A warming planet and changes to land use patterns mean more wildfires will scorch large parts of the globe in coming decades, causing spikes in unhealthy smoke pollution and other problems that governments are ill prepared to confront, according to a UN report being released Wednesday.
The western U.S., northern Siberia, central India, and eastern Australia already are seeing more blazes, and the likelihood of catastrophic wildfires globally could increase more than 50 per cent by the turn of the century, according to the report from the UN Environment Program.
Areas once considered safe from major fires won't be immune, including the Arctic, which the report said was "very likely to experience a significant increase in burning."
Tropical forests in Indonesia and the southern Amazon of South America also are likely to see increased wildfires, the report concluded.
"Uncontrollable and devastating wildfires are becoming an expected part of the seasonal calendars in many parts of the world," said Andrew Sullivan, with the Commonwealth Scientific and Industrial Research Organisation in Australia, one of the report's authors.
How warmer nights sustain fires
At the same time, the slow disappearance of cool, damp nights that once helped to temper fires also means they are getting harder to extinguish, according to a second study published last week in the journal Nature.
With nighttime temperatures rising faster than daytime ones over the last four decades, researchers found a 36 per cent increase in the number of after-dark hours that were warm and dry enough to sustain fire.
"This is a mechanism for fires to get much bigger and more extreme," said Jennifer Balch, lead author of the Nature study and director of the University of Colorado Boulder's Earth Lab.
"Exhausted firefighters don't get relief," she said, which means they can't regroup and revise strategies to tackle a blaze.
Growing costs and damage
The consequences of extreme fires are wide-ranging, from loss and damage to costly firefighting response. In the United States alone, the UNEP report said the economic burden of wildfire totals as much as $347 billion US annually.
With California's forests ablaze, the state government spent an estimated $3.1 billion US on fire suppression in the 2020-21 fiscal year.
The fires raging since December in Argentina's Corrientes province have taken an enormous toll, killing Ibera National Park wildlife, charring pasturelands and livestock, and decimating crops, including yerba mate, fruit and rice. Losses already have exceeded 25 billion Argentine pesos ($296 million Cdn), the Argentine Rural Society said.
UN researchers said many nations continue to spend too much time and money fighting fires and not enough trying to prevent them. Land use changes can make the fires worse, such as logging that leaves behind debris that can easily burn and forests that are intentionally ignited to clear land for farming, the report said.
In the United States, officials recently unveiled a $50 billion US effort to reduce fire risks over the next decade by more aggressively thinning forests around "hot spots" where nature and neighbourhood collide. However, the administration of President Joe Biden has so far identified only a fraction of the funding called for in the plan.
"In many regions of the world, most resources go toward response — they focus on the short term," said Paulo Fernandes, a contributing author of the UNEP report and fire scientist at Universidade of Tras-os-Montes and Alto Douro in Portugal.
The UNEP report calls on governments to rethink wildfire spending, recommending they put 45 per cent of their budget toward prevention and preparedness, 34 per cent toward firefighting response and 20 per cent for recovery.
The UN researchers also called for more awareness of the dangers from smoke inhalation, which can affect tens of millions of people annuall y as plumes from major wildfires drift thousands of miles across international borders.
