World wildfires –rise or decline?

Currently we are witnessing an alarming trend of wildfire breakout in the areas in the world where they have never originated.

What is the current wildfire pattern on Earth? Is the situation getting really worse? Unfortunately, the answer is “yes”, moreover, wildfires start originating in the areas where they have never been witnessed before.

The main reason of it lies in the fact that some dangerous trends responsible for wildfire breakout are overlapping and feeding off each other. Among them, there are:

• Further development of industry and transport together with some other human activities result in the rise of carbon emission;
• Deforestation leads to decline in both absorbing carbon dioxide and oxygen production by plants and trees;
• The increase in carbon dioxide and other greenhouse gases leads, in turn, to further temperature rise globally;
• further temperature rise in the world causes less humidity and less rains;
• more arid and hotter climate helps contribute earlier melting of snow cover, which results in less humidity in fire-hazardous areas;
• The global temperature rise has already caused melting of arctic glaciers.

After analyzing the statistical data and scientists’ reasons, we can come to a conclusion –wildfire season has increased by as much as 105 days comparing with the early 1970-s, an average wildfire area covers up to 4 million acres now and global warming and carbon emissions are on a rise.

But should those who live in the areas where there are no wildfires worry about them? Are we witnessing a global rise in wildfire numbers?

According to the scientists’ forecasts, the number of extreme wildfires will rise globally by 14% up to 2030, by 30% up to 2050, and by 50% up to 2099. (1)

Sharp increase in wildfire numbers has already been marked in forest areas, and their catastrophic damage continues to grow.

Wildfire smoke covers much larger territories than you may ever think of. It’s not limited by the area close to the fire itself.

In 2019-2020, wildfires in the Amazon area, as well as in California and Australia saw their smokes spread over oceans and continents across thousands of miles.

The higher the number of wildfires is, the larger is the smoke spreading around. The research of wildfire smoke is becoming more and more important in air quality studies. In the USA, wildfires resulted in generation of 25-50% atmospheric PM 2.5 by the end of 2021(2). These particles provoke chronic diseases and early death from respiratory illnesses, heart problems and cancer.

Air pollution resulted from weeks-long wildfires combining with global climate change is leading to dangerous consequences.

Researchers are witnessing clear increase in the duration and strength of wildfires. In June 2016, Climate Central published a report noting that the average length of the wildfire season in the Western US has increased by 105 days in comparison with 1970-s - from under 150 to over 250 days. (3)

Moreover, the area burnt by wildfires in the USA saw an annual increase of 192 thousands of acres from 1991 to 2020.

According to an earlier research, global warming results in hotter peak seasons of wildfires and earlier melting of snow cover. (4)

Snow cover is huge snow accumulation generated in cold climate and at high altitudes; it makes months for it to melt. It’s also a valuable source of fresh water, which turns into streams and rivers as it melts. Snow cover melting means bringing water to areas covering many hundreds of miles, without which they would be dry and hence more vulnerable to ignition. What is more, large volumes of such water can evaporate and condense in the air, raising its humidity.

When the snow cover has melted completely, this valuable source of water disappears till the next huge snowfall. As a result, the area becomes drier and more vulnerable to wildfire breakouts either from natural factors, e.g., lightning strikes, or human irresponsibility, e.g., unstubbed cigarettes or improper use of fire.

Increase in the surface temperature on the planet results in larger numbers of hot days and their earlier coming, which, in turn, leads to faster melting of snow cover and less rain and snow. The fact is that snow and rain form snow cover –and the less the volume of precipitations is, the thinner and weaker is the snow cover.

The less snow cover is and the fewer the days of its melting are, the less is the humidity of the area – and it’s nothing but humidity that is able to protect the area from wildfires. What is more, water generated after snow cover melting helps form clouds responsible for rain or snow. The less the snow cover after a drier winter and spring season is formed, the less is the amount of water able to evaporate and rain back down to the area; this water becoming an important key to wildfire prevention.

Thus, wildfire risks in dry areas, which already are in high risk zone, can be multiplied.

Proceedings of the US National Academy of Sciences (PNAS) published in 2018 confirm the relationship between less volume of snow cover and higher risks of wildfire breakouts on the basis of decades-long correlations between wildfire numbers and the area of burnt territories measured in millions of acres. (5)

Scientists analyzed and compared the total amount of rain and the number of wildfires in the Western US from 1984 to 2015. The research confirmed the vicious cycle of climatic changes, less rain, fewer days of snow cover melting and stronger wildfires. The less rain and the more the number of wildfires in thick forests is, the more is the area of new wildfire breakout and the longer such wildfires last. As a whole, it results in air pollution with carbon and chemicals, which, in turn, leads to even higher temperatures on our planet.

The figures from the 2019 World Air Quality Report made by IQAir AirVisual, show that wildfires in California brought small Californian suburbs, previously regarded as ecologically stable, into the Top-30 or even Top-25 of the most polluted towns in 2019.

The research published in «Natural Hazards and Earth System Sciences» in 2020 proves it is the climate change that is responsible for one of the largest and deadliest wildfires in the modern history – the Australian wildfire of 2019-2020 (6).

After exploring a large dataset of the Fire Weather Index and the structural changes of heat and drought, researchers found out that:

• Global average temperature in 7-day peaks in June – July (which is one of the main seasons of wildfires, and the period of maximum dryness as well) rose from 30°C (86°F) in 1980 to almost 35°C (95°F) in 2020;
• Global warming doubled the risk of extreme heatwaves;
• Highly irregular temperature changes in the Southern hemisphere in 2019 resulted in record heatwaves and extreme drought in Australia.

All these factors paved the way for the largescale breakout of wildfires in Australia, which lasted for 5 months and burnt over 12 million of acres of land.

It’s been identified that in Australian cities affected by wildfires, PM 2.5 exceeded the safe limit of 10 µg/m3 by 78%, according to the 2019 World Air Quality Report.

It has long been known that Indonesia, Argentina and South Europe are also vulnerable to wildfires despite their humid climate (7). But recently, large territories in Western Canada, Northern and Central Europe and Siberia were also exposed to wildfires and their harmful effects. The latter regions belong to the area with much colder climate, and wildfires broke out there much less often (8).

Not only the climate change is making the wildfire pattern worse; there are also other factors leading to increase in wildfire numbers.

Researchers who studied the data on wildfires from 1984 to 2015 conclude that human acitivity has become the main reason for deterioration of the wildfire pattern worldwide(9). Climate changes resulted from industrial, transport and other anthropogenic pollution are accelerating the rise in global temperatures and contributing to sharper weather changes. Wet and dry seasons are becoming even wetter and drier, and vice versa.

Population growth and increase of wildland-urban interface have led to the higher number of wildfires caused by humans and longer period of burning as well.

One of the key factors that makes the wildfire situation even worse is deforestation. Forests are often cut or burnt for agricultural and other economic purposes. Deforestation leads to even stronger and out-of-control wildfires that result in emitting of many thousands of tons of smoke into the air.

Meanwhile, plants and trees covering only one acre of the land absorb up to 2.4 billion tons of CO2 from air (10) (11). The less the number of trees is, the less oxygen is produced by them and the higher is the CO2 level, which, as if in a vicious cycle, leads to more and more wildfire breakouts.

Scientists have also revealed influence of the Arctic ice melting on the number of wildfires worldwide.

The influence between the Arctic ice melting and the number of global wildfires was identified on the basis of long-term data analysis of shrinking ice in the Arctic, global warming, global amount of snow and rainfall and how this latter index is falling.

In 2012 Springer Link published an article showing how the ice shrinking in the Arctic, which had already resulted from the global warming, makes it more difficult for ice to generate again during the following winters (12). A well-known fact is that the Arctic ice helps cool the planet and contributes a lot to the amount of global precipitations, including those in the equator zone. But as the Arctic ice is becoming thinner due to the global warming, there arises a vicious cycle – less amount of ice results in higher rise of temperatures and less amount of precipitations, which, in turn, leads to further ice thinning, etc. All this contributes to the alarming trend of global warming and droughts.

Another article published at the same time focuses on the Rossby waves that deliver cold Arctic air to other parts of the globe (13). Having analyzed the data from 1970 to 2010, researchers concluded that both higher temperatures and the Arctic ice thinning had resulted in less volumes of cold air and water spreading from the Arctic to the Central and South America, Africa, Southern Asia and northern Australia. As the cold air and water delivered by the Rossby waves are the key factor to help balance the world climate by cooling equator zones that are most vulnerable to the ultraviolet radiation, their less amount results in higher numbers of extreme natural events. Simply put, droughts, floods, cool and heat waves occur more and more often, and all this results in deterioration of the wildfire pattern.

Researches show that the amount of extreme wildfires with their catastrophic consequences for both the environment and people will only keep growing.

To reverse this highly alarming trend it’s necessary to reduce industrial and transport pollution and decrease the amount of carbon dioxide emitted into the air by larger use of renewable energy sources. Significant reduction of carbon dioxide will help stabilize global temperatures and decrease the number of wildfires.

It’s also highly necessary to replace deforestation introducing afforestation instead and reduce the number of controlled wildfires.

In addition, personal precautions should be observed and information about it should be widely shared. Regardless of how far you are from the wildfire area, it’s necessary to remember that the smoke spreading from wildfire areas can be harmful and it’s necessary to observe all precaution measures, which include:

• Air quality monitoring to determine when the level of smoke may become dangerous;
• Use of air purifiers both indoors and in vehicles;
• Mask wearing outdoors in case of dangerous smoke.

About IQAIR

• IQAIR is a Swiss technological company that helps people, organizations and governments improve air quality by sharing information about it and spreading cooperation.
• [1] World Metrological Organization. (2022). Number of wildfires forecast to rise by 50% by 2100.
• [2] Wibbenmeyer M, et al. (2021). Wildfires in the United States 101: Context and consequences. Resources for the Future.
• [3] Climate Central. (2016). Western wildfires: A fiery future.
• [4] Holden ZA, et al. (2011). Wildfire extent and severity correlated with annual streamflow distribution and timing in the Pacific Northwest, USA (1984-2005). Wiley Online Library. DOI: 10.1002/eco.257
• [5] Holden ZA, et al. (2018). Decreasing fire season precipitation increased recent western US forest wildfire activity. PNAS. DOI: 10.1073/pnas.1802316115
• [6] Van Oldenborgh GJ, et al. (2020). Attribution of the Australian bushfire to anthropogenic climate change. European Geosciences Union.
• DOI: 10.5194/nhess-2020-69
• [7] Penney V. (2020). It’s not just the West. These places are also on fire. The New York Times.
• [8] European Environment Agency. (2021). Forest fires in Europe.
• [9] Abatzoglou JT, et al. (2016). Impact of anthropogenic climate change on wildfire across western US forests. PNAS. DOI: 10.1073/.1607171113
• [10] International Union for Conservation of Nature. (2017). Issues brief: Deforestation and forest degradation.
• [11] Stouncil JM. (2019). The power of one tree – the very air we breathe. U.S. Department of Agriculture.
• [12] Stroeve JC, et al. (2012). The Arctic’s rapidly shrinking sea ice cover: A research synthesis. Springer Link. DOI: 10.1007/s10584-011-0101-1
• [13] Francis JA, et al. (2012). Evidence linking Arctic amplification to extreme weather in mid-latitudes. American Geophysical Union. DOI: 10.1029/2012GL051000