Impact of Humans on Forest Fires: Historical Context and Natural Fires in the Past

Forest fires are a natural and important part of the ecosystem, contributing to the survival and growth of new plant species. However, the way humans have managed wildfires has significantly changed their behavior and intensity. This article explores the historical context of wildfires, how human intervention has affected them, and the conditions that led to forest fires in the past.

Human Intervention: Extinguishing Every Wildfire

The United States has a long-standing policy of extinguishing every wildfire as soon as it starts, regardless of the cause. This proactive approach, while well-intentioned, has inadvertently led to a build-up of fuel, making modern wildfires burn hotter and longer than they would have if allowed to follow their natural course. According to the wildlife management expert, the current policy of preventing all natural fires has led to giant wildfires that can burn for weeks or months and are nearly impossible to stop.

Natural Forest Fires in Historical Context

Historically, natural wildfires were smaller and less frequent in the absence of human intervention. As noted by climate researchers, during warmer periods with abundant rainfall, such as the Palaeocene-Eocene Thermal Maximum (PETM) approximately 50 million years ago, forest fires were rare. The cooling of the Earth due to a decline in the obliquity of its spin axis has caused changes in global climate, leading to the accumulation of snow and ice on Antarctica 45.5 million years ago and in the Arctic 2.58 million years ago.

The Evolution of Early Humans and the Impact on Forest Fires

The evolving conditions forced early humans to adapt to more open terrain. Reduced rainfall and the contraction of rainforests into areas with more grassland forced early ancestors out of their traditional habitats and into environments less protected from the elements. This adaptation led to changes in their physical capabilities, including developing the ability to walk upright and enhancing their cognitive skills. The use of fire for warmth and as a hunting tool became a critical survival mechanism as early humans encountered more severe weather conditions and faced the threat of more frequent wildfires.

Glaciation's Effect on Wildfires

The increasing glaciation of the Arctic has led to a more pronounced impact on the Earth's orbital elements, which in turn has affected the regions bordering the North Atlantic. The Gulf Stream's deflection southward due to the presence of the British Isles has denied warm equatorial water to the Arctic, resulting in significant declines in sea levels. This drying up of land, combined with the loss of vegetation, has made the land and shallow marine species more vulnerable to wildfires toward the end of interglacial warm periods.

As we progress through the current glaciation period, the risk of large-scale extinctions due to wildfires is expected to increase, paralleling previous events such as the Karoo glaciation 251 million years ago. The Triassic period saw the widespread extinction of many land and shallow marine species, which paved the way for the age of the dinosaurs. This historical precedent underscores the potential for similar extinctions in the future if current conditions remain unchanged.

Conclusion

The history of forest fires shows that natural wildfires are a necessary and beneficial part of the ecosystem. Human intervention, particularly the proactive approach of extinguishing every wildfire, has led to increased fuel accumulation and more severe, long-lasting wildfires. Understanding the natural cycles of wildfires and adopting a more balanced approach to their management could help mitigate the risks they pose to both the environment and human populations.