What relationship do extreme wildfires have with climate change?

The latest extreme wildfires in Portugal (2017), California (2018), Tenerife (2023) and Chile (2024), among others, with thousands of hectares burned, have taken place during long periods of drought and high temperatures. This may lead one to think that these fires have happened because of climate change. But is it true? What relationship do extreme wildfires have with climate change? Below, we explain it to you.

Wildfires evolution

In the Mediterranean area, fire has historically been a shaping element of the landscape, and numerous animal and plant species have adapted to its frequency, intensity and seasonality. However, this fire regime has been changing in recent decades.

At 1960s, the annual number of wildfires grew alarmingly until the 1990s, when the number decreased, but, on the contrary, the new fires that occurred could burn large areas. A new phenomenon appeared: extreme wildfires.

Extreme wildfires are characterized by being wildfires that can escape the control of extinction mechanisms due to their great speed of spread, virulence and ability to generate secondary outbreaks. Capable of burning more than 500 hectares, they create very risky situations for the population, and in addition, the regeneration of the areas affected by these fires is usually much more difficult.

Currently, they only represent 2.6% of the wildfires that occur in the Mediterranean, but they represent 75% of the total area that burns. Furthermore, it is expected that these types of wildfires will become increasingly common.

Relationship with climate change

Naturally, wildfires are directly related to drought, since it causes the vegetation to be dry enough to burn. In a context of climate change, this situation get worst. The increase in temperatures with extreme periods of heat, intense desiccating winds and increasingly prolonged and frequent droughts make the vegetation dry out more easily, and are more susceptible to burning with greater intensity, leading to the appearance of larger wildfires. and extremes.

Furthermore, these climatic anomalies lengthen the fire season – the period of the year in which most wildfires take place – thus losing its seasonality. According to CSIC researcher Cristina Santín, from Mieres Mixed Biodiversity Institute “The number of days with meteorological risk of extreme fires has increased around the world and has doubled in the Mediterranean basin in the last 40 years.”

In this context, it can be stated that climate change increases the probability of larger and more extreme wildfires occurring but not more wildfires in general. It is important to highlight that, although climate change is an influential factor, it is not the only factor that is increasing the intensity and spread of extreme wildfires.

Human influence on extreme wildfires

Climate change contributes to the appearance of extreme wildfires, but contrary to what might be thought, the real key factor that causes this type of fire is rural abandonment, and the consequent lack of land management.

In recent decades, farmers and shepherds have stopped managing a large part of the territory due to lack of opportunities in an uncompetitive primary sector in a globalized market. This has led to the expansion of the forest and the loss of a diverse landscape with crops and pastures, in addition to the reduction of forestry exploitation (extraction of wood, firewood and grazing of the undergrowth).

This new situation has encouraged the appearance of landscapes with dense and continuous vegetation, which under the effects of climate change dries easily, thus increasing the risk of suffering from extreme wildfires.

What can we do?

Managing to mitigate climate change and its effects is a difficult task to achieve in the short term. Therefore, one way to reduce the occurrence of extreme wildfires is to act on rural abandonment and promote landscape management.

In this way, it will be possible to create landscapes that are resistant and adapted to the effects of large-scale fires, thus protecting people and the biodiversity of the territory.

To manage landscapes, it is necessary to control the accumulation of vegetation and its continuity, avoiding the formation of continuous forest masses with a very dense and dry undergrowth.

To manage landscapes, it is necessary to control the accumulation of vegetation and its continuity, avoiding the formation of continuous forest masses with a very dense and dry undergrowth.

This control can be carried out, on the one hand, through prescribed burns and selective felling that will help reduce the excess fuel in the forests.

And on the other, through the reactivation of the local primary sector. Recovering the activities of ranchers, farmers or forestry use in the territory will contribute to maintaining a mosaic landscape, that is, alternating forests with crops, bushes or pastures that will allow fires to be less aggressive as there is less dense and continuous vegetation in the area. landscape.

Find out more

• Article by Rosa María Canals in The Conversation. ¿Porque ahora hay más incendios y son más peligrosos?
• Article by Rosa María Canals in The Conversation. Reactivar el mundo rural, clave para prevenir los grandes incendios forestales.
• Article by Stefan H Doerr and collaborators in The Conversation. El cambio climático ha aumentado el riesgo de incendios, pero aún podemos influir en cómo y dónde se producen.
• Post by Angela Justamante the CREAF blog. Las quemas controladas reducen el riesgo de sufrir grandes incendios forestales.
• Article by J.M. Moreno and collaborators in MITECO. Los incendios forestales en España ante el cambio climático.
• Article by Juli Pausas in The Conversation. Incendios forestales: el cambio climático no es su única explicación.
• Article by Víctor Resco de Dios in The Conversation. La era de los incendios que ya no podemos apagar.
• Article by Javier Retana the CREAF blog. Incendios forestales.
• Article by Marco Turco and Sonia Jerez in The Conversation. El cambio climático hará que aumenten los incendios en el Mediterráneo.