Whether in Australia, Siberia or California, there are more and more devastating major fires. With climate change, the risk of such fires increasing – researchers have calculated how strong the effect already is.
The risk of forest and bush fires is increasing in many regions of the world as a result of climate change. A team of researchers reports in the journal “Reviews of Geophysics” that weather conditions that promote the outbreak and spread of fires are becoming more frequent. According to the analyzes and models, between 1979 and 2019 the period with corresponding weather conditions worldwide had already been extended by an average of 14 days.
‘Ultimately, as the world continues to warm, we will (…) have to fight the increasing risk of fire,’ said Matthew Jones of the Tyndall Center for Climate Change Research in Norwich, UK. “Redoubling efforts to reduce greenhouse gas emissions and limiting warming to below two degrees Celsius is the most effective thing we can do to avoid the worst wildfire risks on a global scale.”
In their review, the scientists evaluated the results of 500 studies and reanalyzed data sets from satellite measurements and from climate models. Among other things, they came to the conclusion that between 1979 and 2019 the number of days on which the weather conditions were extremely favorable to fire increased by ten days on average worldwide.
The increase is most pronounced in western North America, Amazonia and the Mediterranean. Several of the major wildfires of recent years have occurred under weather conditions that climate change has made significantly more likely, the authors write, citing the Australian bushfires of 2019/2020 as an example.
In many regions of the world, with the increased risk of fire, more area was burned, but globally it was less: between 2001 and 2019, the area burned decreased by a quarter or 1.1 million square kilometers. This is due to the fact that other influencing factors regionally overshadowed the effects of climate change, such as the conversion of forests into agricultural areas or the increasing fragmentation of natural regions.
Most of the decline – 590,000 square kilometers – is in the savannahs of Africa. Jones explained that the global trend primarily reflects the decline in bush fires in the savannas. “In other words, the global trend hides a significant increase in forest fires, which of course are often more dangerous to society.”
The main reason for the decline in the savannas is the conversion to agricultural land, which reduces the risk of fires breaking out. In addition, plant productivity decreases with the increasingly drier rainy seasons, which means that less fuel is available.
“Despite the fact that weather conditions favorable to wildfires have already increased and will continue to increase in almost all regions of the world, human factors still play a role or take precedence over climatic factors in many regions,” said Cristina Santin of the British Swansea University.
The influence of climate change on the risk of fires will increase in the future, with each degree of warming increasing the risk, the researchers write.
