06.08.2018
Copernicus: Heatwaves and wildfires: climate change or not?
As many parts of the world are suffering under extreme heatwaves and many wildfires are spreading across Scandinavia and Greece, people are quick to point a finger at climate change, whereas the full explanation is not that simple. The Copernicus Climate Change Service (C3S), implemented by the European Centre for Medium-Range Forecasts (ECMWF), provides the information and data that can help place these events in the context of a changing climate.
CAMS Surface analysis showing the dispersion of particulate matter (PM10) from the fires in Attica to the surrounding region at 06:00 on 25 July 2018.
Quelle: Copernicus Atmosphere Monitoring Service, ECMWF
The maps and graphs produced by C3S have often been used in the media to try and make sense of the current weather situation. However, it is never easy or even possible to attribute ‘single’ weather events to climate change. So called attribution studies try to quantify this. C3S is in the initial stages of setting up a pilot scheme that aims to perform the necessary climate attribution calculations within a week of specific weather events. This pilot scheme is scheduled to begin in 2019.
The surface temperature map does clearly show that across Asia (especially Japan), northern Europe, the US and Canada, temperatures during the first three weeks of July have been much higher than the average temperatures for those weeks over the 1981-2010 period, a commonly used reference period. For the final week of July the weather forecasts showed a likely continuation of the heatwave in northern Europe, making it probable for further temperature records to be broken in these areas this summer. However, just because temperatures are high now, it does not mean that temperatures will always be above the long-term average in the years to come.
As Freja Vamborg, senior scientist at C3S, mentioned in an interview on Euronews: “We should stress that there is a lot of variability in the European weather: just look at the first summer months, where there have been big differences with certain regions suffering from torrential rains and floods (such as in the Balkan area), whereas others experience droughts, wildfires and extreme temperatures. Or look back earlier in the year, with an unusually cold March in many parts of Europe.”
With extreme dry conditions also comes the risk of extensive wildfires, as are being experienced in Greece and throughout the Scandinavian peninsula. Wildfire risk depend on several contributing factors, such as available amount of dry foliage, temperature, overall soil moisture, wind speed and the presence of potential ignition sources (which can be natural, such as lightning, or human-related, such as a piece of glass or a smouldering cigarette). Data from the Copernicus Emergency Management Service (CEMS), supported by ECMWF, already in June showed a very high danger of fires in northern Europe and this will continue for the next few weeks.
Maps from the Copernicus Atmosphere Monitoring Service (CAMS), also implemented by ECMWF, clearly show the spread of smoke and pollution emitted by wildfires across the affected regions. The CAMS forecasts, which use estimates of fire emissions based on satellite observations with the Global Fire Assimilation System (GFAS), have been used to accurately predict the spread of pollutants, such as particulate matter from the fires, which can impact the surface air quality across the region.
Having put these current events in the backdrop of a changing climate, can we expect more of these events in the future?
Vamborg confirms: “With climate change, we do indeed expect these kinds of heatwaves to occur more often. When it comes to droughts and wildfires it is more complex, as their occurrence depends on other factors than just high temperatures.”
Read this and more at Copernicus’ website