The term ‘megafire’ sounds a bit serious ... and so it is. Even more serious is the idea – raised in a report compiled for a UN meeting recently – that megafires are becoming more frequent. Still more alarming is the notion that these megafires are somehow quantitatively different from their smaller and more common cousins: “Megafires exceed all efforts at control until firefighters get a favourable change in weather or a break in fuels. Even in countries with modern tools and techniques to combat severe wildfires, firefighters are generally forced onto the defensive; taking action where they can on the fire’s terms.”

The grand-daddy of the fires we’re talking about here is the sequence in Kalimantan on Borneo in 1997/8, where forests smouldered for many months, sparked by extremely dry El Nino conditions.

The episode smoked out much of East Asia, with people in countries such as Malaysia, Thailand and The Philippines suffering respiratory diseases, and economic damage put in the billions of dollars.

Since then, Brazil in 1998, the US in 2003, Greece in 2007, Botswana in 2008, Australia in 2009, and both Israel and Russia in 2010 have all seen conflagrations that the report’s authors believe merit the description ‘megafire’.

The paper’s been written by a team of ten experts from across the world, at the behest of the UN Food and Agriculture Organisation (FAO), and has been released at the Wildfire 2011 conference in South Africa.

The list of eight fires listed above isn’t exhaustive, and Kalimantan wasn’t the first megafire. But being the most recent, this group has been better studied than most, especially given the modern availability of satellite monitoring; so it is with this group that the FAO panel concerns itself. Is there a pattern across these fires? And if so, what factors, environmental and other, does it relate to?

The answer to the first question appears to be a cautious “yes – probably.”
Virtually all had a human cause – mostly intentional – ranging from lighting camp fires in Europe to clearing forests for farmland in Indonesia. Extreme weather, especially drought, was another common factor. And in virtually all, the forest had been “altered” as a result of intensive logging, land clearance, and development for human settlement.
And what of the climate?

The El Nino conditions of 1997/8 were extraordinary for the modern era. But given that climate models predict declining rainfall in some areas that are already rather dry (parts of Australia perhaps being the exemplar here), what does that imply for the future?

Here, the FAO does not draw firm conclusions – and given the uncertainties in climate modelling and the fact that there is a limited dataset of past fires on which to draw, their caution is easily understood. Nevertheless, a cautionary note is raised:

“With the onset of more pervasive, world-wide drought, there is no longer the assurance that some places, only because they have not had severe wildfires in the past, will be safe from conflagrations in the future.”

But there is also a fillip: “Mega-fires are not occurring where land management practices are consistent with the fire ecologies and disturbance dynamics that define the ecosystem. Mega-fire risk is likewise much reduced in those areas where wildfire protection programmes are more balanced between prevention, mitigation, and suppression elements.”

The one thing governments and their people must not do, the report cautions, is to treat megafires as something that can be combated with greater numbers of firefighters or more sophisticated means of aerial assault.

Treat them as living entities

Instead, they need to be understood as a natural phenomenon, but as living entities, subject to the whims of weather, and capable of being coaxed into relative quiescence. And addressing them is best done with forest management – although the report notes that here there is a question of skills declining around the world. In terms of what climate change means here, you can draw something of a parallel with coral reefs.

A healthy reef may be able to bat away the impact of exploitative fishing or excessive pollution from land. But coral impacted by rising temperatures and progressively less alkaline oceans may not be able to. So too, the FAO suggest, with fire.

Controls that worked in a cooler, wetter environment may not work at all as the world warms, the addition of climate change to other factors driving fires may be what’s already causing the rise in incidence that the report suggests.

A final note on the climate front. The 1997 Kalimantan fires released about as much carbon dioxide as Europe’s industry – plus the fact that those trees were not there any more to absorb CO2.

So in principle, megafires could be another positive feedback loop for CO2-driven warming, especially if they are increasing as the FAO suggests: “Because CO2 emissions contribute to global warming and mega-fires are the result of drought, mega-fires (and carbon releases) may represent a dangerous feed-back loop that becomes self-perpetuating in the absence of stronger wildfire emissions monitoring and control. Little is known of this possible iterative relationship and its long-term ramifications.”