The risk of catastrophic wildfires is growing around the world as climate change fuels sizzling, tinder-dry conditions, increasing the need for fire-prone countries to adopt preventative measures, scientists warned Wednesday.
Smart, proactive policies - such as setting fires at the end of rainy periods to reduce blazes during hot, dry spells - could help reduce the danger, they said in a report for the U.N. Environment Programme (UNEP).
Here's why wildfires are a growing threat - and how the world can better adapt to changing risks:
Why are wildfire threats growing so significantly?
The size and destructive capacity of wildfires - whether started on purpose, accidentally or by natural phenomena such as lightning - depends largely on the weather and how much fuel is available to burn, as well as where the fire breaks out.
As climate change brings more extreme weather, the risks are growing, scientists say.
"The heating of the planet is turning landscapes into tinderboxes, while more extreme weather means stronger, hotter, drier winds to fan the flames," the report warned.
That means "uncontrollable and devastating wildfires are becoming an expected part of our seasonal calendars".
In some countries, setting intentional fires to clear undergrowth is also becoming harder as homes expand into wooded fire-risk areas or as fire-suppression policies are favoured, meaning the amount of fuel available to fires is growing.
Where are wildfires a risk today?
Just about everywhere there is land to burn. In January, the U.S. state of Colorado lost more than 1,000 homes and saw half a billion dollars in damages as unprecedented wildfires roared through urban communities north of Denver.
Australia, the U.S. West Coast, Canada and parts of southern Europe, among other places, have long been known for their seasonal wildfires. But fire risk is now surging as well in places from Syria to Siberia and India, scientists say.
That is a problem both because governments facing blazes may have less experience managing them, and because fires release the carbon stored in trees into the atmosphere, fueling climate change and reducing the future area of carbon-absorbing forests.
Fires can also cause air pollution and associated health problems, affect rainfall as moisture-producing trees disappear, burn crops and destroy nature, as well as create mental health problems and potential job losses for people living near them.
Growing efforts by companies and governments to offset their climate-changing emissions by paying to protect and expand forests could also be at risk if forested lands are ravaged by fire.
How bad might things get in the future?
Scientists say the kind of "catastrophic" fires that once happened about every 100 years will become 1.3 to 1.5 times more frequent by the turn of the century.
That includes fires like an 1851 blaze in Australia's Victoria state that devastated an area the size of England, said Andrew Sullivan, a bushfire expert at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Canberra.
While particularly destructive, Australia's 2019-2020 fire season did not see a similarly catastrophic fire, rather an unusually large number of more normal fires, said Sullivan, one of the authors of the UNEP report.
Catastrophic-scale fires could happen anywhere, he said - from remote stretches of boreal forest in Siberia to more typical fire-risk areas.
Some could be particularly damaging - such as those in tropical rainforests or other ecosystems where seasonal fires are not a natural occurrence, meaning plants and wildlife are not adapted to fire and may struggle to recover.
"It's not normal to have fires in rainforests," said Glynis Humphrey, a plant conservation specialist at the University of Cape Town and a report author.
What can be done to curb worsening fire risk?
Portugal's fire risk started to rise more than two decades ago as migration out of the countryside to the cities left more land unattended, allowing flammable undergrowth to accumulate.
But from 2003 onwards, following deadly wildfires, officials started reviewing the country's land management and worked to revitalize rural economies, bringing people back into them to cut fire risks.
"Portugal is probably the outstanding example in the world at the moment," said Peter Moore, a fire management specialist with the U.N. Food and Agriculture Organization (FAO), referring to preventative policy action.
Southern African countries, such as South Africa and Namibia, are increasingly setting fuel-clearing fires at the end of the rainy season to reduce the ferocity of blazes during hot and dry times of the year.
Other fire-prone regions - from Australia to the western United States - are trying to adopt aspects of indigenous peoples' fire management techniques.
Such efforts to move away from suppressing fires to regularly using controlled ones are a key to reducing risks of catastrophic fires, the report said.
"There's been a lot of focus on fire suppression and fire prevention for decades. I think we're at a turning point," Humphrey said.
But most governments today still spend far more money fighting fires than figuring out ways to better prepare for and manage them - a losing game as climate change drives bigger, more frequent and more costly fires, the scientists said.
"Too often our response is tardy, costly and after the fact, with many countries suffering from a chronic lack of investment in planning and prevention," the report warned.
(Reporting by Laurie Goering in London @lauriegoering; Editing by Helen Popper: (Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters. Visit http://news.trust.org/climate)