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Newsflash Reading 07/07/2020

The Copernicus Climate Change Service (C3S) reports today that global temperatures for June were on par with 2019’s record temperatures for the same month. But the most striking regional feature was exceptional warmth over Arctic Siberia, where average temperatures reached as high as 10 °C above normal for June. The temperature averaged over all land in Arctic Siberia combined was more than 5 degrees above normal, and more than a degree higher than in 2018 and 2019, the two previous warmest Junes.

For May, C3S, which is implemented by the European Centre for Medium Range Weather Forecast (ECMWF), reported on a long period of warmer than average temperatures across western Siberia, starting as early as December 2019. In June, however, western Siberia saw mainly below average temperatures, illustrating the large variability across the vast Siberian region. Meanwhile, it was in eastern Siberia where C3S estimated a maximum hourly Arctic temperature of 37 °C on 20th June, in the area where a station-based record temperature of 38 °C was reported for the same day, though the value is yet to be confirmed by the World Meteorological Organisation. The new record maximum hourly ERA5 temperature for June is 1-2 °C warmer than earlier record estimates in the Arctic, which were for days in 1969 (in Alaska) and 1973 (in eastern Siberia).

Director of the Copernicus Climate Change Service (C3S) at ECMWF, Carlo Buontempo, comments: “Finding what caused these record temperatures is not a straightforward endeavour as there are many contributing factors interacting with each other. Siberia and the Arctic Circle in general have large fluctuations from year to year and have experienced other relatively warm Junes before. What is worrisome is that the Arctic is warming faster than the rest of the world. Western Siberia experiencing warmer-than-average temperatures so long during the winter and spring is unusual, and the exceptionally high temperatures in Arctic Siberia that have occurred now in June 2020 are equally a cause for concern.” 

One contributing factor to both the mild winter and spring temperatures over western Siberia, as well as the high summer temperatures over Arctic Siberia, was different but relatively persistent large-scale wind patterns. C3S data further indicate that snow cover and surface soil moisture reached record lows for June over the Siberian Arctic in June 2020. These are also factors, which likely played a role in the unusually high temperatures reached in the region.

Besides, the lower-than-usual soil moisture is believed to have been a contributing factor to increased fire activity, mostly concentrated in the far north-east of Siberia. Scientists from the Copernicus Atmosphere Monitoring Service (CAMS), also implemented by ECMWF, have been monitoring wildfire activity since the start of the boreal fire season in early May. The number and intensity of wildfires in the Sakha Republic and Chukotka Autonomous Oblast and, to a lesser degree, parts of Alaska and the Yukon Territories, have been increasing since the second week of June and have resulted in the highest estimated emissions in the 18 years of the CAMS dataset. For June, an estimated total of 59 megatonnes of CO₂ were released into the atmosphere, which is more than last year’s June total of 53 megatonnes of CO₂. 

CAMS Senior Scientist and wildfire expert at ECMWF, Mark Parrington, comments: “What is remarkable with these fires in Siberia is the striking similarity with what we saw over the same period of last year in terms of both the area affected and the scale of the fires. Last year was already by far an unusual, and record, summer for fires in the Arctic Circle in our Global Fire Assimilation System dataset, which goes back to 2003. This year has evolved in a very similar way and if it continues to progress like last year, we could see intense activity for the next few weeks.”

“Higher temperatures and drier surface conditions are providing ideal conditions for these fires to burn and to persist for so long over such a large area. We have seen very similar patterns in the fire activity and soil moisture anomalies across the region in our fire monitoring activities over the last few years,” he added.

June 2020 surface air temperature:

• June 2020 was on a par with June 2019 the warmest June in the record, at 0.53°C above the 1981-2010 average,
• during both June and averaged over the last 12 months, Siberia stands out as the region with the largest anomalies,
• Europe saw temperatures that were far above average in the north and below average in the south,
• overall, it was the joint second warmest June for Europe

The temperature map and quoted data values are from ECMWF Copernicus Climate Change Service’s ERA5 dataset, currently dating back to 1979, values for 1950 to 1978 are from a pre-release version of the dataset. Area averages for temperature over the European region are for land only with the following longitude/latitude bounds: 25W-40E, 34N-72N. Area averages for temperature over the Arctic Siberian region are for land only with the following longitude/latitude bounds: 60E-180E, 66.6N-90N.

More information about climate variables in June and climate updates of previous months as well as high-resolution graphics can be downloaded here:

https://climate.copernicus.eu/monthly-climate-bulletins

More information on the mild winter and spring in Siberia can be found here:

https://climate.copernicus.eu/investigating-unusually-mild-winter-and-spring-siberia