Extreme Weather

Climate change means that the weather is changing over the long-term. One of the most dangerous aspects of this change is that extreme weather events are becoming more frequent and intense. Storms, heavy rains, heatwaves, droughts and cyclones are all likely to increase over the next hundred years, with associated problems such as floods, reduced food production and harm to human health.

Scientists have predicted that climate change will increase these extreme weather events in the future, but many people are already living with extreme weather events as a result of global warming.

Climate change has already influenced a number of extreme weather events. Different areas of the world experience different forms of extreme weather, with droughts and heatwaves in Africa, Europe and Australia, tropical storms in Asia and the Pacific and cyclones in Australia and the USA.

Hurricane Katrina, the cyclone that devastated New Orleans in 2005, formed when the waters in the Gulf of Mexico were unusually warm – about 2 degrees Celsius warmer than normal for the time of year. This higher ocean temperature helped transform Katrina from a tropical storm to a category 5 hurricane with catastrophic results.

Although there are few models that predict future changes to tropical cyclones, some scientists predict that an average rise of 1 C in sea surface temperature could increase the occurrence of strong storms by a third in the future, and several studies show a link between higher ocean temperatures and more frequent tropical cyclones since the 1970s . That means that extreme cyclones like Katrina are much more likely as a result of climate change.

The UK has also experienced the impacts of climate change on the weather. In 2000, England and Wales experienced the wettest Autumn since records began in 1766. The resultant floods damaged around ten thousand properties, disrupted services severely and caused insured losses of roughly £1.3 billion. Scientific models showed that climate change increased the risk of flooding by 20-90%.

Climate change has also been linked with many other natural disasters, although it is always difficult to pinpoint just how much global warming contributed to any one weather event.

Nevertheless, scientists are confident that climate change is increasing the frequency and intensity of extreme weather events on average.

Extreme weather events damage infrastructure, harm human health and cause millions of dollars in economic loss. Because climate change is already happening, it is important to put in place adaptation measures that reduce the impact of extreme weather events in vulnerable areas and communities.


Seung-Ki Min, Xuebin Zhang, Francis W. Zwiers & Gabriele C. Hegerl, ‘Human Contribution to More Intense Precipitation Extremes‘, Nature, 17 February 2011.

Ian Ammison, et. al., ’The Copenhagen Diagnosis: Updating the world on the latest climate science’, Elsevier, 2011, p. 10., World Disasters Report 2009, Red Cross and Red Cresent, p.100.

Robert Leben, George Born and Jim Scott, ‘CU-Boulder Researchers Chart Katrina’s Growth In Gulf Of Mexico’, University of Colorado at Boulder, 15 September 2005.

Ian Ammison, et. al., ‘The Copenhagen Diagnosis: Updating the world on the latest climate science’, Elsevier, 2011, p. 17.

Richard Black, ‘Warming Boosts Stronger Storms’, BBC News, 3 September 2008.

Pardeep Pall, Tolu Aina, Dáithí A. Stone, Peter A. Stott, Toru Nozawa, Arno G. J. Hilberts, Dag Lohmann and Myles R. Allen, ‘Anthropogenic greenhouse gas contribution to flood risk in England and Wales in autumn 2000‘, Nature, 17 February 2011.