Canada wildfires May/June 2025

And a global scale report

During late May and June 2025, the Canadian provinces of Manitoba and Saskatchewan declared states of emergency due to a series of wildfires. The blazes prompted the evacuation of more than 25,000 people. The intense fires also sent hazardous smoke towards the USA. In total over 200 wildfires burnt across Canada, and just over half were uncontrolled. Collectively, they burned more than 2 million acres. The Canadian Armed Forces began moving people out of endangered remote communities and supported firefighting efforts.

The Shoe and Camp fires in Saskatchewan, Canada, May 10, 2025 (Source: NASA)

By early June, smoke from the Canadian wildfires had travelled over 8,000 km across the Atlantic Ocean, extending all the way to parts of Russia (See Figures 1 and 2). Smoky skies have been experienced by several regions, including the Arctic archipelago and western Greenland. The transport of extensive plumes of smoke also affected the colour of sunrises and sunsets in the UK and Ireland. In Canada and the United States, moderate-to-high levels of smoke continued, deteriorating the air quality in parts of Illinois, Iowa, Michigan, Indiana, and Wisconsin, as well as Ontario and Quebec, Canada.

Figure 1.

Source: NASA

The satellite image below (Figure 2) shows smoke from fires burning primarily in the Canadian provinces of Saskatchewan and Manitoba. The plumes extend to the north-northeast across Nunavut toward the coast of Greenland and southward across the United States.

Figure 2

Source: NASA

Smoke from the fires burning in Canada raised health concerns as airborne particles degraded air quality locally and in several U.S. states. In Michigan, officials issued an air quality advisory on May 30, noting that the air could become unhealthy for sensitive groups.

Pyrocumulonimbus clouds (pyroCb).

According to the Copernicus Atmosphere Monitoring Service (CAMS), the fires resulted in the development of pyrocumulonimbus clouds (pyroCb). PyroCb clouds typically form when a wildfire burns with exceptional heat and intensity, generating enough thermal energy to push smoke, ash and moisture high into the atmosphere from where powerful jet streams can transport the smoke over long distances.

The May-early June 2025 total estimated wildfire carbon emissions for Manitoba, Saskatchewan and Alberta are significantly higher than average. For Manitoba, the total estimated fire emissions up to 2 June are the highest on record by a considerable margin at around 13 megatonnes of carbon – about 3 times the previous highest for the same period in 2023, and for Saskatchewan the second highest, only after 2023 (see Figures 3 and 4 below).

Figure 3.

Emissions from Canada's wildfires are spiking again

This chart shows the annual growth of wildfire emissions in million tons of carbon dioxide, from 2003-2005. 2025 data ends on June 9.

As of June 9, the 2025 emissions are higher than those during most full years in this dataset, which goes back to 2003. And the traditionally busiest part of the fire season has not even arrived yet, typically falling later in the summer.

Figure 4

Daily total fire radiative power (top) for Alberta, Saskatchewan and Manitoba in May, comparing 2025 (in red) with the 2003-2024 mean (in grey) and total estimated carbon emissions (bottom) for the three provinces in May. Source CAMS

Global scale forest loss
Wildfires are responsible for almost half of the record-breaking tropical forest loss in 2024, according to the World Resources Institute. In 2024 alone, global tropical primary forest depleted at a rate equivalent to the area of the size of Panama. This caused 3.1 gigatonnes (Gt) of greenhouse gas emissions, slightly more than the annual CO₂ emissions of India's fossil fuel use.

Brazil, Bolivia, and the Democratic Republic of the Congo (DRC) were the countries with the most forest loss in 2024. Brazil experienced its most intense and widespread drought in 70 years, accounting for 42% of global primary forest loss across the tropics. Research shows fires in Brazil's wetlands are now 40% more intense due to climate change. Outside of the tropics, boreal forests also experienced unprecedented tree-loss, with both Canada and Russia losing 5.2 million hectares of forest.