Climate Change and Fire


Climate change and bushfire management in Western Australia


A position paper prepared by The Bushfire Front Inc, August 2017

In the aftermath of almost every serious bushfire in recent years, there have been claims that the severity of the fire was the result of “global warming” or “climate change”. Even Western Australia’s Fire Commissioner claimed that the disastrous Yarloop Fire was a direct consequence of climate change. The trouble with blaming bushfires on climate change is the inference that the problem is hopeless, because nothing can be done in the short term to change the climate. Worst of all, it ignores the role of high fuel loads in rendering wildfires unstoppable, a problem that can be readily fixed.

There are many different opinions on the issue of global warming and climate change. Debate is difficult because emotions, politics and ideology enter into it. The BFF view is that we must put aside the question “is catastrophic climate change upon us, is it caused by human emissions of CO2 and is it the cause of unstoppable bushfires?”and focus instead on the fires and what can be done about them.

The Bushfire Front position is:

1. The south-west of WA has experienced below-average rainfall dating back to the 1970s. There have been dry periods in WA before, e.g., in the late 1800s. The current below-average rainfall period could be a permanent change, or could be a long-term cyclical event. Nobody knows.

2. The reason for below-average rainfall is that the low pressure systems that bring the cold fronts and winter rains are now passing to the south of the State. The reasons for this are not known or are disputed. However, the cause is irrelevant, because there is nothing we can do about it. We are concerned with the consequence, how this effects bushfire behaviour and with the adoption of remedial actions that are practical and economical.

3. The critical consequence is that below-average rainfall leads to drier fuels especially earlier in the fire season. Drier fuels lead, in turn, to more intense fire behaviour, especially during the period in which fuel reduction burning has traditionally occurred. Thus, drier fuels can result in more intense fires, and reduce the number of suitable days for fuel reduction burning. An indirect consequence is the need to employ personnel on fire-fighting instead of fuel reduction burning during the spring period.

4. There is a significant related factor: over the drier period, there has also been a decline in fuel reduction burning, especially in south-west forests. This produced a “double whammy”: fuels are both heavier and drier.

5. Compared to slope, wind strength, fuel quantity and dryness, temperature is an insignificant driver of fire behaviour. Experienced firefighters do not fear a 40-degree day per se. This is because even on a hot day, a fire in one or two-year old fuel can be controlled; on the same day a fire in 20-year old fuels with high winds would usually be unstoppable.

6. There is nothing that anyone in WA can do right now to return rainfall to the levels that prevailed in the 1950s and 1960s. Even if the current drought is caused by CO2 emissions, this is a world-wide phenomenon, and even if effective emission-reduction programs are introduced worldwide, they will not take effect for many years. In any case the relationship between atmospheric CO2 concentrations and rainfall in the south-west of WA is unknown.

7. Bushfire authorities can take two alternative approaches. Either:

* employ more firefighters, water bombers, and super-technology to increase the State’s bushfire suppression capability (the emergency response approach); or

* invest in fuel reduction to reduce fire intensity and make it easier, safer and cheaper for the existing fire suppression capability to control wildfires (the bushfire mitigation approach).

8. The BFF supports a fire management system built upon mitigation and resilience. Relying on increased suppression forces and technology is not the answer. Fires in heavy, dry fuels in eucalypt forest on a windy day cannot be controlled, regardless of the fire-fighting resources and technology available.

9. In other words: irrespective of the cause of the current drought, the only way to counter its consequences is through bushfire mitigation, including fuel reduction. For example if jarrah forest fuels are managed on a 5-7 year cycle, the impact of projected warming and drought can be managed.

10. Drier winters have one advantage: they provide an opportunity to achieve effective winter burning, particularly in open and drier jarrah and wandoo forests/ woodlands in the north and eastern forest regions and in some areas of heathland in the south-west.

11. Carbon dioxide emitted in smoke from a mild-intensity burn is rapidly recaptured through photosynthesis by regenerating understorey plants and by increased tree growth so that the situation is carbon-neutral within 2-4 years of a burn. After this there is positive accumulation of CO2 in plants.

12. However, release of CO2 in a large, high-intensity wildfire is more significant, firstly because so much more fuel is burnt and CO2 released, and secondly because the recovery period is so much longer. Fuel reduction burning that minimises the occurrence of large high-intensity wildfires is therefore beneficial in terms of minimising release of CO2 to the atmosphere.

13. In summary then, the BFF position on bushfire management and global warming/climate change is as follows:

* southwest WA is experiencing a period of prolonged below-average rainfall;

* the cause is not known to be something that can be fixed in the short term;

* the consequence of the drought is drier fuels, especially in spring, and potentially more intense fire behaviour;

* this impact can be minimised by systematic fuel reduction, including winter burning;

* simply increasing suppression capability without reducing fuels will not result in an improved bushfire outcome … indeed the reverse will be the case, as we have experienced over the last decade in WA ; and

* fuel reduction burning has less impact on atmospheric CO2 than does large, high-intensity wildfires.