Human-induced climate change can aggravate the conditions which cause wildfires, and increase their likelihood, according to a review of studies which suggests limiting global warming below two degree Celsius may help reduce some of the effects. Researchers, including those from the University of East Anglia in the UK, conducted a review of 57 peer-reviewed papers published since the Fifth Assessment Report by The Intergovernmental Panel on Climate Change (IPCC) was published in 2013.
The findings, according to the scientists, show associations between climate change and increased frequency or severity of fire weather. These are periods with a high fire risk due to a combination of high temperatures, low humidity, low rainfall, and often high winds with anomalies in a few regions, they said in a statement.
They said rising global temperatures, more frequent heatwaves, and related droughts may increase the likelihood of wildfires in some regions by creating hot and dry conditions. This may promote fire weather, which can be used as an overall measure of the impact of climate change on the risk of fires occurring, the researchers added.
Based on the review, the scientists said fire weather seasons have lengthened in about a quarter of the Earth's vegetated surface, leading to about a 20 per cent increase in global mean length of the fire weather season.
"Overall, the 57 papers reviewed clearly show human-induced warming has already led to a global increase in the frequency and severity of fire weather, increasing the risks of wildfire," said Matthew Jones from UEA, one of the scientists who wrote the review. "This has been seen in many regions, including the western US and Canada, southern Europe, Scandinavia, and Amazonia. Human-induced warming is also increasing fire risks in other regions, including Siberia and Australia," Jones said.
There is also evidence that humans have significant potential to control how this fire risk translates into fire activity, the scientists said.
This is particularly through land management decisions and ignition sources, Jones said.
"Fire weather does occur naturally but is becoming more severe and widespread due to climate change. Limiting global warming to well below two degree Celsius would help avoid further increases in the risk of extreme fire weather," said co-author Richard Betts from the University of Exeter in the UK.
"Wildfires can't be prevented, and the risks are increasing because of climate change. This makes it urgent to consider ways of reducing the risks to people. Land planning should take the increasing risk in fire weather into account," Iain Colin Prentice, co-author from Imperial College London in the UK, said.