All over the world, entire forest areas are going up in flames more and more frequently. This has devastating consequences for people and the environment. An Australian research team is investigating the role played by climate change - and draws a bleak future.
660,000 hectares, the equivalent of almost 100,000 football fields: That's how much forest area went up in flames this year - in Europe alone. Due to the advancing climate change, the risk of forest fires is increasing worldwide. Without effective climate action, forests on all continents will be highly flammable for at least 30 extra days a year by the end of the century, Australian scientists are now warning.
For their study, which was published in the journal "Nature Communications", Hamish Clarke's research team evaluated satellite data from the last 20 years. They investigated the connection between forest fires and the vapor pressure deficit (Vapor Pressure Deficit, VPD). VPD describes the ability of the atmosphere to remove moisture from living and dead plants. The researchers describe this as "thirsty air".
The result: Forest fires become much more likely in many regions above a certain vapor pressure deficit threshold. If humanity continues to release greenhouse gas emissions unabated, the earth is expected to warm by about 3.7 degrees Celsius by the end of the century. In this high emissions scenario, the study finds that every continent has forests that will exceed critical flammability thresholds on at least 30 additional days per year.
Under a lower emissions scenario that limits global warming to around 1.8 degrees, each continent will still see at least 15 additional days per year exceeding the threshold. Parts of tropical South America, including the Amazon, will see the largest increases by the end of the century in both scenarios: at least 90 extra days in a low emissions scenario and at least 150 extra days in a high emissions scenario.
According to the research team, the cause lies in the saturation capacity of the atmosphere as temperatures rise. Warmer air can hold more water, which in turn is withdrawn from living and dead plants. Once a certain threshold is reached, forests dry out and become more susceptible to fires. "It is alarming that climate change is increasing the number of days the planet exceeds these critical thresholds," the scientists write.
According to the study, the increase in forest fires has devastating consequences for people and the environment. This affects carbon storage. Studies in recent years have shown that the role of the Amazon rainforest as a so-called terrestrial carbon sink (more CO2 is absorbed than emitted) is already under serious threat. Deforestation, fires and rapid local warming have reduced and in some cases even eliminated its ability to sequester carbon dioxide.
The researchers also warn of increasing damage to health from the smoke from forest fires. It is estimated that more than 330,000 people die each year worldwide as a result of smoke inhalation. This number could increase significantly by the turn of the century, particularly in the most densely populated areas of South Asia and East Africa.
