From the beginning of January, from Russia to Siberia, the Eurasian continent is unusually cold. Western Russia experienced a frosty weekend with only -29°C in the Moscow region, while Siberia fell below -60°C, a record for January, on Tuesday. How to explain such a cold wave in the context of global warming?
Siberia is a vast area stretching more than 3,000 km east of Moscow. Suffice it to say that, as seen from Oymyakon, the world’s coldest city in Eastern Siberia, Moscow appears to be in the west of the continent with an almost temperate climate.
Siberia: a cold hell
Every winter, Siberia is used to experiencing extreme values. In Yakutia, the coldest region, the average temperature in January is -45°C. This makes it the coldest area in the northern hemisphere, with some areas in northwestern Canada. It is also the 2nd coldest region on the planet in winter after Antarctica. However, the climate is very contrasting between winter and summer, with annual temperature variations reaching 80°C. In fact, short bursts of heat can raise temperatures to 35°C in these sectors, which are -60° in winter.
A cold snap on the Eurasian continent
Wave #cold in #Siberia beats #records (monthly record with -62 ° C in Jilin). In some places, this is the strongest cold snap for January since the 1960s. Anomaly drops to -30°C which is stronger than the warm anomalies mentioned 🌡️ https://t.co/hJHNOfHdWO
— The Weather Channel (@lachainemeteo) January 10, 2023
Every winter in Eastern Siberia, temperatures range from -50° to -55°C during the long arctic night, while temperatures do not exceed -30 to -40°C in the pale glow of a frosty day. However, since the beginning of January, the great cold has spread to almost all of Eurasia, from Moscow to Yakutia. The negative anomalies recorded in the heart of Siberia fell to -30°C more than the warm anomalies observed on our planet. Overall, the current temperature across Siberia makes it the strongest cold wave in Yakutia since 1982. But the minimum and maximum temperatures (-57°C at night, -50°C during the day) make it the strongest cold wave since 1994. Finally, -62°C recorded on Tuesday is a monthly record for Jilinda. station (since the opening of the current weather station in 1942).
Absolute cold records in Siberia are not under threat to date: -64 ° C in the Jilinda region, Batamay -65.7 ° C, Ulakhan Kyuel -65.2 ° C, Iema -65.0 ° C, Verkhoyansk -63.0 ° C , -62.1 °C Oymyakon, e.g. The cold record that can be found in the archives in Russia dates back to January 26, 1926 with -67.8 ° C in Oymyakon and Verkhoyansk.
How to explain such a cold anomaly?
It may seem counterintuitive to observe such cold anomalies, which are also particularly intense in the northern hemisphere this winter during global warming. America’s Christmas chill dropped below 20°C on average, but only briefly. The current cold wave in Siberia is 30°C below average, so much so that weather maps no longer have the appropriate color. Conversely, warm anomalies are very widespread and long-lasting (often +10° to +14°C in North America as well as China today). Therefore, the contrasts are greater in the northern hemisphere and more moderate in the southern hemisphere.
Mechanistically, the fluctuations of the jet stream are responsible for the coupling effects of the basins that transport temperate air to the north and cold air to the south. But this is not enough. There are also fluctuations in the tropopause, the layer that limits the troposphere in which we live and the stratosphere above. Variations in this boundary layer are capable of sinking the icy air of the stratosphere towards the ground. This principle is known in the media as the “polar vortex”. After this mechanism is activated, a strong anticyclone is activated and keeps the cold at ground level. This anticyclone is not new, it is known as the Siberian anticyclone.
At the end, it appears that global warming is the main trend that has increased over the decades, but has not prevented the occurrence of cold epiphenomena. However, they remain less numerous than warm anomalies on a planetary scale, and this evolution should continue according to the climate scenarios presented by the IPCC.