Climate change could leave Latin American and Caribbean countries with a $100bn annual bill by 2050 if the average rise in global temperatures cannot be contained below 2°C.

Although the region accounts for only 11 per cent of global emissions it is likely to be disproportionately affected by rising temperature, a report commissioned by the Inter-American Development Bank (IDB) said yesterday ahead of the forthcoming Rio+20 summit.

It highlighted the loss of coral reefs, melting glaciers and damage to the Amazon basin as the most pressing concerns should the international community be unable to prevent warming above the level most scientists recognise as the point at which the worst effects of climate change are unavoidable.

The net loss of agricultural exports alone would be between $30bn and $52bn in 2050, the report said, adding “losses of this magnitude would limit development options as well as access to natural resources and ecosystem services”.

In contrast, the cost of helping countries adapt to climate change would be dwarfed by the price of taking no action and dealing with the damage, the bank said.

It estimates around 0.2 per cent of GDP for the region, or about 10 per cent of the costs of physical impacts, would be needed to support climate adaptation.

Much work has already been done to reduce emissions from deforestation, which has helped cut the region’s greenhouse output 11 per cent from 2000 to 2010.

But the IDB says this needs to be increased to balance out expanding transport and power production sectors, which together could add two billion metric tons of CO2 per year, pushing total greenhouse gas emissions in the region to seven billion metric tonnes by 2050 – equivalent to 9.3 metric tonnes per capita.

This would be almost five times the IDB’s recommendation for the region of no more than 2.2 metric tonnes emissions per capita, a target that it says would require investment of around $110bn per year, or 0.6 per cent of projected Latin American GDP in 2050.

“Yes, spending $110bn a year for a region that faces major development challenges is not an easy proposition,” said Pablo Gutman, director of environmental Economics at campaign group WWF, which helped produce the paper.

“However, this would also bring about major benefits such as improved food and energy security; people would have healthier lives in cleaner environments. In the long term this is the surest way to ensure Latin America and the Caribbean continues to prosper along a sustainable path.”