Climate change. Canada’s boreal forest is far north. Most parts of it only reach 64F (18C) averages in the heat of the summer. Its density and climate also means it gets very little evaporation compared to its rainfall, and is subject to frost 9 months of the year, and heavy fog the rest of the time. This kept this biome very humid, kept soil damp, and left most of the low level foliage coated in dew all day long. Some parts of the forest even had thick levels of permafrost beneath the topsoil that on rare hot days would seep water back into the ecosystem. Just as many wildfires started by lightning strike in previous decades as now. The difference is they struggled to catch and spread in this damp environment. Now extreme dry weather, record breaking heat, northern thaw, erode that protective moisture barrier, leaving the boreal forest vulnerable especially in the more southern parts. Boreal forests previously went through this process naturally when an over density caused a drier environment you’d get high-intensity crown fires that were cyclical. Every 50-200 years depending on region. Now we get them annually. Boreal forest fires are much more severe than others too. The long history of cyclical burns means the soil contains charcoal, the thick multi-layer foliage adds fodder and causes the fire to spread quickly, and pine, spruce, and aspens are all some of the trees with both the most density and the best for wood burning. It results in towering forest fires of immense heat and rapid spread. These forests are denser than anything else in North America or Europe, and the current fire in Ontario alone, is the same square mileage as the entire state of Delaware. From the time it ignited, to covering that size, took less than 20 hours. While some in the US still think climate change is a hoax, we are all going to deal with the consequences of it, as we’ve turned the largest forest in the world into a tinder box, and fires in less than 0.01% of it drowns the entire continent in smoke.