California is still burning. What's the cause?
I hope you are safe and well. Writing this post is déjà vu. After living through and writing about Australia’s wildfires in January, it has been California’s turn. Over the past month, hundreds of wildfires have ripped through the West Coast of the USA and more than 3 million acres have been burned in California alone, making it the largest wildfire event in the states modern history.
Like what happened in Australia, everyone seems to have their own perspective on the cause. President Donald Trump for example recently told supporters the California fires were because of ‘forest management’. Meanwhile, Democratic Presidential candidate Joe Biden linked it to climate change. So what’s the truth? We asked 11 global fire and forest experts to shed some light on this debate.
Climate change is likely increasing wildfire risk in California, but it’s just one factor
The evidence that climate warming has increased the risk of wildfires is over-whelming (you can read our analysis of the Australian bushfires or see this recent analysis by researchers at ScienceBrief). But what about California specifically?
Not even including this latest mega-fire, the amount of land burnt by wildfires in California has gone up 5-fold since 1970.
California is getting hit with more and larger fires and those researchers found that this is “very likely” driven by drying of fuel loads on the ground, “promoted by human‐induced warming”. This analysis doesn’t even include the latest wildfires which are 3-times the scale of the 2017 California wildfires.
A new study from NASA shows exactly how climate change is already impacting temperatures, drought and therefore risk of wildfires in California. Like for Australia, the evidence shows California is going through hotter, more intense and more frequent heat-waves over the past few decades. Combine this with dry conditions, like I wrote about for the Australian bushfires, climate change is likely having an important role to play in making these types of destructive wildfires worse.
But climate change is NOT the only factor. Forest management is also important. It’s a vague term around authorities attempting to manage the fuel load on the ground. But much debate revolves around the concept of hazard reduction burning, sometimes called prescribed fire or intentional burning. Many people believe this practice is a proactive preventative measure against wildfires even in a hotter world. Is that true? We asked 11 global experts on fire management. Here’s what we found.
What is Hazard reduction burning? It’s not ‘back-burning’
Fires need an ignition (often it’s lightning) but also vegetation fuel for it to spread. Wildfires are more containable when there’s less-flammable fuel material to exacerbate them.
‘Hazard reduction burning’ simply reduces the amount of vegetation and biomass available to burn
says Dr Crystal Kolden an expert in fire science from the University of Idaho in Fire.
Hazard reduction burning occurs outside the fire season says Professor Philip Gibbons, forestry expert from the Australian National University. Many forests are adapted to fire and can quickly regrow so hazard reduction burning must be performed in up to six-year intervals if it's to succeed he says. This practice is commonly confused for back-burning, a method used to offset fires already in process.
Wildfires cannot be prevented but hazard reduction still important
Dr Joshua Johnston, an expert from the Canadian Fire Service says hazard reduction “reduces the available fuel and intensity for future fires” but doesn’t prevent fires he writes.
The mitigating properties of hazard reduction burning depends on varying factors such as time-lag following the treatment. Therefore, according to Johnston, even when using this method, it's not guaranteed to be an effective suppressor either.
Even more intriguing is that hazard reduction burning increases bushfire frequency in certain areas, according to Dr Kolden. The process promotes grass-growth in specific ecosystems, which generates vastly more fires but with less disastrous results. In fact, igniting more fires is part of maintaining the African Savannah grasslands.
Dr Johnston also points out that many people make the mistake of correlating hazard reduction burning and decreased fire activity. This assumption is due to the years with increased reduction-burning occurring alongside fewer wildfires requiring suppression.
The Canadian Fire Service Forestry expert claims that the above conclusion is 100% incorrect and that the relationship is inverse. With fewer wildfires to suppress, more firefighters and money are available. This results in more focused management practices and hazard reduction burning. Conversely, there are fewer surplus resources and manpower dedicated to hazard reduction burning when there's more suppression during the year.
Based on the expert consensus, it’s clear that nothing can prevent future wildfires like the ones in California or Australia. Hazard reduction should still be used but even the best managed forest will still have enormous fuel loads ready to fire up under hotter drier conditions under climate change.
The winners are Alcohol, Stem Cells and Mindfulness
There was a 3-way tie in last months member poll between alcohol, stem cells and mindfulness. They are all great topics to cover - so we will add them to the list for our member reviews. Next month we will be doing a mini-review on ‘Multi-vitamins’ and ‘Anti-ageing’.
Stay safe and may the facts be with you!
Ben McNeil, Founder of Metafact
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