Pakistan, Guatemala and Colombia topped the league table in 2010 for countries that were worst hit by extreme weather events, according to a "climate risk index" published here on Tuesday.

But over a 20-year span, the countries that were most vulnerable were Bangladesh, Myanmar and Honduras, said the report, published on the sidelines of the UN climate talks in Durban.

The index, compiled by a European NGO called Germanwatch, is an annually-published pointer of which countries are most in need of shoring up defences against floods storms, drought and heatwaves, which UN climate scientists say will worsen this century.

It factors in the cost of the event in terms of human lives and absolute losses in dollar terms, but also the relative cost according to the country's level of prosperity.

Pakistan in 2010 was hit by the worst floods in its history, with 84 out of 121 districts affected, Germanwatch said. Guatemala was rocked by hurricanes and flooding struck Colombia.

Russia ranked fourth on the list, after a heatwave in July that caused massive forest and peat fires and led indirectly to 55,000 deaths.

Scientists are loath to pin single weather events to the longer-term trends of climate change.

But Germanwatch, citing a study in the US peer-reviewed journal Proceedings of the National Academy of Sciences (PNAS), said the Russian heatwave could well be considered an exception.

Across the world, more than 710,000 people died from 1991 to 2010 from 14,000 extreme weather events, incurring economic losses in today's terms of more than 2.3 trillion dollars, it said.

When seen across this 20-year period, not a single developed country features in the top 10 for climate risk.

Only one -- Russia -- featured in the top 20, and this was as a result of the 2010 heatwave.

"These results underscore the particular vulnerability of poor countries to climatic risks, despite the fact that the absolute monetary damages are much higher in rich countries," Germanwatch said.