Winter cold is crucial: it replenishes the snow blanket that supplies freshwater, regulates the life cycles of plants, animals, and insects, controls pests, and benefits crops. However, in the northern hemisphere, climate change is reducing the duration of winter. It is estimated that a third of the countries in the region have added at least one week per year with minimum temperatures above 0°C due to this phenomenon: Spain is one of them.
According to a study by Climate Central that analyzed 123 countries and 901 cities between 2014 and 2023, the team quantified the additional days with minimum temperatures above 0°C during December, January, and February —referred to as “lost winter days”— and compared them to estimates in a world without climate change, using the Climate Change Index (a tool that combines historical data with models).
Northern Hemisphere
Denmark, Estonia, Latvia, and Lithuania have had at least three weeks less of winter
“Our analysis shows that climate change is causing significantly warmer winters in the Northern Hemisphere, with more than 44 countries experiencing at least an additional week of days above freezing in the last decade due to human-caused warming,” says Kristina Dahl, Vice President of Science at Climate Central.
At a global level, Europe has recorded higher losses of winter days compared to other regions. Countries such as Denmark, Estonia, Latvia, and Lithuania have lost at least three weeks per year of winter temperatures below 0°C over the last decade.
When it comes to cities, Fuji (Japan) tops the list. On average, it experiences 64 days with temperatures above 0°C each winter, 35 of which are attributed to climate change. Cities like Khujand (Tajikistan), Turin and Verona (Italy), Bergen (Norway), and Riga (Latvia) have lost more than 30 days of winter each year.
“To prevent winters from getting even warmer, it is essential to urgently phase out fossil fuels such as oil, coal, and gas, which are the main drivers of global temperature rise,” Dahl adds.
44 countries have at least one week remaining
The broken down figures
25 countries in Europe and Asia have lost between one and two weeks of winter days due to anthropogenic climate change. European examples include Italy, France, Austria, Spain, and Norway. In Asia: Afghanistan, Iran, and Japan.
19 countries, mainly European, have lost at least two weeks per year. Some, like Denmark, Estonia, Latvia, and Lithuania, have experienced losses of over three weeks.
In addition, 35 cities in Europe and Asia have lost, on average, more than three weeks of winter days annually.
Spain
62% of the provinces reduced, at minimum, one week of winter
In Spain, the analysis shows that the territory has lost an average of 8 winter days each year over the last decade, and at least 62% of the provinces (32 out of 52) have recorded at least one week fewer of cold days each year.
The most affected province has been León, which now experiences 60 days with minimum temperatures above 0°C each winter, 17 of which are attributable to climate change. In contrast, Santa Cruz de Tenerife, Melilla, Las Palmas, Ceuta, and the Balearic Islands have not reported losses attributable to climate change, as their winters were already warm to begin with.
In Catalonia, Lleida has been the province that has lost the most winter days (11 days), followed by Barcelona (9), Girona (8), and finally, Tarragona (5).
A note on the results
The case of Catalonia
This analysis focuses on the warm days attributed to climate change, not on the total observed.
If we take the case of Catalonia, it is found that, in reality, Tarragona is the city that has had the most “warm” days during the winter (an average of 83 annually in the last decade), but Lleida is the one that has added the most “warm” days, although it is not the one with the most in absolute terms (a total of 50 annually have been observed).
The study also included twelve Spanish cities: the city that has lost the most winter days is Granada (14), followed by Pamplona (9) and Zaragoza (7). In Catalonia, only Barcelona has been analyzed, which has lost one day.
Change in patterns
We are having fewer frosty nights, and moreover, they are distributed differently
Emma Gaitán, PhD in Environment and head of the Meteorology and Climatology department at the Climate Research Foundation, points out that minimum temperatures in Spain have increased by up to 1°C in some areas, and it is expected that they will rise by 2 to 3°C by the end of the century.
This increase is reducing frost occurrences and modifying their distribution, as well as exacerbating extremes. “Record lows will occur less often, but with greater intensity. The patterns are changing,” adds the researcher.
Minimum records will occur less frequently, but with greater intensity”
Although the effects of the lack of cold weather may not be so evident, they have a profound impact on ecosystems, especially in agriculture. Javier Rodrigo, a researcher at CITA in Aragón, points out that winter dormancy is essential for fruit trees to be able to bloom and fruit normally.
Without enough cold, crops such as cherry, peach, or apple trees see their production affected, something that is already happening in areas of the Mediterranean coast such as Murcia or Valencia. Solutions are complicated: varieties that require less cold can be introduced, although this process is slow and depends on the market, or planting in higher areas, with the risk of spring frosts.
“We make projections for the future, and the situation is pessimistic,” Rodrigo confesses. They have considered various scenarios, and in the most likely ones, the winter cold will continue to decrease, especially in the Mediterranean basin."
In Murcia, some warm areas could become unsuitable for fruit cultivation. “I don't know if it will be in a decade or in five, but it is already happening: farmers are pulling out fruit trees without a viable alternative,” the researcher points out. In other less extreme cases, it is expected that a change in varieties or species will be sufficient.