The air on Sylt was unusually thick this year

Climate change can trigger unforeseen chain reactions. The catastrophic forest fires in Canada this year are an example of this. The consequences are even being felt in distant regions - such as the vacation island of Sylt.

In many regions of the world, forest fires are practically part of the annual routine. However, the extremely severe and long forest fire season of 2023 surprised - and shocked - experts on several occasions. Canada in particular was hit particularly hard once again this year. The vast country in the north of America had already experienced some unprecedented forest fires in the past six years. Some of the smoke rose up to 20 kilometers into the sky like a volcanic eruption.

This summer was not the first time that plumes of smoke have spread from Canada to Europe. In this way, the forest fires on what is actually a distant continent are even affecting the air quality on German soil. On Sylt, for example, almost all of the peaks in particulate matter concentrations measured over the summer of 2023 are linked to the Canadian forest fires.

June 29 in particular stands out in the Federal Environment Agency's statistics. On this day, the smoke from the region around Quebec reached Germany after it had drifted over New York days earlier and then thousands of kilometers across the Atlantic. On the spa island of Sylt, of all places, it caused thick air and exceeded the particulate matter limit value.

An area of forest half the size of Germany has been burned

According to the Canada Wildland Fire Information Service (CWFIS), a total of 184,000 square kilometers of forest fell victim to the flames in Canada in 2023, an area half the size of Germany and more than twice as much as ever observed before.

The fires have also put many lives at risk. In August, for example, the city of Yellowknife with a population of almost 20,000 had to be evacuated for a whole three weeks due to a nearby wildfire. And at the beginning of June, New York City and large parts of the US East Coast were engulfed in thick smoke from forest fires raging in the Canadian province of Quebec. The images of New York covered in smoke and bathed in an apocalyptic-looking orange light went around the world.

But it is not only in North America that people are talking about a year of multiple environmental disasters: Worldwide, wildfires have raged more than twice as strongly this year, and for an exceptionally long time too. According to a press release from the Copernicus Atmosphere Monitoring Service (CAMS), Greece recorded the largest forest fire ever seen in Europe in August after weeks of extreme heat around the Mediterranean. At over 800 square kilometers, it was almost the size of Berlin. In comparison, the larger forest fire in June in Jüterbog, Brandenburg, with over 700 hectares (seven square kilometers) seems downright tiny. The dramatic forest fires on the Greek vacation island of Rhodes, which forced the evacuation of around 19,000 people, including many vacationers, are also unforgettable.

There was also a major forest fire in the USA this year, which gained sad notoriety. Fanned by a tropical storm passing close by Hawaii, it destroyed large parts of the town of Lahaina on the second-largest island of Maui in the state of Hawaii and claimed at least 115 lives.

Why are forest fires becoming more and more devastating?

In the northern latitudes in particular, there has been a clear trend in recent years towards ever more intense, hotter and therefore more destructive forest fires. Their smoke clouds are reaching ever higher into the atmosphere, in some cases up to the lower stratosphere, over 12 kilometers above the ground. Until now, this was only known to occur from major volcanic eruptions. Since the summer of 2017, however, such extreme forest fire events have become more frequent.

One reason for this is likely to be the general shift in climate zones, as the boreal coniferous forests of the Canadian and Siberian taiga are adapted to a cold climate with long snowy winters and short, cool summers.

However, the increasing marine heat waves in the northeast Pacific also play a decisive role. In particular, a recurring heat anomaly off the north-west coast of North America, which has become known as "The Blob" in recent years due to its distinctive shape, is increasingly causing extreme drought and heat in the north of the continent, to which nature is not adapted in many areas that are barely populated.

The incredible heat record of 49.6 degrees Celsius in Lytton, Canada, on June 29, 2021, located at the same latitude as Frankfurt am Main, is also related to this. A major forest fire also broke out there on the same day, almost completely destroying the small town.

According to CWFIS, around half of the fires in Canada are caused by lightning - so they are primarily a meteorological phenomenon. The significantly faster warming of the Arctic is also likely to play a role, as are local human activities, deliberate arson and inadequate forest management.

Fire accelerator for climate change

Researchers are very concerned about these developments. This is because the destructive power of forest fires has a long-lasting effect and poses many risks to the global ecosystem. For example, the forest fires in Canada alone resulted in additional emissions of around 480 megatons of carbon or 1760 megatons of CO2. This corresponds to more than three times Canada's industrial emissions in 2021 and around two thirds of the emissions of the entire EU.

Globally, CO2 emissions from forest fires reached a value of 7700 megatons of CO2 (2100 Mt of carbon) by December 10, placing them between the two largest industrial emitters, the USA (approx. 4800 Mt of CO2, 2021) and China (approx. 12500 Mt of CO2, 2021).

Global emissions from forest fires had previously fallen continuously and had reached the previous minimum of 1500 Mt of carbon in 2022. The year 2023 has now broken this downward trend and, on 10 December, ranks 8th out of 20 global emissions from forest fires since the start of the CAMS data series in 2003. Let's hope that this was just an outlier. Unfortunately, further forest fire extremes are to be expected in the future due to increasing global warming.

Graphics: Laura Stresing, Christoph Wolf