16. Number of Outdoor Fires
JP Palutikof

Number of outdoor fires in England and Wales each year shown in relation to rainfall in England and Wales in June, July and August

Specific indicator
Local Authority fire services are required to report all fires to the Home Office. The specific indicator selected is the number of secondary (outdoor) fires in each year in England and Wales.
[Source: Home Office Statistical Bulletin, Home Office, Dissemination Unit, Apollo House, 36 Wellesley Rd., Croydon CR9 3RR]

Relevance
Secondary fires, as defined by the Home Office, are those which involve grassland, straw and stubble, refuse and refuse containers, derelict buildings and vehicles, and outdoor structures. They are therefore exactly those fires which should be affected by climate variability and change. However, they are relatively minor. By definition, they should not involve casualties, rescues or escapes, and should not have been attended by more than four appliances. As such, their chief economic importance lies in the cost to the fire service: each of these fires must be attended and dealt with.

Sensitivity to climatic and other factors
Many fires occur every year regardless of the weather. But clearly, additional outdoor fires occur in hot, dry conditions. In Britain, very few outdoor fires are due to natural events such as lightning strikes. Almost all are caused by the actions of people, either carelessly or deliberately setting fires. People are more likely to be outdoors in hot, dry conditions. Also, such weather is conducive for the spread of fires, necessitating attendance by the fire services when, in wetter or cooler conditions, the fire would be naturally extinguished.

The annual number of outdoor fires in England and Wales is very closely correlated with rainfall in June-August and summer Central England temperatures.

Change over time
There is a clear upward trend in the annual number of outdoor fires. Superimposed on this, there are fluctuations from year to year, which can be linked to the occurrence of unusually dry or unusually wet summers. Thus, the dry summers of 1989, 1990 and 1995 were marked by very large numbers of outdoor fires, whereas the wet summers of 1985, 1988 and 1992 resulted in relatively few fires over the year as a whole.

Since the 1995 hot dry summer, no extreme summers have been experienced, and rainfall amounts have been unexceptional. In parallel with this, the occurrence of fires has been close to the long-term average. If climate change brings an increased frequency of dry and hot conditions in the summer half-year we would expect the number of fires also to increase. Although people may become more careful with respect to disposal of hazardous materials, this is unlikely to fully offset the trend towards more frequent outdoor fires.