Oil and gas-producing countries, including several in Africa, face a multi-trillion-dollar hole in their government revenue as the world cuts back on fossil fuels, according to a report by the think-tank Carbon Tracker.
It estimates the cumulative total revenue loss by 2040 will be $13 trillion (in 2020 dollars).
For seven countries, including Angola, Equatorial Guinea and South Sudan, the predicted loss is at least 40%.
For another 12, including Algeria, Chad, Congo, Gabon, Libya and Nigeria, it is in the range of 20% to 40%.
The report – Beyond Petrostates – noted that several countries facing falling revenues had large populations, singling out Nigeria with 206 million, Algeria with 43 million and Angola with 33 million.
The report suggests that these countries should be helped to diversify their economies and reduce dependence on fossil fuels.
Such assistance would reduce the risk of instability and social unrest, as well as help to curb rising temperatures, it says.