To the bones and the coldness reaching to the core has caused the residents of southern Finland to put on one layer on top of another this week.
It was 16 degrees below zero in Helsinki on Thursday evening. According to the Finnish Meteorological Institute, the wind made the frost bite as low as -25 degrees. The scarf had to be pulled towards the nose in order to keep the feeling in the cheeks.
According to the forecast, the same trend will continue on Friday morning as well.
Hytinävikko has resurrected an old, confusing question about weather and climate: wasn't the climate supposed to warm up?
“I get messages on social media asking why it's not a black Christmas and why it's freezing and that climate change doesn't exist,” says Yle's meteorologist and nonfiction writer Kerttu Kotakorpi.
“So this is probably a very topical topic again.”
Subject is also relevant in terms of people's wallets, because the severe cold increases the price of electricity. On Friday, stock exchange electricity is record expensive. In the evening, electricity costs 2.35 euros per kilowatt hour including VAT.
The frosts have raised electricity consumption to almost record levels, and on Thursday the grid company Fingrid urged Finns to avoid electricity consumption.
Periods of severe frost also increase district heating costs and cause headaches for electric car drivers.
HS asked Kotakorve and two researchers from the Finnish Meteorological Institute, whether freezing weeks like the one experienced in southern Finland will become rarer as the climate warms.
The short answer is yes.
The long answer is so long that it cannot be summed up in one sentence other than by stating that chilling surprises can also be expected when the climate changes.
First it must be said that such weeks have already become rare.
Why wouldn't they be: Finland is warming twice as fast as the world average, when the greenhouse gas emissions emitted by mankind heat up the planet. Early winters warm up especially quickly.
“If you think about global warming as a phenomenon, it specifically means that the climate is warming. [Hallitusten välisen ilmastopaneeli] The IPCC's main messages also state that extreme heat is increasing and extreme cold is decreasing,” says a researcher at the Finnish Meteorological Institute Mika Rantanen.
“Such extreme colds, if this can even be counted as such, are becoming rarer.”
A senior researcher at the Finnish Meteorological Institute says the same Joonas Merikanto.
“Climate change increases the warm periods of summer and reduces the cold frosty periods of winter. That's the basic trend and the best answer to this.”
In Kaisaniemi the curve of the coldest days of winter jumps a lot for the measuring point that has faithfully produced data since the 1840s. Finnish winters are characterized by great variation. The trend towards warmer temperatures can still be seen.
Rantanen advises to look at the curve especially from the 1970s onwards. Prior to that, local warming in Kaisaniemi could also have been caused by the densification of the urban structure.
Kerttu Kotakorpi calculates that in the 2000s there have already been 11 winters when Helsinki has never experienced a frost below -20 degrees.
Rantanen takes an example further north: In the 20th century, -40 degrees was observed in Sodankylä every other winter, but in the 2000s, that reading was measured only once.
“It seems that especially in these coldest weathers, people's memory is quite short,” says Kotakorpi. “When we go to 15 degrees below zero, it feels really cold anyway.”
When your nose freezes, you don't have to wonder if the coldest winter of your childhood was even colder.
Take a look it is also worth raising above Kaisaniemi and Finland. In Finland, it is now easy to get a completely wrong idea of the global situation this winter, researcher Rantanen says.
“In recent months, Finland and Fennoscandia have been pretty much the only place in the world where it is colder than usual,” says Rantanen.
Rantanen shared the October and November temperature deviation in the photo messaging service X. Finland, Sweden and Norway are the blue cold spot in the otherwise red northern hemisphere. Almost everywhere else has been warmer than the average for the time.
October and November were the warmest in the history of measurements in the world, and December and the whole year 2023 are also reaching the same record.
Still, there will be times in the future when Finland is a global exception.
That leads to the long answer, which includes both the so-called polar vortex and the more familiar Gulf Stream.
Kotakorpi and Rantanen raise the polar vortex and the Gulf Stream as surprising factors that, by affecting them, climate change can in some situations even increase the possibility of cold extremes in Finland.
They may have an effect in the opposite direction to general warming.
Polar vortex means the winds of the upper atmosphere, which enclose the fiercely cold air masses of the arctic winters. When the polar vortex breaks up from time to time, arctic air “drains” somewhere in more southerly latitudes.
There are recent studies that climate change could increase polar vortex breakdowns. An explanatory mechanism would be a narrowing of the temperature difference between the polar region and its southern side.
The temperature difference is narrowing because the areas near the North Pole are warming faster than the rest of the Earth.
According to Merikanno, it is mainly due to two things. First, the continents are warming faster than the oceans. Secondly, the issue is affected by the melting of the northern sea ice, which strengthens the warming as the dark sea binds the heat.
“The warming of the polar region can make the breakup of the polar vortex more likely,” says Merikanto.
“There are a couple of very good publications about it, but no consensus yet [tieteellistä yksimielisyyttä] however.”
Second the surprise factor, the Gulf Stream, is the warm sea current of the Atlantic Ocean. Thanks to that, the Nordic countries are much warmer than the extreme northern location would otherwise allow. The Gulf Stream threatens to be disrupted as climate change progresses.
Kotakorpi describes the Atlantic sea currents as a “conveyor belt”: from the equatorial region, warm water flows near the surface to the north, and from there, cold water flows deeper towards the south.
“The temperature difference has been its engine,” says Kotakorpi. And now that gap is narrowing.
In addition, the ocean's conveyor belt can be slowed down by the melting of Greenland's glaciers, as fresh meltwater does not sink to the bottom like salty seawater.
According to Merikanno, there are theories according to which the Atlantic ocean currents could also slow down suddenly, in which case they would be one of the so-called tipping points of climate change.
“Probably, however, the slowdown of Golfvirta will not dominate [Suomen ilmaston kehitystä]”, says Merikanto.
Kotakorpi reminds that the effects of climate change are generally not as straightforward as one might think. This also applies to financial consequences.
One example is snow. In northern Finland, the amount of snow may increase as precipitation increases, and there may be surprises in the south as well.
“Although [Etelä-Suomessa] the snow season will decrease, plowing equipment may be needed even more than before, when there may be so much snow at once,” says Kotakorpi.
This is influenced by the “snow cannon effect” of the Baltic Sea, which remains melted, i.e. its water vapor turning into snowfall under suitable conditions.
Hardly The calculable consequences of climate change also include cloudiness and winds.
According to some studies, winters may become cloudier as a result of warming. Warm air can contain more moisture than cold air.
The cloud cover evens out the extremes, and further reduces cold spikes.
“The cloud roof prevents the heat from escaping into space,” says Rantanen.
However, according to Merikanno, nothing certain should be said about the increase in cloudiness yet. “There is not enough material, and the models point in both directions,” he states.
There is typically a lull during the worst frosts in Finland, but this week seems to be an exception to that rule. On Wednesday, Finnish wind turbines produced electricity at more than a quarter of its maximum capacity.
Changes in windiness are difficult to model, but the current information is that the wind conditions in Finland will not necessarily change much in the coming decades.
“You hear a lot that windiness has increased, but there is no research on that,” says Kotakorpi.
“We probably won't see any big change in the wind,” Merikanto confirms.
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