Climate changes increase the risk of extreme fire by 25% – 08/30/2023 – Environment

Climate change exponentially increases the risk of fast-spreading wildfires. This is what a study published this Wednesday (30) shows, with new clues for prevention after the recent catastrophes that occurred in Canada, Greece and Hawaii.

Human-caused warming has increased the frequency of extreme wildfires by an average of 25% compared to pre-industrial times, concludes this study published in the journal Nature by California’s Breakthrough Institute.

By examining a series of fires from 2003 to 2020, the scientists analyzed the effect of higher average temperatures and drier conditions on very fast-spreading fires, meaning those that burn more than 4,000 hectares a day.

The effect of climate change varies: under conditions of partial drought, warming was sufficient to exceed key air or vegetation moisture thresholds that make extreme fires much more likely, while the impact of warming is much less pronounced in dry conditions. already very dry.

“This means that we should pay more attention to places and periods that have historically experienced conditions just below these thresholds,” lead author Patrick Brown told AFP.

preventive burnings

The risk could increase by an average of 59% by the end of the century in a low-emissions scenario (+1.8°C warming relative to pre-industrial era climate), and by up to 172% in an uncontrollable high-emissions scenario . The climate has already warmed by 1.2°C.

According to Brown, identifying key drought thresholds can facilitate prevention measures, helping to choose priority sites for clearing or controlled burning of vegetation in order to reduce the dry fuel that fires feed on.

“In most conditions, the impact of reductions in hazardous fuels can fully offset the effect of climate change”, says the expert, who also assesses that “the risk of fire can decrease considerably despite climate change” if these measures are applied in Large scale.

The results can also help to better guide surveillance campaigns and the deployment of fire-fighting assets.

The study was published at the end of a summer in the northern hemisphere marked by fires that killed at least 115 people in Hawaii and broke all records in Canada, where 200,000 people had to leave their homes. In Greece, the biggest forest fire ever recorded in the European Union, advances on a front of ten kilometers.