Professor Ray Bates:

The question of how climate extremes are related to greenhouse gases is a very controversial one. It was not predicted by the models that increasing greenhouse gases would lead to an increase in extremes. It surprised us as climate scientists. We expected a global warming and this is what the models predicted. We did not expect a change in extremes. If one looks at the first IPCC report, it did not predict a change in extremes. By the time of the last IPCC report the change in extremes had become visible, or at least there have been very extreme events.

The most extreme weather event in the past 100 years in the world was the Chinese floods in 1931 in which 140,000 people were drowned and as a result of which 4 million people died subsequently because of disease and hunger. The most extreme weather event in Ireland in the past 100 years was the winter of 1947 when there were three months of continued snow and large areas were cut off and during which many people and animals died. The recent IPCC report, "Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation", is very cautious in attributing extreme weather events to a change in the level of greenhouse gases. It states: "In many (but not all) regions over the globe with sufficient data, there is medium confidence that the length or number of warm spells or heat waves has increased". That is a cautious and qualified statement.