Countries must do more to cut their emissions of greenhouse gases like carbon dioxide and methane, and the potential threats should galvanise more action, said Cox.

"We have to convince these countries that it's in their interest," Cox said in an interview on Wednesday.

The Bank has so far channelled some US$200 million to curb greenhouse gas emissions from the region, for example to cut methane emissions from rubbish dumps.

"We want to get them round the table. If we can sweeten the deal (they'll) commit to working on this issue."

Simply by covering rubbish dumps, project developers can capture emissions of methane gas, a powerful contributor to global warming, and acquire carbon credits to sell to western companies that want to be seen acting on climate change.

Some projects have used these extra revenues to employ people who previously picked through rubbish as a way of life.

The next step would be to scale up such carbon finance to cover entire national economic sectors, like steel and power, and to advise Brazil and Mexico on how to convert their economies to a low-carbon energy path, said Cox.

Burning forests is another big source of carbon emissions, and the Bank wants to advise Brazil on how to use the Amazon rainforest sustainably, for example by clarifying land ownership rights among indigenous peoples.

"The Amazon can be a touchy subject for Brazil. We're not saying protect the whole Amazon," Cox said.

"We're not talking about a vast zoological park. We're working on a number of issues, 25 million people live there, how do they get jobs, issues of infrastructure and building roads."

Cox was in London to give British government officials the results of the Bank's last "flagship report" from the region, on the issue of unregistered workers missing out on state benefits. Climate change will be the topic this year.

She said the impact of global warming was also appearing.

"We estimate Ecuador will have to spend US$100 million over the next 20 years developing new water supplies," she said, referring to Quito's dependence on retreating glaciers.

In Colombia, malaria has appeared for the first time 2,000 metres above sea level, implying greater health costs, she said.