The unprecedented destruction caused by grass fires in the UK鈥檚 recent 40掳C (104掳F) heatwave was made possible by weather conditions that were the most conducive to wildfires in modern records, according to data shared with 快猫短视频.
On 19 July, the UK recorded its hottest ever day, with temperatures peaking at 40.3掳C (104.5掳F) in Coningsby, Lincolnshire, which scientists have established was made far more likely because of climate change. That same day, a series of fires erupted on grasslands on the edges of villages, towns and cities, destroying .
Now, researchers have found that the stage for those fires was set by a 鈥渇ire weather index鈥�, which estimates how conducive weather conditions are for wildfires, reaching its highest ever level on 19 July. The data set for the index goes back 20 years.
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Although the area burned on the hottest day wasn鈥檛 the largest on record, the blazes were the most destructive wildfires the UK has ever seen, in terms of loss of property. 鈥淚t鈥檚 undeniable that this was the most extreme fire weather index that we鈥檇 seen in the UK and we saw the most extreme fires,鈥� says at the London School of Economics.
鈥淭o us in the science community, this was a turning point. It鈥檚 really, really shocking,鈥� says Smith of the destruction caused by the fires.
The fire weather index is built on short and long-term weather data 鈥� including temperature, humidity and rainfall 鈥� to determine the flammability of fuel, including trees and grass.
The area burned by wildfires in the UK this year is the second highest on record, at just over 20,000 hectares, according to data from the European Forest Fire Information System. Only 2019, when large fires blazed on heathlands during the more typical spring fire season, saw a larger area burned. However, 2022 has seen 149 fires so far, compared with the 111 detected by satellites throughout 2019.
July was the driest month in England since 1935, . Smith, part of the , said that researchers out in the field measuring moisture across July reported that levels were impossible to measure in places because they were so low.
According to anecdotal reports by those researchers, few people were spotted out in the UK鈥檚 heathlands on 19 July following a 鈥渞ed warning鈥� that encouraged people to avoid the extreme heat. Heathlands are where most of the UK鈥檚 wildfires usually take place, but there were none on 19 July. All the fires were on grass and arable fields instead.
Smith and his colleagues think many people were avoiding the heat out in the heathlands, sheltering instead near homes and gardens. 鈥淚 think it could have been a lot worse on those days, because people were just not out there in the environment,鈥� he says.
However, that shift in behaviour appears to be linked to the more destructive fires. There is evidence that some of the grass fires started in domestic gardens, spread out into fields and then back into other properties, says Smith. Once ignited, the weather conditions were ideal for fires to develop. Virtually all fires in the UK are ignited by humans rather than natural causes such as lightning.
Smith says fires such as those seen last month weren't expected for another 10 to 15 years, based on previous climate change estimates. 鈥淭hat window of opportunity is clearly gone. Therefore the action needs to be urgent,鈥� he says. As well as action by authorities, he says people need to look at the vegetation surrounding their homes and think about how they can mitigate the risk, down to measures as simple as removing highly flammable dead moss from gutters.
