Over the past two years, fires in the Amazon rainforest, California, and Australia have led to smoke traveling across the globe. Men and women often assume smoke from these fires only affects life in the immediate area, but nothing is further from the truth. This smoke now serves as a critical air quality issue thanks to climate patterns which are creating hotter, drier conditions. These conditions increase the risk of more fires and ones that burn for a longer period. More fires lead to more smoke, and the changing climate along with the pollution caused by these fires could bring about dangerous consequences, are wildfires getting worse? If so, why?
Wildfires have increased in the past few years, as many people noted. Researchers noted a few years ago that these fires were increasing in length and severity. Climate Central issued a report in June 2016 which explained the length of the wildfire season in the Western United States has increased in the past five decades. Back in 1970, the average length was under 150 days. By 2016, it lasted over 250 days.
Furthermore, the report stated the average size of a fire in this part of the country increased from less than .5 million acres in 1970 to almost two million acres in 2005. Roughly four million acres burned in 2007, while the country lost another three million five years later. A 2011 study blames these increases on global climate warming trends that make peak wildfire seasons hotter.
The researchers discovered a correlation between the severity of wildfires and the time at which snowpack melt. Early melts lead to more wildfires. What is a snowpack?
Snow builds up in cold climates and high altitudes. This melt remains around for months before it thaws and melts. When it does so, it provides fresh water that turns into rivers and streams in the spring and summer months. If a snowpack takes months to melt, the area receives needed humidity and moisture along with this fresh water, and this helps reduce the risk of ignition.
Any time one of the snowpack disappears, the water source dries until there is another big snowfall. The region dries out and the risk of wildfires increases. A small ember from someone’s cigarette or a lighting strike could lead to millions of acres going up in flames.
Global temperatures continue to rise which leads to melting occurring earlier and earlier. At the same time, this increase reduces local rain and snowfall totals. Fewer snow packs arise as a result, and less snow means snowpack that are smaller and less potent. What are the consequences of this?
When a snowpack melts over a period of months, high volumes of water make it into the air through evaporation. This water then condenses into humidity. When humidity levels rise, the risk of wildfires decreases. The moisture in the air keeps these areas damp, reducing this risk. Smaller snowpack and faster melts mean less humidity. Furthermore, the moisture from the snowpack melt sends water up into the air, which leads to rain or snow. Rain and snow both help to protect an area from wildfires, and any decrease is dangerous. Fewer snowpacks resulting from drier springs and winters means less evaporation and less snow and rain. In areas at high risk of wildfires, the risk ballons.
The Proceedings of the National Academy of Sciences (PNAS) conducted a 2018 study which confirmed these findings. They examined decades of fire data and concluded that smaller snowpacks lead to a higher risk of wildfires. The data covered hundreds of millions of acres in the country to ensure the scientists got an accurate picture of what is occurring and why.
They also examined the total amount of rain and the number of wildfires across the western United States between 1984 and 2015. The scientists found this has led to a vicious cycle, one involving climate change, less rainfall, a decrease in snowpack melt, and more severe wildfires. Reduced rainfall totals and more wildfires in the densely forested area result in larger wildfires that burn longer. When these wildfires occur, the length and intensity starts the cycle again. In addition, each fire adds chemicals and carbon pollutants to the environment, two factors associated with increasing global temperatures. Sadly, air quality in the western United States continues to decline because of these wildfires, and the problem isn’t limited to major cities.
Smaller suburbs in California which have better air quality are finding they are seeing the detrimental effects of these wildfires. In fact, when looking at the 30 most polluted regional cities in 2019, the IQAir Air Visual 2019 World Air Quality Report listed 25 of the 30 cities as California suburbs, including Diamond Bar, Compton, Ontario, and Eastvale. They state this is because of the severe wildfires seen in the state in recent years.
Natural Hazards and Earth System Sciences published a 2020 study which explained this cycle accounts for the Australian wildfires that took place in 2019 and 2020, fires that were among the deadliest and biggest in recent history. The researchers examined data available from climate data models, drought and heat patterns, and the Fire Weather Index. They discovered the average seven-day temperature highs across the globe for June and July 2020 have gone from 86 degrees Fahrenheit in the 1980s to roughly 95 degrees. This period stands as one of the major wildfire seasons and a time of extreme dryness.
Additionally, extreme heat waves have doubled in terms of their likeliness because of these increasing global temperatures. Australia witnessed extreme droughts along with record heat waves thanks to unusual temperature changes seen in the southern hemisphere during 2019. These factors came together and increased the risk of ignition and spread of wildfires in Australia. The fires scorched more than 12 million acres of land over a five-month period before firefighters could contain them fully.
These fires negatively impacted air quality in Australian cities. According to the 2019 World Air Quality report, cities in the country exceeded the safe limit by as much as 78 percent.
Why are wildfires lasting longer? Climate change makes wildfires worse, but they aren’t alone. Other major events impact the global ecosystem and increase the risk of wildfires. A study conducted in 2016 examined the relationship between human activity and wildfires, among other things. The researchers examined wildfire and climate date for the period from 1984 to 2015 and found that humans remain the leading cause of more intense and longer wildfires. Vehicle, fuel, and industry pollution lead to climate change and speed up increases in the global temperature. This has led to more drastic natural climate patterns. While some seasons are naturally warm and dry, human pollution sources make them drier and warmer.
Deforestation plays a role in wildfires as well. When they cut a forest or burn it down for economic development or agricultural purposes, bigger wildfires result. They burn out of control, sending tons of smoke into the air when they do. A single acre of vegetation absorbs billions of tons of carbon dioxide each year. In addition, it produces approximately a third of the globe’s oxygen supply. Fewer trees means oxygen levels decline and carbon dioxide levels increase. This leads to higher global temperatures and a heightened risk of wildfires.
Researchers also found other things contribute to more severe wildfires that last longer, and these causes exist thousands of miles from where the wildfires occur. Two research articles published in 2012 linked shrinking Arctic sea ice and higher global temperatures with a decrease in rain and snow across the globe. One article stated the thinning Arctic ice resulting from global warming makes it difficult for ice to form the following winter. The thick Arctic ice contributes to cool temperatures across the globe while encouraging more global rainfall in distant locations, such as in countries along the equator.
As the Arctic ice thins, temperatures warm and lead to a reduction in the amount of ice. This brings about even warmer temperatures that last year round. When this happens, less moisture makes its way into the air where it can become rain or snow. This results in another cycle of warming and drying that contributes to longer, more intense wildfires.
The second article examined Arctic atmospheric patterns for the period between 1970 and 2010. Researchers focused on the Rossby waves responsible for moving cool water and air from the Arctic to other areas of the globe. They noticed thinning ice combined with warming temperatures have reduce the amount of cold water and air making its way from the Arctic to places such as South America, Africa, and northern Australia.
This cool water and air remains critical in keeping the global climate balanced, especially in the cooling of areas by the equator that receive more UV light from the sun. When this cool water and air don’t make it to these parts of the globe, extreme weather events become more common, including floods, heat waves, and droughts. These events contribute to worsening wildfires.
Wildfires naturally occur and help keep the global ecosystem in check. However, rising global temperatures resulting from human activity have brought about wildfires that last for extended periods of time and are more severe. To reverse this trend, humans must alter their behavior. Industrial and traffic pollution must decline, which can be accomplished by relying on renewable energy sources that decrease carbon emissions. This will cause fewer fluctuations in global temperatures, as these fluctuations contribute to wildfires.
Furthermore, deforestation must slow and controlled wildfires need to occur once again. They help to protect forests and grasslands. Until they put these measures into place, wildfires will worsen. Humans must recognize this and take measures to protect themselves from the ill effects associated with the accompanying smoke and air pollution.