The average annual air temperature in Croatia has been steadily increasing since the second half of the 20th century, confirming climate model predictions of an increase of 2-2,4 degrees by 2070, but responsible decisions can mitigate the most severe consequences of climate change, Croatian climatologists point out.
The warming is recorded in all seasons, but is most pronounced in summer, when the difference becomes most obvious. Also, the increase did not only affect average values, but also increased the minimum and maximum daily air temperatures.
In summer, we are increasingly recording warm and hot days, but also warm nights, when the temperature does not drop below 20 degrees Celsius, according to a report by Sara Ivasić from the Department of Climate Change and Biometeorology of the DHMZ, which was submitted to Hina.
For example, in continental Croatia during the 1990s there were almost no warm nights, while in the last ten years, which are also among the warmest on a global scale since measurements have been made, we have had up to ten of them every year.
In the areas along the Adriatic, the number is even higher. In Dubrovnik and Split, as many as 91 percent of nights in the three summer months of 2004 were classified as warm nights. Once rare, unusually warm summer days and nights have now become part of the climate reality.
Instead of 33, the usual 35 degrees Celsius
According to the moderate scenario of greenhouse gas emissions growth (RCP4.5), Croatia will experience significantly warmer summers in the period from 2041 to 2070 than we remember from the period from 1981 to 2010.
In areas along the Adriatic and in central and eastern Croatia, an increase in summer maximum temperatures of 2,0 to 2,2 degrees Celsius is expected, while the projected increase for mountainous Croatia and inland Istria is between 2,2 and 2,4 degrees Celsius.
"This means that in today's climate, a day with a maximum temperature of 33 degrees Celsius, which we experience as a hot summer day, would in the future be closer to 35 degrees Celsius, which would not be an exception, but a common occurrence," Sara Ivasić specifies.
Also, central Croatia could have 7,5 to 10 additional warm days each summer. Inland Dalmatia is expected to have 5 to 10 more warm days, and along the coast this increase would be from 10 to 17,5 days.
Nights will also become warmer. The number of warm nights could increase by around 22 percent in areas along the Adriatic and by 20 to 22 percent in central Croatia.
"The increase in the number of warm nights leads to a decrease in the possibility of nighttime refreshment and quality rest, which creates increasing heat stress, both for people and for nature," points out the DHMZ climatologist.
Warm days in climate projections are defined as days when the highest daily air temperature reaches or exceeds a threshold of 25 degrees Celsius. Warm nights are nights when the temperature does not drop below a certain thermal threshold.
We will have less rain in the summer.
Heat stress in cities is further affected by the urban heat island effect. The extremely uncomfortable summer heat is not only influenced by the weather, but also by the materials that predominate in urban areas, traffic and the operation of air conditioning. Surfaces such as concrete and asphalt effectively absorb solar radiation during the day and slowly release it back into the atmosphere at night. Vehicles in traffic emit greenhouse gases and heat, while air conditioning systems expel excess heat from indoor spaces onto the streets. As a result, cities can be up to 10 degrees Celsius warmer than surrounding rural areas, making nights even less comfortable and putting a strain on the health of city dwellers.
Climate projections show that the amount and seasonal distribution of precipitation will change in Croatia. We will have less rain in the summer almost everywhere, and the largest reduction, of 15 to 20 percent, is expected in the coastal region, central Dalmatia and mountainous Croatia.
Less precipitation during the summer means more dry days. Their number could increase especially in the mountains and interior of Dalmatia (up to 5 percent to 7,5 percent more dry days per year), and this trend will be most pronounced in the summer (from 5 percent to 7,5 percent additional dry days). Therefore, it is likely that we will experience an increasing number of drier summers, with longer periods without rain, it says.
Reducing emissions and investing in adaptation
The climate changes described will have a direct impact on our lives and economies. In agriculture, rising air temperatures can extend the growing season of plants and increase heat accumulation, but a lack of precipitation in summer could threaten yields of traditional crops. Also, rising soil temperatures and the duration of high soil temperatures further increase the evaporation process, which loses water from the soil.
Also, a further increase in the risk of forest fires is likely in Dalmatia, but also in the continental parts of the country.
All of this could reduce the appeal of the peak tourist season, so spring and autumn could become more attractive periods for vacations and outdoor activities.
"The changes predicted by climate models, warmer summers, more frequent warm nights, a lack of precipitation in the summer with more frequent droughts, are no longer scenarios of the distant future. This is a process that has already begun. Our society will need to adapt to new climate conditions, with the modernization of agriculture and the establishment of irrigation systems, more efficient management of water resources, and even the implementation of solutions to mitigate the effects of heat waves in cities," points out Sara Ivasić.
She emphasizes that the challenges are not small, but that timely action to reduce greenhouse gas emissions and invest in adaptation can mitigate the most severe consequences of climate change and enable the benefits to be sustainably exploited, such as extending the tourist season into spring and autumn.
Photo: HINA/Baldo Marunčić
