“Climate change and other human factors have exacerbated the flood disasters in Libya and Greece. Anthropogenic warming has made heavy rainfall up to 10 times more likely in Greece, Bulgaria and Turkey and up to 50 times more likely in Libyawhile factors such as construction in high flood plains, poor dam maintenance and other local factors contributed to the rainfall turning extreme weather into a humanitarian disaster.”

This is highlighted by a study conducted by 13 researchers as members of the World Weather Attribution team, including scientists from universities and research centers in Greece, the Netherlands, the United Kingdom and the United States.

The heavy rains that wreaked havoc in large parts of the Mediterranean in early Septemberare more likely to occur due to climate change resulting from greenhouse gas emissions, according to a rapid analysis by an international team of climate scientists from the World Weather Attribution Group.

The study also found that the devastation caused by the heavy rainfall was much greater due to factors including construction in flood-prone areas, deforestation and the effects of the conflict in Libya.

For the history of the meteorological situation, it is stated that at the beginning of September, a detached low that affected Spain and a low pressure system named Daniel, which formed in the Eastern Mediterranean; caused heavy rainfall over a period of 10 days in many countries, including Spain, Greece, Bulgaria, Turkey and Libya.

To quantify the effect of climate change on the region’s rainfall, the scientists analyzed climate data and climate model simulations to compare past climate with today’s climate reality, after from an increase of about 1.2°C degrees in the average temperature of the planet compared to that which prevailed at the end of the 19th century. The methodology followed for the analysis has been evaluated and published in scientific journals.

The scientists divided their analysis into three areas:

• Libya, where the analysis focused on the north-eastern part of the country, where most of the rainfall fell,

• Greece, Bulgaria and Turkey, where the analysis looked at maximum rainfall over four consecutive days and

• Spain, where most of the rain fell in just a few hours.

For Libya, scientists found that human-induced climate change made the phenomenon up to 50 times more likely to occur, and caused up to 50% more rainfall during this period, as a result of anthropogenic greenhouse gas emissions. The phenomenon is still extremely unusual and can only be expected to occur once every 300-600 years, in today’s climate.

For Greece, Bulgaria and Turkey as a whole, the analysis showed that climate change made the phenomenon up to 10 times more likely to occur, and caused up to 40% more rain, as a result of human activities that have warmed the planet. For this large area, which includes parts of the three countries, the event is now quite common and can be expected about once every 10 years, meaning it has a 10% chance of happening every year.

Specifically, however, for central Greece, where the heaviest rainfall occurred and the most disasters occurred, the phenomenon is less likely and is expected to occur only once every 80-100 years, which equates to a 1-1.25% chance of occurring each year.

In Spain, where most of the rain fell in just a few hours, scientists estimated that such heavy rainfall is expected once every 40 years, but they were unable to perform a full analysis as available climate models do not properly capture heavy rainfall on time scales shorter than a day.

It is noted that the above findings have large mathematical uncertainties, as the phenomena occurred in relatively small areas and most climate models do not represent rainfall well at these small spatial scales. Although scientists cannot completely rule out the possibility that climate change has not affected the likelihood and intensity of the phenomena, they are certain that it has played a role for three main reasons:

• Increased temperatures generally lead to heavier precipitation, and studies predict heavier precipitation in the region of increasing temperature.

• No evidence was found for factors that may make heavy rainfall less likely and offset the effect of climate change.

• Data from weather stations in the area show a trend towards heavier rainfall.

Due to the constraints imposed by climate models, scientists have not given a central estimate of the impact of climate change, as they did in previous studies, but gave an upper limit of this effect. A key finding of the study is that the very large impacts observed in some of the regions were caused by a combination of high population vulnerability and exposure to the event. For example in the affected area in Central Greece, most cities and communities and much of the infrastructure are located in areas with high flood risk. In Libya, a combination of several factors, including long-term armed conflict, political instability, potential design flaws and poor maintenance of dams contributed to the disaster. The interplay of these factors, and heavy rainfall exacerbated by climate change, created the extreme disaster.

“The extreme amounts of rainfall that hit central Greece and their devastating effects are a pivotal point in the direction of the need to redesign early warning systems to be impact-orientedthe response capacity of the Civil Protection and the infrastructures to be more resistant in the era of climate change”, said the Director of Research at the National Observatory of Athens, Vasiliki Kotroni.

In the Mediterranean, which is a “hotspot” “of the risks fueled by climate change”, said the Lecturer in Climate Science at the Grantham Institute – Climate Change and the Environment, Imperial College London Friederike Otto, . “The Mediterranean is a hotspot of risks fueled by climate change. After a summer of devastating heatwaves and wildfires with the very clear imprint of climate change, quantifying the contribution of global warming to these floods has proven more difficult. But there is absolutely no doubt that reducing vulnerability and increasing resilience to all types of extreme weather conditions is paramount to saving lives in the future,” he said.

Julie Arrighi, director of the Red Cross/Red Crescent Climate Centre, said: “This devastating disaster shows how extreme weather events caused by climate change are combining with human factors to create even greater impacts, as more people, assets and infrastructure are exposed and vulnerable to flood risks. However, there are practical solutions that can help us prevent these disasters from becoming the norm, such as enhanced emergency management, improved forecasting and impact-based early warning systems, and infrastructure planning for the future climate.”