Samsun University Özdemir Bayraktar Faculty of Aviation and Astronautics, Head of Climate Science and Meteorology Engineering Department, Assoc. Dr. In the research conducted by Hakan Aksu, it was calculated that summer in Türkiye started 2.1 days earlier on average in 10 years, autumn became shorter and spring became longer.
Research on changes in the start and end dates of seasons focuses on the effects of climate change on the duration of seasons and temperature averages.
In this context, in the research titled "Determination of seasonal shifts across Türkiye in the period 1965-2020", temperature data of 65 meteorological observation stations were examined.
In the research, it was calculated that the summer season in Türkiye starts an average of 2.1 days earlier in 10 years.
Considering the average duration, the region where the beginning of summer is most prominent was the Aegean Region with approximately 2.4 to 2.9 days in 10 years, followed by Marmara with 1.4 to 3.2 days, the Mediterranean with 1.4 to 2.8 days, the Black Sea with 1.2 to 3.2 days and Central Anatolia with 0.3 to 2.8 days. It was recorded as approximately 1 to 1.5 days per 10 years in Eastern and Southeastern Anatolia, which will be lower than other regions.
According to the research, the spring season has lengthened in all regions except Southeastern Anatolia. The most significant extension was seen in the Marmara and Western Black Sea regions, with 1.5 to 3.5 days in 10 years. No change was detected in Southeastern Anatolia.
While it was determined that the autumn season was shortened by an average of 2 to 3 days in 10 years in the Black Sea, Marmara and Aegean regions, no change in autumn length was observed in Southeastern Anatolia.
It was observed that the beginning of winter shifted 1-2 days earlier in 10 years, especially in Southeastern Anatolia, but no change was observed in other regions.
"CHANGE IN THERMAL CHARACTERISTICS OF THE AUTUMN SEASON IS IMPORTANT"
Answering the questions of the AA correspondent, Aksu said that increasing temperatures due to climate change not only increase heat waves, but also cause the atmosphere to retain more moisture and cause extreme weather events that trigger each other, such as sudden, heavy rains and floods, to occur more frequently.
Stating that seasons in the astronomical calendar are fixed periods of 90 days, a dynamic approach that takes temperature and weather conditions into account is needed to define real seasons, Aksu continued as follows:
"Rising temperatures cause the winter seasons to become shorter and milder, while also lengthening the calendar duration of the summer seasons and increasing their thermal intensity. This shifts the start and end dates in transition seasons such as spring and autumn, which can cause the seasons to lengthen. It affects the balance of seasonal continuity."
Stating that autumn is extremely important in slowing down the effects of climate change and contributing to balancing the global climate, thanks to the high heat capacity of the seas, Aksu said, "For a country surrounded by seas on three sides, the change in the thermal characteristics of the autumn season becomes important. The sea remains warm, and cold and hot weather continues to come on top of it through certain systems." he said.
"RECORD TEMPERATURES AND EXCESSIVE RAINFALLS ARE CONCRETE INDICATORS OF CLIMATE CHANGE"
Emphasizing that the increase in autumn temperatures, the increase in sea surface temperatures and the accumulation of atmospheric moisture may increase the risk of heavy convective precipitation and sudden floods, especially in transition seasons, Aksu stated that transition seasons may become more risky in this respect.
Pointing out that there are significant differences in the thermal and calendar duration and characteristics of all seasons, Aksu said, "When the thermal characteristics of the seasons are examined, the summer period, which is the hottest 90-day period of the year, stands out as the season in which the temperature increase will be highest, with an average increase of 0.2 to 0.7 degrees Celsius every 10 years." he said.
Sharing his determination that the effects of climate change can no longer be ignored, Aksu continued as follows:
"The current picture reveals that climate change is no longer a future projection in Türkiye, but has turned into a concrete and increasing reality, manifested by both historical records broken in the thermal regime and excessive emissions in the hydrological cycle, that is, the shift of precipitation towards very extreme precipitation." he said.
"THE END OF DEFOLIATION AND VEGETATION PERIOD IS BEING DELAYED"
Explaining that seasonal shifts will have socioeconomic consequences in areas such as agriculture, energy, water resources, disaster management and tourism, Aksu stated that climate adaptation strategies should be implemented with an interdisciplinary approach.
Assoc. Dr. Aksu underlined that the temperatures during the period when plants grow and develop throughout Türkiye have increased significantly and made the following evaluations:
"This increase causes phenological stages such as leafing and flowering in plants and trees to move forward in the spring, shortening the maturation period, increasing the risk of later frosts in plants that wake up early, and increasing the risk of some pests. In autumn, leaf fall and the end of the vegetation period are delayed due to high temperatures. In addition, the increase in temperature accumulation increases heat stress on plants in the southern regions. Some cultivated plants that did not grow before in the high altitude areas of Central and Eastern Anatolia. "It can lead to the formation of climate zones that allow agriculture."
Aksu commented that if seasonal shifts continue at this rate, there will be significant changes in terms of timing and temperature in all seasons in the next 20 to 30 years, and that the world is at a critical breaking point.
