A study published this week claims that the heat wave that hit southeastern Europe and Bulgaria was exacerbated by human-driven climate changes.
Image: Wildfire in the suburbs of Rome, Italy. Source: Davide Faranda
The high temperatures that hit Europe in the last few weeks caused human deaths, fuelled wildfires, forced airport closures, strained power grids and helped spread a locust plague across Europe were made up to 3ºC hotter due to climate change.
ClimaMeter found that heatwaves akin to those that hit Eastern and Mediterranean Europe are up to +3°C more intense than the previous heatwaves recorded in the region, with temperature anomalies reaching +7 °C. ClimaMeter scientists have determined that human-driven climate changes made these temperatures even higher.
The unusually hot weather threatened human health and caused numerous fires. The extreme phenomenon was not the only one for this year – there was also a heat wave in the month of June, which beat the temperature records in our country since at least 1930, as well as in the world for the last 144 years. July 21 marked the warmest day globally since meteorological records began, and just one day later, on July 22, the record was broken, with the Earth’s average temperature of 17.15 °C. If the Earth warms by 3°C, the number of deaths from heat stress will triple compared to an excess of 1.5°C.
It is known that extreme weather events are increasing as a result of climate change, and that heat waves will occur more frequently and will be increasingly intense and long-lasting. And we recently witnessed such a phenomenon.
South-East Europe heatwave was up to 3°C warmer due to human influence, study finds
Earlier this month, Southeast Europe experienced a prolonged heat wave, peaking between July 17 and 19. Temperatures in the Balkan Peninsula were by up to 7°C higher than normal and there was almost no precipitation during this period. The heat wave was up to 3°C warmer due to human influence . These are the leading conclusions drawn from an attributive study published on July 25 on the scientific platform ClimaMeter, which aims to determine the human role for individual extreme phenomena. The conclusion was drawn by looking at similar weather events for the area and comparing events in the 21st century (2001-2023) with those that occurred at the end of the 20th century (1979-2001). One of the important conclusions of the study is that this type of heat waves will happen more and more often in June, and before that their occurrence was relatively rare . Another important conclusion is that the phenomenon is not atypical, but human-driven climate change has played a key role in the higher temperatures, while the role of natural climate fluctuations has been minimal.
Figure 1: Results of the ClimaMeter analysis of the July 2024 heat wave, for the days 17 to 19 July 2024. Left – How much this heat wave was caused by human-driven climate change. Right – how many similar events have occurred in the past.
The heat wave over the Eastern Mediterranean in June, which also affected Bulgaria, was also 1.5 °C warmer due to human-induced climate change, according to another analysis by the scientific organization ClimaMeter, published on July 18, 2024. They studied the heat wave that occurred between June 11 and 14 of this year. and have compared it with other heat waves previously observed in this part of the world.
The data have already been published and we know that in Bulgaria the month of June was the warmest since at least 1930, surpassing the previous record from June 2012. The complete data for the summer of this year will be available only after the month of August. So far, the hottest summer in Bulgaria was in 2012, followed by 2007, 2023 and 2017.
The unusually hot weather in July had a very negative impact, with thousands of hectares of land burning in North Macedonia, Albania, Greece and Bulgaria.
In our country, the heat wave started after July 5, and it was warmest on July 17 and 18, when the National Institute of Meteorology and Hydrology (NIMH) declared a red code for very dangerous weather.
Temperature records were recorded in some climate stations, such as in Ruse and Sandanski, when temperatures of 41 °C were measured on July 17 , and in Varna the maximum temperature reached 36°C. In Sandanski, the maximum temperature was above 40°C for 9 days. During the heat wave, there were hundreds of fires in the country. In the vicinity of Varna, the fires forced the temporary closure of the “Hemus” highway on July 15. The village of Voden in Yambolsko was seriously affected, as the flames affected 35 houses, of which 15 were completely burnt. And in the village of Otets Paisievo in Plovdiv, the fire burned 30 houses. There were also large fires in Starozagorsko (Fig. 3).
Figure 2. Satellite photo from July 18 of burning areas in the region of Starozagorsko. Source: Copernicus .
Although most fires are human-caused, climate change is making the conditions for them worse – the times of year during which fires can occur are lengthening, and hotter, drier weather favors burning larger areas for longer.
The exact estimate of human casualties from this heat wave is difficult at this stage, but it is known that heat waves are the most dangerous extreme phenomenon that significantly aggravates the health condition of people, and the representatives of vulnerable groups such as the unemployed, poor etc. The assessment also indicates that Bulgaria will be affected by heat waves more and more frequently and strongly.
In the Eastern Europe region, there were also a number of consequences of the July heat wave
In Hungary, the second largest airport in the city of Debrecen had to temporarily close due to “thermal stress” on its runways. The CEO of the Hungarian National Railway Company stated that the carriages, which are 40-50 years old, were not designed for the current climate. In Romania, hospitals experienced frequent power outages due to the strong need for cooling with air conditioners. In some areas of Greece, for 14 days the temperature exceeded 40°C, forcing the Acropolis to be closed for several hours. A “code red” was declared for 14 Italian cities because of the heat and humidity. In Sicily, work in agriculture and construction was banned between 12:30 and 16:00.
In addition to the past heat wave, this year has seen other cases of unusually warm weather in the Northern Hemisphere, such as that in Southeast Asia since late spring, in the United States since early July 2024.
On July 22, 2024, the warmest day worldwide since the beginning of meteorological measurements was recorded – 17.15 °C
The previous warmest day was on July 21, when the Earth’s average temperature was calculated to be 17.09 °C. And already in the last 13 months, the world has been more than 1.5°C warmer than the average since the end of the 19th century, putting the Paris Agreement’s safe limit of 1.5°C on warming into question.
Figure 3. Average daily global temperature in 2023 and 2024 compared to the average temperature for the periods 1940–2002 and 1991–2020.
Human-caused climate change is the main cause of the increase in the intensity and frequency of heat waves in 80% of the Earth’s regions in recent decades, according to the latest IPCC report. According to the panel, there has been an increasing trend in heat stress in Europe since 1973, and it will continue to increase in the future under all climate scenarios, especially in the southern regions of the continent. This will lead to a number of consequences, including health, economic, social and environmental.
Warming in Europe will continue to be faster than the global average, with a negative impact on southern regions, with increased cooling needs and losses to agriculture. If the Earth warms by 3°C, the number of deaths from heat stress will triple compared to 1.5°C, according to IPCC data.
What will the climate be like in Bulgarian cities in 60 years?
Recently, a new initiative started working – Fritzlab , which presents analytical results for major cities around the world, including Bulgaria. The analysis compares cities around the word, showing how the city climate will change in the future and what other modern city it will resemble. For example, In a high emissions scenario in Plovdiv, summers will be by 7.5°C hotter and 18% drier, and winters by 4.9°C warmer than now.
Figure 4. How will the climate of the city of Plovdiv change in 60 years? Source
In Sofia, the climate after 60 years is expected to be most similar to that of the city of Stip in North Macedonia, with a warming of the summer season by 7°C and a decrease in precipitation by 18%. Overall, under future warming, the climate of our cities is expected under most climate scenarios for the future to resemble the modern climate of cities in Northern Macedonia and Northern Greece – higher temperatures and less precipitation in summer. These changes will also have an impact on the vegetation – if today we have broad-leaved and mixed forests, then after such a warming it is likely that we will move to a greater presence of Mediterranean vegetation, which will certainly affect our agriculture as well.
The summer season by the sea will be extended, while the diminishing snow will greatly threaten our winter resorts. There will be many other impacts, most of which will be negative.
Climate change is becoming increasingly evident and their occurrence more frequent and more severe. The attribution analyses fully confirm this fact. In addition to mitigation measures, measures to adapt society to the changing environment will be critical – primarily to heat waves and fires, as well as to draughts in the summer season.
The article uses materials from:
https://www.facebook.com/PrognozataZaVremeto
https://www.climateka.bg/atributivni-prouchvaniya/
https://www.copernicus.eu/en/media/image-day-gallery/bulgarian-regions-battling-fires
https://www.svobodnaevropa.bg/a/pozhar-helikopteri/33038713.html
https://www.bbc.com/news/articles/crg7pen1xj7o
