Scenes of residents and tourists cowering on beaches to escape ferocious wildfires engulfing all before them are, undeniably, of great concern to us all. And seeing such scenes on the eve of the publication of an IPCC assessment report that focuses executive attention upon increased frequency and severity of extreme weather events only adds to their poignancy. We know already that scientists are obsessed with the necessary role that climate change plays in events such as the recent Greek forest fires. The fact that a warming planet must, perforce, lead to extended burning seasons is difficult to deny. So surely there is nothing left to be said.
Except, when it comes to forest fires, there’s always plenty more to be said. You might not suspect so when reading the typically simplistic reports emerging from the mainstream media, but trends in such fires are always a result of a complex interplay between climatic change, availability of combustible material and human activity. The Greek fires are no exception, so let us look under the hood a little to see what the full picture looks like.
I have taken as my main source of information an analysis of Greek forest fires provided by the Climatechangepost website. This is a site dedicated to the promotion of the various adaptation measures deemed necessary to deal with climate change. The site does not entertain sceptical views regarding anthropogenic climate change, and so you may be assured that no part of the analysis was written specifically for the benefit of those with a sceptical mind-set. Nevertheless, I choose here to highlight those elements of the analysis that place the Greek fires in their broader context, since this may be of interest to the curious. If you wish instead to make up your own mind, then by all means consult the Climatechangepost analysis directly. If you are happy to accept my summary of highlights, then please read on:
1) The number of fires and areas burnt is correlated with rainfall and not temperature
Looking back at the historical trend between 1900 and 2010, the analysis states:
“During the period 1961–1997 there was a statistically significant increasing trend and a positive correlation between the number of fires and area burned and the annual drought episodes in Greece (1,2). Summer drought episodes did not show any particular trend for the same period. The average number of fires and area burned were significantly higher in Greece during the sub-period 1978–1997, when Greece entered a prolonged period of drought, compared to the previous sub-period 1961–1977 (1). From a statistical analysis of fire occurrence in Greece during 1900–2010 it was concluded that total area burned at the national scale is controlled by precipitation totals rather than air temperature (3).”
The distinction between increased temperature and drought may seem academic, but the two do not necessarily correlate and this has implications for Detection & Attribution studies that attempt to attribute local drought events to global warming.
2) The recent wildfires are by no means unprecedented and have been less destructive than the 2007 wildfires
The favourite quote presented by the media regarding the 2021 fires is that “we have never seen anything like it”. For example, there is this from Nikos Hardalias, Greece’s civil protection chief:
“Over the past few days, we have been facing a situation without precedent in our country, in the intensity and wide distribution of the wildfires, and the new outbreaks all over [Greece]”
People have short memories. Admittedly, it is early days but the forest fires of 1998 and 2007 were actually much more destructive and resulted in a much greater loss of life than the 2021 fires. Regarding the 2007 fires:
“The estimation for the cost of the damages for the 500,000 people affected was close to 3 billion euros according to European sources (4), while other moderate estimations have found it to be close to 2.2 billion US dollars (5). During the 2007 summer period, 68 people were killed, while another 2,094 people were injured (6). More than 100 villages and settlements were damaged; the burned forest and agricultural land constitutes about 2 % (190,836 ha) of the total area of Greece (7,8).”
It is also worth pointing out that the main reason for this particularly extensive set of forest fires was an over-accumulation of combustible material:
“The large burnt areas of 2007 fires season in Peloponnese Peninsula appear to be more sensitive to fuel availability and vegetation density than to vegetation dryness (9).”
It remains to be seen what role this has played in the 2021 fires.
3) The recent trend regarding Mediterranean wildfires is not that of an uninterrupted rise
Whilst it is true that the period 1900-2010 has seen a gradual increase in the numbers and extent of forest fires, the trend has been by no means straightforward as patterns of drought and fuel availability have taken their affect. This is not just true for Greece but for the Mediterranean in general. For example:
“A study on the Mediterranean region on fire trends in Portugal, Spain, southern France, Italy, and Greece in the period 1985-2011 revealed a general decreasing trend of the total annual burned area in all countries, with the exception of Portugal (10).”
4) Rural depopulation of northern mountain areas has been a key factor in recent wildfires
I have already mentioned the relevance of surface burning material to the 1998 and 2007 fires. This is a recurrent factor, however, and it is largely determined by human behaviour. With regard to the 1998 and 2007 fires, the analysis states:
“These fires most likely have had more surface burning fuel to propagate compared with those in previous decades because of rural depopulation in northern mountains of the Mediterranean, thus resulting in (a) reduced harvesting of biomass and (b) longer periods of fire exclusion (during which burning fuel accumulated) because of lower human activity (12).”
The analysis warns of worse to come if the current socioeconomic trend continues:
“Mediterranean mountainous areas may face a very large threat from wildfires in the twenty-first century, if socioeconomic changes leading to land abandonment and thus burning fuel accumulation are combined with the drought intensification projected for the region under global warming (4).”
5) The fire risk season can be expected to lengthen in most (but not all) Mediterranean countries, but the removal of accumulated dead biomass will mitigate the risk significantly
The future trend of forest fires in the Mediterranean is expected to be of an increase, resulting from a lengthening burn season:
“Forest fire danger, length of the fire season, and fire frequency and severity are very likely to increase in the Mediterranean (13), and will lead to increased dominance of shrubs over trees (14).”
But not for everyone:
The islands of Crete, Sardinia, Sicily (southernmost Italy too), Peloponnese, and Cyprus see no increase or decrease. Cyprus may even see a small decrease every month.
However, trying to reduce the lengthening of the fire season by cutting carbon dioxide emissions is not a cost-effective risk reduction strategy. The key to controlling the risk lies in adequate risk assessment tools, effective forestry management and keeping on top of the accumulation of surface burn material:
“Developing fire risk assessment tools that enable long-term fire danger prognosis (15) and battling the accumulation of burning fuel should be a top priority to reduce fire spread, especially if rural depopulation further continues in northern mountains of the Mediterranean (14).”
“Thinning and pruning may significantly reduce the risk of developing active and passive crown fires, giving the opportunity for successful countering of a possible fire from ground and air forces, since the fireline intensity of the front is significantly reduced, as a result of the fire’s confinement to the surface.”
Unfortunately, a major tool in the forest fire fighter’s armory is not available to the Greek authorities:
“Controlled or prescribed burning as a means to reduce surface fuel is not allowed under Greek legislation (7).”
Perhaps this last point should have been made more of by the media.
I have not written the above in order to dismiss the importance of the 2021 Greek wildfires, nor to deny that climate change will play a role in the outbreak of future forest fires. However, as is always the case, the reality on the ground is far more complicated than one might think given the shrill remonstrations made by those who demand an urgent transition to net zero carbon emissions. Risk may be reduced in a number of ways and the determination of the most cost-effective risk management strategy requires a full understanding of the factors leading to previous wildfire events and any underlying trends. Putting it all down to rising temperatures that can only be mitigated by reductions in carbon dioxide emission is both simplistic and misleading. I’m guessing, however, that will not be the message delivered by the IPCC’s AR6 executive summary.
1. Dimitrakopoulos et al. (2011)
2. Camia and Amatulli (2009); Hoinka et al. (2009); Costa et al. (2011); Koutsias et al. (2012), all in: IPCC (2014)
3. Xystrakis et al. (2014)
4. Davidson (2007), in: Mitsakis et al. (2014)
5. Statheropoulos (2008), in: Mitsakis et al. (2014)
6. USAID (2007), in: Mitsakis et al. (2014)
7. Xanthopoulos et al. (2006), in: Zagas et al. (2013)
8. Koutsias et al. (2012), in: Xystrakis et al. (2014)
9. Gouveia et al. (2016)
10. Turco et al. (2016), in: Silva et al. (2019)
11. Christopoulou et al. (2013), in: Sarris et al. (2014)
12. Sarris et al. (2014)
13. Santos et al. (2002); Pausas (2004); Moreno (2005); Pereira et al. (2005); Moriondo et al. (2006), all in: Alcamo et al. (2007)
14. Mouillot et al. (2002), in: Alcamo et al. (2007)
15. Sarris and Koutsias (2014), in: Sarris et al. (2014)