It's impossible to point at a single weather event and put it down to climate change. Instead, we talk about probabilities.
Certain extreme weather events have become much more frequent, or more likely to happen in a given year, since the recent onset of climate change. The practice of linking weather events to human-influenced global warming (or something else) is called attribution studies.
An extreme heatwave of the type that occurred in Texas in 2011 (a La Niña year) was calculated to have become much more probable in recent years. What was a 1:100-year likelihood in the 1960s is now thought to have odds of one in six years.
Likewise, the odds of a cold winter in the UK, like that experienced in 2010/2011, were found to have roughly halved. However, not all types of extreme events were found to have a human influence.
Experts predict that fierce storms and floods, such as those that brought chaos to parts of the UK in 2012 and 2013, are likely to become even more frequent in the future. Over the past 100 years, warming has been accompanied by a reduction in the frequency of frosts and an increase in the number of heatwaves in many parts of the world. The amount of rainfall is getting heavier in some countries in terms of volume per downpour.
Since the 1960s, many countries around the world seem to have experienced a reduction in the number of cool days and nights and increases in the number of warm days and nights.
Last updated: 27 September 2013