Will negative temperatures become a distant memory? Climate disruption, “due mainly to the burning of oil and coal”, is causing a significant increase in the number of winter days with minimum temperatures above zero, notes a new report from Climate Centralan independent group of scientists and climate communication specialists, published this Tuesday, December 17.
The study was conducted in 123 countries, between 2014 and 2023, and focuses on the months of December to February. According to the results, more than a third of the states observed experienced at least one additional week where the thermometer was positive due to global warming, caused by human activities. And Europe is the continent most impacted, since it is the one where “warming is twice as fast as the global average since the 1980s”, recalls the report.
According to data compiled for this analysis, Denmark, Estonia, Latvia and Lithuania have experienced as many as three additional weeks of temperatures above zero degrees over the past decade due to climate change. Denmark, for example, last winter counted 71 days of positive temperatures between December and February, twenty-one of which were directly due to a warming planet. The situation is just as striking in Lithuania: there would only be nine days above zero degrees without climate change during the three coldest months of the year; but the country counted 32 last winter.
France loses 21 days to negative temperatures
A total of 19 countries, mainly European, are beyond two more weeks of temperatures above zero degrees during winter, including Germany and Poland. France, like Spain and Italy, is between one and two weeks. France experiences 71 days above this threshold over the three winter months, including 21 due to global warming. In detail, there are regional disparities. The Grand Est had 62 days above zero last winter, including fourteen more due to the overall increase in temperatures, while Corsica only suffered two fewer days at negative temperatures.
On average over the last decade, around 44% of the cities analyzed (393 out of 901) have lost at least seven days of winter per year due to human activities. This is particularly the case for Paris, which lost up to twelve days of negative temperatures last winter, like Lyon, Chicago (United States) and Juarez (Mexico).
Beyond the observation made by the scientific group, the study also aims to warn of the consequences that these warmer winters would have in different areas. If snow forms when temperatures are at or below freezing, more days above that threshold could mean less snow accumulation. “Climate models suggest that snow cover in the Northern Hemisphere will decrease at a rate of -8% for 1°C of global warming of surface air,” the document points out. However, negative temperatures make it possible to replenish the snow cover which provides fresh water, which could lead to supply problems.
“Winter cold also plays a critical role in the life cycles of plants, animals and insects, influencing ecosystems throughout the rest of the year,” the report continues. Warmer, shorter winters can also disrupt the cooling of fruits and nuts, on which crops depend. Also, allergy sufferers beware: warmer, shorter winters mean earlier spring thaws and later fall – giving plants more time to grow and release allergenic pollen earlier in the spring and later in the autumn.
Impacts on nature and the economy
The scientific group also mentions the economic consequences of such a rise in temperatures in winter. The reduction in snow cover would put a stop to winter sports. Kristina Dahl, vice-president of Climate Centralrecalls that “mountain tourism in winter in France is estimated at 10 billion euros, or 15% of national tourism turnover”.
And in the world? The winter sports industry was valued at approximately $12.5 billion in 2023. Note that temperatures in the 19 cities that have hosted the Winter Olympics since 1950 have warmed by 2.7°C in average, since 1950. In the 2080s, under a high emissions scenario, almost all host cities of previous Winter Olympics would be “unable to provide reliable services of safe and fair conditions” for outdoor snow sports.