Unusually hot and dry conditions in parts of the northern hemisphere have been conducive to wildfires raging from the Mediterranean to the Arctic, says the World Meteorological Organisation (WMO).
Wildfires in Ontario, Canada. Image: Sentinel2 satellite via Copernicus EMS
Climate change, rising temperatures and shifts in precipitation patterns are all amplifying the risk of wildfires and prolonging the season. The northern part of the world is warming faster than the planet as a whole. That heat is drying out forests and making them more susceptible to burning. A recent study found Earth’s boreal forests are now burning at a rate unseen in at least 10,000 years.
In addition to the direct threat from burning, wildfires release harmful pollutants – including particulate matter and toxic gases such as carbon monoxide, nitrogen oxides and non-methane organic compounds. The particles and gases from burning biomass can be carried over long distances, affecting air quality in regions far away.
Wildfires also release carbon dioxide into the atmosphere, contributing to global warming. For instance, the 2014 megafires in Canada scorched more than seven million acres of forest, releasing more than 103 million tonnes of carbon into the atmosphere – half as much as all the plants and trees in Canada typically absorb in an entire year, according to a study by NASA.
The pristine Arctic environment, being particularly sensitive and fragile, is warming faster than most other regions. Particles of smoke can land on snow and ice, causing the ice to absorb sunlight that it would otherwise reflect, thereby accelerating warming in the Arctic. Fires in the Arctic also increase the risk of further permafrost thawing that releases methane, which is also a greenhouse gas.
The WMO’s Global Atmosphere Watch (GAW) Programme highlights the risks and explains how advances in satellite technology can make it possible to detect and monitor fire dangers. Improving forecasting systems is important for predictions and warnings around fire danger and related air pollution hazards.
Heatwaves fuel fires
Since the start of June, the Copernicus Atmosphere Monitoring Service (CAMS) has tracked more than 100 intense and long-lived wildfires in the Arctic Circle. In June alone, these fires emitted 50 megatonnes of carbon dioxide into the atmosphere – equivalent to Sweden’s total annual emissions and more than was released by all Arctic fires in the same month between 2010 and 2018 combined.
Although wildfires are common in the northern hemisphere between May and October, the latitude and intensity of these blazes, as well as the length of time they have been burning, has been particularly unusual, according to CAMS Senior Scientist and wildfires expert, Mark Parrington.
The ongoing Arctic fires have been most severe in Alaska and Siberia, where some have been large enough to cover almost 100,000 hectares, or the whole of Lanzarote. Fires in Alberta, Canada have so far consumed more than 830 000 hectares to date, while smoke from massive wildfires near Ontario is producing large amounts of particulate matter, affecting air quality.
In Alaska, CAMS has registered almost 400 wildfires this year, with new fires igniting every day. The heatwave in Europe at the end of June also triggered wildfires in a number of countries, including Germany, Greece and Spain.
The average June temperature in the parts of Siberia where wildfires are raging, was almost ten degrees higher than the long term average between 1981 and 2010. Temperatures in Alaska hit record highs of up to 90°F (32°C) on July 4, fuelling fires in the state, including along the Yukon River along the Arctic Circle.
CAMS, which is implemented by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the EU, incorporates wildfire observations from the MODIS instruments on NASA’s Terra and Aqua satellites into its Global Fire Assimilation System (GFAS). This allows it to monitor the fires and estimate the pollutants they are emitting. It assimilates fire radiative power observations from satellite-based sensors to produce daily estimates of biomass burning emissions, which are part of the extensive measurements performed by the GAW Programme. These measurements are essential for forecasts, research on atmospheric composition and to develop warning systems.
In view of the risks, WMO has initiated a Vegetation Fire and Smoke Pollution Warning and Advisory System to develop, implement and harmonise fire forecasting across the globe, providing a better picture of fires and related impacts and hazards everywhere. The Southeast Asia Regional Centre, operated by the meteorological service of Singapore, is already producing forecasts.
This article was published on the WMO website and is reproduced under Creative Commons licence.