Scientists from UCLA and Lawrence Livermore National Laboratory has confirmed that climate change is the main reason behind the growing amount of land which is destroyed by large wildfires in the western U.S. for nearly two decades.
Scientists has also assumed that this situation will get worsen in the coming decades. The data of U.S. Geological Survey says that from 1984 to 2000, the average burned area was nearly 2 million acres per year in 11 western states.
From 2000 to 2018, the average burned area was nearly 3.5 million acres per year. In 2020, the amount of land that was burnt by wildfires has reached over 9 million acres.
But the reasons behind these massive wildfires have been a subject of debate to researchers. Scientists think that human-induced climate change is the root cause behind it and also changing weather patterns, forest management and reduced summer rain has also played their roles behind this.
Researchers have applied artificial intelligence to climate and fire data to determine the main climate variable which is responsible for wildfire risk- vapor pressure deficit.
What is vapor pressure deficit?
VPD measures how much moisture the air can hold when the moisture is saturating back. When vapor pressure deficit is higher, the air draws more moisture form soil and plants. Where the vapor pressure deficit is higher, that area is prone to catch wildfires. These areas are mainly located away from urban areas.
Research has found that between 1979 and 2020, the vapor pressure deficit has increased in the U.S. is nearly 70% and the main reason behind this was human-caused global warming. The other 30% has been caused by naturally occurring changes in weather patterns.
The primary result of this research was these wildfires has been caused by human-induced reasons.
The researchers have also analysed the August Complex wildfire of 2020 and found out that human-induced global warming high VPD rate at the time when the wildfire begins.