Climate Change Intensifies Overlapping Wildfire Seasons in Australia and North America.

A recent study has highlighted a concerning shift in wildfire patterns, showing that climate change is driving more frequent overlaps between the fire seasons in eastern Australia and western North America. These regions, which have long been plagued by devastating wildfires, are now facing heightened risks due to specific weather conditions known as "fire weather." The research, published in Earth's Future, examines how climate change is altering these fire seasons and the potential implications for cross-border firefighting efforts.

Both the east coast of Australia and the west coast of North America have been severely affected by wildfires in recent years. For instance, in January 2025, Los Angeles faced one of its most catastrophic wildfire seasons, which destroyed more than 10,000 buildings and led to 29 fatalities. Similarly, between 2019 and 2020, eastern Australia endured one of its most destructive bushfire seasons, burning over 12 million hectares of land. Firefighting teams from the United States, Canada, and Australia have often collaborated to combat these large-scale disasters, but the increasing overlap of fire seasons is creating significant challenges for international cooperation.

The research team, consisting of scientists from the Helmholtz Center for Environmental Research (UFZ) in Germany and their Australian counterparts, used the Canadian Fire Weather Index (FWI) to analyze the timing and severity of fire weather in these regions. The FWI is a globally recognized tool that takes into account rainfall, temperature, humidity, and wind speed to estimate fire risk. According to their findings, the number of overlapping fire weather days has steadily increased since 1979, with a particularly high likelihood of overlap—around 75%—occurring between July and December.

This change is attributed to the fact that the fire season in eastern Australia is now starting earlier in the spring and extending into the period when the fire season in western North America typically ends. Over the past 40 years, the simultaneous occurrence of fire weather days in these two regions has been increasing by one day each year, with projections suggesting that this trend will continue into the future. Depending on global warming scenarios, the overlap could increase by 4 to 29 days per year by the mid-21st century.

The increased overlap is partly driven by the El Niño Southern Oscillation (ENSO), a climatic phenomenon that affects weather patterns in the Pacific region. While fire weather in eastern Australia is often associated with El Niño conditions, which bring higher sea surface temperatures and drought, fire weather in western North America is more commonly linked to La Niña conditions. Despite these opposing patterns, the research found that during periods of strong overlap, El Niño conditions in the central Pacific were especially pronounced, exacerbating the risks of wildfires.

While El Niño's influence remains significant, the study emphasizes that climate change is the dominant factor in the intensifying wildfire risk. Rising global temperatures and increased droughts are making conditions more favorable for fires, particularly in regions already prone to wildfires. This evolving climate pattern is further complicating efforts to manage fires in both regions.

The increasing overlap of fire seasons is creating challenges for firefighting cooperation. In the past, fire seasons in eastern Australia and western North America occurred at different times of the year, allowing firefighters to assist one another across borders. However, as these seasons begin to coincide, the window for international support is shrinking, making it more difficult to mobilize resources quickly.

As a result, experts warn that international agreements on firefighting cooperation need to be reassessed. Both the United States and Australia will need to strengthen their domestic firefighting capacities to reduce reliance on international aid, ensuring that they are better prepared to respond to the growing wildfire threat in the coming decades.

Source:https://phys.org/news/2025-04-climate-overlapping-wildfire-seasons-australia.html

This is non-financial/medical advice and made using AI so could be wrong.