Study: the reduction in the number of frost days will have a negative impact on the ecosystem

Since the beginning of the 1960s, the average number of frost days in the Czech Republic has decreased by 4.7 per decade. While between 1961 and 1970 there were an average of 126.5 frost days per year, between 2011 and 2020 there were only 99.8. This decade saw the fastest decline, with 11 fewer frost days than the previous one.

Just as frost days are decreasing, so are icy days, when the temperature does not rise above freezing for an entire day. This decline is even more pronounced, says Pavel Zahradníček of the Czech Academy of Sciences’ Institute for Global Change Research:

“The drop in the number of icy days is even more significant. In the 1960s we saw about 47 days of ice per year, but in the last decade it was only 23 days. That’s a 50% drop and that’s a really significant change in the climate index.

Pavel Zahradníček says that current temperature trends and data are not surprising, as they are in line with 15-year forecasts. However, they are closer to pessimistic scenarios.




Photo: Štěpánka Budková, Radio Prague International

The estimates are based on the amount of carbon dioxide emissions into the atmosphere, with the pessimistic estimate assuming that emissions will not be regulated in the future, while the middle estimate is based on the assumption that emissions will be regulated but not strictly limited.

In the Czech Republic, temperatures have increased throughout the year, but in winter and summer the changes are more pronounced than in other seasons.

The decrease in the number of frost days can have a lasting impact not only on the country’s ecosystem, but also on the economy or the water supply, says Mr Zahradníček:

“Frost days are very important for the climate and the landscape of Central Europe. With the decrease in the number of frost days, we also see fewer days with snowfall and snow cover.

“And snow cover and snowfall are very important to saturate groundwater supplies. That’s one of the reasons that caused the droughts of 2015 or 2020.”

Warmer winters with fewer frost days also have a negative impact on vegetation and soil, Zahradníček says, especially on fruit growers in warmer parts of the country.
The early end of winter and the arrival of spring wake up the trees earlier, but the risk of April frosts remains the same.

While there is currently a 25% risk of frost damage to flowering trees in South Moravia, by the end of the century it could reach 60%, or once every two years.

Berta D. Wells