Thousands of Nova Scotians fleeing north of Halifax, communities evacuated or on edge across B.C. and Alberta — the 2023 wildfire season has come harder and earlier than many Canadians are used to.
The global intensification of fire weather Canada is warming two to three times faster than the global average. That's partly because of its northerly position on the Earth's surface. At the same time, it's almost entirely due to humans' continued practice of burning fossil fuels. A 2021 study from scientists at Natural Resources Canada examining global extreme fire weather between 1979 and 2020 found decreasing relative humidity drove up the fire weather index by 14 per cent and a measure of initial spread by 12 per cent."These trends are likely to continue, as climate change projections suggest global decreases in relative humidity and temperature increases that may increase future fire risk where fuels remain abundant," concluded the researchers.
In places without a significant snow cover, the fire season starts when mean daily temperatures hit 6 C for three days straight — the lower temperature limit plants need to grow. Of those, half the census divisions were among the top 10 slices of the country with the highest per capita rates of premature death. That includes the town of Nelson, B.C., where persistent summer smoke led at least one doctor to clinically diagnose a patient with climate change in 2021 — likely a global first.