EUROPE – Wildfires have been spreading across central Russia and Siberia since spring, sending smoke into the skies and filling the air with pollutants. During the first two weeks of July, smoke from fires in the Sakha Republic of Russia travelled an astonishing 9500 km – across the Arctic Ocean to Alaska and North-West Canada and eventually the west coast of Greenland. This long-range movement of smoke was predicted five days in advance by the Copernicus Atmosphere Monitoring Service (CAMS).
The CAMS Global Fire Assimilation System (GFAS) estimates that between 2003 and 2017 Russian wildfires emitted on average about five mega tonnes of carbon dioxide into the atmosphere per day. At the end of June this year, the fires suddenly increased in intensity, upping their carbon dioxide output to approximately 20 mega tonnes per day. This isn’t particularly unusual – wildfires are common across Siberia in the summer months, and we have seen more intense ones in the past. But what is intriguing is how far such a huge amount of this smoke has been transported across the Arctic.
CAMS provides a variety of information on the atmosphere to a wide range of users. It also creates daily forecasts of atmospheric composition using models of the atmosphere. Using its atmospheric models, CAMS was able to predict the journey that the smoke would make before it was later observed by satellites and ground-based detectors. On 4 July CAMS predicted that the wildfire smoke would travel from central Russia to arrive at Alaska and North-West Canada on 6 July.
The smoke arrived in Alaska on the forecasted date and has been making its way eastwards since then. As it crossed Canada, the smoke was detected by several ground-based measuring sites, confirming CAMS predictions of its journey.
This is not the first time CAMS data have been used to monitor wildfire smoke In the Arctic; last summer there was a similar event of long-range smoke movement from fires in British Columbia and Northwest Territories, Canada, and in 2015 smoke from wildfires in Alaska was observed in the European Arctic.
High-latitude wildfires are of particular interest because they significantly affect the composition of the atmosphere in the generally pristine environment of the Arctic, potentially affecting climate change there. Wildfires increase emissions of greenhouse gases and pollutants. Their smoke is an example of an aerosol – a specific type of pollutant made up of tiny particles suspended in the atmosphere.
Particles of smoke can land on snow and ice, causing the ice to absorb sunlight that it would otherwise reflect, which contributes to global warming. Furthermore, increased aerosols in the atmosphere can absorb and reflect light and lead to surface cooling during the day.