For centuries if not millenia, people have used controlled fire as a vital tool to curb wildfire risks by preemptively burning dry timber and other fire fodder that could fuel out-of-control blazes.

Around the world, such proactive fire-setting is seen as one of the cheapest and most effective ways to limit catastrophic fire risk, which is swiftly rising as climate change brings hotter temperatures and harsher droughts.

But in the United States, spiking insurance costs and wary providers now present an existential threat to such efforts, according to officials and groups trying to promote “good fire.”

“Without sounding alarmist, it frankly couldn’t be more dire - at least on the national level,” Lasky said.

Analysts say the approaching end of affordable “prescribed burn” insurance coverage is just one example of how, as climate change drives growing losses from disasters such as wildfires, floods, and storms, access to insurance protection from them also is weakening.

That is leaving many more families, organisations and governments at growing financial risk, they say.

Major problems accessing affordable controlled fire insurance have been percolating for at least several years, if not longer, according to Daniel Godwin, a fire management planning specialist with the US Forest Service.

Anxious insurers increasingly fear that preventive fires could escape - even if that happens very rarely. “Even if it isn’t actually that risky, the perception matters,” Godwin said.

The Forest Service estimates that of the 4,500 controlled burns it conducts on average every year, more than 99 percent go according to plan, translating to about six annual escapes.

Even that tiny share, though, has the potential to be immensely destructive, giving insurers pause.

One of the worst came last April, when escaped US Forest Service burns ignited the huge Calf Canyon/Hermits Peak Fire in the state of New Mexico, incinerating hundreds of homes in the state’s largest-recorded wildfire.

Government agencies like the Forest Service and state forestry departments frequently self-insure for damages associated with escaped burns - covering the costs themselves - or have a qualified immunity or gross negligence liability insurance policy.

But most prescribed fire in the United States happens on private land, Godwin said, and the nonprofits and trusts crucial to carrying it out are being squeezed out of the market.

Read the full article about insurance for wildfires by Thomson Reuters Foundation at Eco-Business.