreme weather events that come with it, will endanger human health and hurt productivity and jobs in key sectors such as agriculture and construction."
The September 4-6 summit in Nairobi aims to address the urgent climate challenges facing the continent of 1.4 billion people and comes ahead of the next round of United Nations climate talks in the United Arab Emirates in November and December.
For years, African governments have been demanding that the world's top polluters pay for the harm their emissions have caused.
"In the lead-up to COP28 in Dubai, it is essential to consider climate and conflict together," International Crisis Group senior analyst Nazanine Moshiri said in a note to AFP ahead of the summit.
"We only need to consider the situation in the Horn of Africa, where climate change and conflict feeds further instability with five consecutive poor rainy seasons, unprecedented floods and the world's worst food emergency," Morishi added.
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