2010 is likely to be on par with the warmest years on record, and whilst a warmer atmosphere holds more water vapor, La Nina is likely to be the cause of the latest Australian floods.
"Scientists have emphasised that none of the three extreme weather events occurring now can be linked directly to global warming. Two of them, the floods in Australia and Sri Lanka, may be connected with a naturally occurring climatic phenomenon in the Pacific Ocean, called La Niña, whereas the landslides in Brazil are the result of heavy, localised downpours falling on badly constructed homes built precariously on steep hillsides.
It is almost certain that La Niña is behind the Queensland floods. La Niña, which means "little girl", is a change in the Pacific Ocean where a body of relatively cold water wells up over the equatorial region, causing a corresponding build-up of warm water in the western regions near Indonesia and Australia.
This warm water usually dissipates to the east in non-La Niña years. This year, however, is the strongest La Niña since 1974, and the warm water around Australia and Indonesia, with nowhere to escape, has generated heavy rain clouds that have burst over Queensland.
In 1974, when Queensland also suffered heavy flooding, La Niña was stronger then than at any time on record. Sri Lanka remained dry that time, but this time there is evidence that some of the warm moist air has blown further west, just nudging Sri Lanka into torrential downpours, according to Adam Scaife, head of long-range forecasting at the Met Office.
"Rainfall is expected to increase in a warmer world but in this case it's linked with the La Niña cycle. It's a natural cycle and we don't expect it to change in the future. This is not a climate-change issue, it's La Niña, and it's happened before and will happen again," Dr Scaife said.
Equally, the rain around Rio is associated with a typical weather system in the South Atlantic. Here the issue has centred on the lack of urban planning." Independent newspaper.