Wildfires are a natural occurrence in many parts of the world, making it difficult to attribute any single wildfire solely to climate change. Other factors, such as changes in land use, can also play a role in their occurrence. Yet, scientists agree that climate change and wildfires are deeply connected and climate change is increasing the likelihood of weather conditions that are favorable for wildfires.
Climate change would bring about significant shifts in the geographical distribution of existing ecological domains, placing additional stress on vegetation structure and composition. Consequently, vegetation would become more susceptible to wildfires due to increased vulnerability. In recent decades, the wildfire season has extended by approximately three and a half months compared to previous times.
Wildfires can have profound and detrimental effects on both society and the environment. This forest loss has serious environmental and economic consequences, including the loss of livelihoods of forest-dependent communities and peoples, water scarcity, destruction of habitats for endangered species, and increased greenhouse gas emissions, which contribute to climate change and wildfires.
In recent times, exceptionally high temperatures have combined with minimal precipitation and reduced snowpack and resulted in extreme and highly severe climate change and wildfires. It is anticipated that the size, frequency, and severity of wildfires will intensify in the coming years.
Extended periods of extreme heat progressively deplete moisture from both the ground and vegetation. As temperatures soar, more moisture evaporates from the soil and vegetation, causing trees, shrubs, and grasses to dry out. This process also transforms leaf litter and fallen branches into highly flammable fuel, enabling them to spread rapidly, especially in the presence of strong winds.
Wildfires have a profound impact on the landscape and ground conditions, increasing the likelihood of flooding during heavy rainfall. This occurs because the burned ground loses its ability to absorb rainwater, resulting in runoff. As temperatures rise, the atmosphere can hold more moisture, leading to increased droplet formation and heavier rainfall. This can result in more intense and larger rainfall occurring over a smaller area and within a shorter time frame.
Droughts create optimal conditions for wildfires to thrive. Insufficient rainfall and low humidity cause trees and vegetation to dry out, creating abundant fuel. In such conditions, even a small spark from lightning, electrical mishaps, human mistakes, or intentional fires can rapidly escalate and become uncontrollable. Thus, evidence suggests that drought, in conjunction with forest productivity, topography, fire weather, and management practices, plays a significant role in influencing the intensity, severity, extent, and frequency of wildfires.
The relationship between drought and fire is undoubtedly intricate and multifaceted. In the short term, increased droughts are likely to result in more fires as vegetation becomes dry. However, in the case of prolonged droughts, such as megadroughts, the potential for fire may decrease. This is due to diminished vegetation growth and the eventual depletion of available fuel.
Forest fires are releasing significant quantities of greenhouse gases and particulate matter into the atmosphere. In fact, wildfires are responsible for emitting about 6-8 billion tons of carbon dioxide, which is equivalent to up to 20% of global CO2 emissions. This amount is equal to the emissions caused by global transportation.