Recent data and model simulations have indicated that anthropogenic climate change can stimulate fire activity, but paleo records (indicators of past climate) also provide us with a view into the past. By using these records, an international team of scientists has discovered that abrupt climate change during a phase of forest expansion can trigger more wildfires. Their findings were recently published online in Proceedings of the National Academy of Sciences (PNAS).
The scientists from the Center for Bio-Archeology and Ecology (i.e. CNRS/Universite Montepellier 2/Ecole Pratique des Hautes Etudes de Paris) assessed the variation in wildfires in response to the abrupt climate change that occurred almost 13 000 to 11 000 years ago.
The period from 15 000 to 10 000 years ago was examined and scientists note that that particular period was characterised by a major change in the environment. They have even said that the change can be described as being similar to the change we are facing today.
To get an idea of what happened then, the scientists reconstructed the history of wildfires from that period. The data they used were 35 sedimentary charcoal and pollen records, and their finding was very interesting. The scientists explained that by studying fossil pollen, they found that biomass burning gradually increased until the start of the Younger Dryas (i.e. the Big Freeze).
While records regarding variation in fire activity between 12 900 and 11 700 years exist, no systematic trend was evidenced at that time. Data shows, however, that the number of wildfires grew after the Big Freeze ended around 11 700, when the world entered the Holocene period, which according to experts, is the period in which we are currently still living.
It should be noted that rapid climate change occurred at intervals of 13 900, 13 200 and 11 700 years, brought on by the expansive fire activity.
Clear links between the large climate changes and fire activity were established, the scientists remarked. According to the authors of the paper, the timing of the changes was ‘not coincident with changes in human population density or the timing of the extinction of the megafauna’, or even the theory about a meteorite bombardment.
These factors may have played a role in the fire-regime changes at various sites or specific times, they explained, adding that the charcoal data show what a significant role the climate plays in determining the major levels of fire activity. This is especially evident in rapid fire change, they added.
The scientists also remarked that the findings offer key information about the possible trends in wildfires in the future.
This latest study followed another study published in Nature Geoscience last October, indicating that the climate played a significant role in the fire regime over centuries before the Industrial Revolution, the team said.
In a nutshell, the findings of the current study suggest that climate-driven fires may increase due to continued global warming and forest expansion. The result of which are new environmental and societal risks, they cautioned.