Uncovering the Impact of Wildfire Soot: How California Fires are Changing the Climate

The study conducted by UC Riverside doctoral candidate James Gomez sheds light on the impact of large wildfires in California on the climate. The research, published in the journal Atmospheric Chemistry and Physics, reveals that soot emitted from these wildfires plays a significant role in trapping sunlight, leading to warmer and drier conditions than usual.

Gomez analyzed data from the past 20 years, focusing on peak fire days and emissions during fire seasons. He specifically looked at days with lower temperatures and higher humidity to isolate the effects of wildfires on the weather. The study found that large fires indeed make the days hotter and drier, creating favorable conditions for more fires to occur.

The most intense fires were observed in Northern California, where dense vegetation fuels the flames. On average, temperatures were approximately 1 degree Celsius warmer per day during these fires. The study attributes this phenomenon to two main factors: soot trapping heat and reducing humidity, making it harder for clouds to form.

While sulfate aerosols, reflective particles from fossil fuel burning, have a cooling effect on the environment, their reduction due to air quality improvements can exacerbate climate change and increase wildfires. On the other hand, black carbon, an absorbing aerosol emitted from wildfires, contributes to higher temperatures and hinders cloud formation, leading to less precipitation.

Gomez emphasizes the importance of reducing greenhouse gas emissions like carbon dioxide and methane to prevent additional wildfires. He suggests implementing better land management practices, such as more frequent prescribed burns, to reduce the buildup of vegetation and ultimately decrease the occurrence of large wildfires.

Overall, the study highlights the complex relationship between wildfires, aerosols, and climate change, underscoring the need for proactive measures to mitigate the impact of wildfires on the environment and public safety.