Is Global Warming the Culprit?

There is endless debate about whether AGW (Anthropogenic Global Warming) is the culprit in recent extreme weather events such as floods. The floods season is still in full swing in Australia, with Carnarvon inundated for the third time in three months.

Two recent contributions to the controversy add fuel to the fire (oops! mixed disaster metaphor not to mention cliche).

The Climate Action Centre ‘supports community climate action groups and climate activists in Victoria’. They draw on earlier research from CSIRO, Australia’s premier science organisation, to link floods and climate change:

Is there any relationship between the massive Queensland floods and global warming? Scientific opinion seems to be that warmer sea surface temperatures due to climate change (and hence more water vapour in the air), as well as a very strong La Nina with warmer waters off eastern and northern Australia, are both likely contributors to the record flooding. …The climate of 2040 is likely to bring more intense and more frequent extreme rainfall events to coastal eastern Australia, according to a CSIRO climate expert.
Extreme floods and climate change

At Reuters, Gerard Wynn highlights two studies published in Nature:

Man-made greenhouse gas emissions are linked to more frequent heavy rainfall, two studies published found on Wednesday, portraying a clearer human fingerprint after a spate of floods around the world.

Scientists agree that greenhouse gas emissions are warming the world and expect that in turn would lead in the future to more evaporation of water, more moist air and heavier rainfall.

But the two new papers were the first to pin an increase in heavy rainfall in the second half of the last century directly on climate change, as well as one particular extreme flood in Britain.
Floods linked to manmade climate change: studies

At Climate Central, Science journalist Alyson Kenward reports on the same studies:

Until recently, there’s been little evidence that climate change is responsible for the growing number of intense rainfall events seen in many regions, but new research now shows there is a clear connection between some heavy rainfall events and increasing levels of climate-warming greenhouse gases in the air.

There is a note of caution for those who jump from the general to the particular:

While Zhang’s study provides evidence that the global trend towards heavier rainfalls is in part due to higher concentrations of greenhouse gases, it doesn’t mean that manmade climate change is responsible for specific weather events, like the heavy rains that caused the recent floods in Australia.
Scientists Identify Human Connection to Precipitation Extremes

Record high country temperatures

Also at Climate Central a graphic showing the countries that set new record high temperatures in 2010:

Ask a climate scientist

Not sure about the Science? Ask a climate scientist:

With the huge amounts of extreme weather and rainfall in Australian this year, it seemed appropriate to ask questions about rainfall and water vapor in relation to climate science. What areas of the plan will receive more rainfall as climate change continues and will this offset the desertification in other areas? Do water vapor emissions need to be reduced?

Got a question about climate science? Crikey’s environment blog Rooted is still running the Ask a climate scientist series.
Ask a climate scientist: rainfall and water vapor