The article was written by Patryk Strzałkowski, a journalist at Gazeta.pl.
Seven people died, thousands had to leave their homes, and many cannot return. Damage assessments are ongoing, but the losses are already estimated in the billions. The consequences in the entire region are much greater. Now, scientists have answered the question of whether the September floods were linked to climate change.
A study conducted by an international team of scientists found that climate change was responsible for the intense rainfall in Poland and the region. The heavy downpours over Central Europe were caused by a system known as the Genoa low. The analysis showed that while such weather systems are neither more frequent nor rarer, the rain they bring is stronger and more likely due to the warmer climate we've created.
"Our study has demonstrated a link between climate change and the torrential rains that flooded Central Europe. These floods highlight the devastating consequences of warming caused by fossil fuels," said Dr. Joyce Kimutai, a researcher at the Grantham Institute for Climate Change and the Environment at Imperial College London. "As long as oil, gas, and coal are not replaced by renewable energy, storms like Boris will produce even heavier rainfall, leading to floods that will devastate economies," she emphasized.
Stronger Floods in Poland Due to Climate Change
The study found that such heavy rainfall is a rare event - so rare that it's difficult to find historical references to compare it. In less than four days, some areas saw 300-400 liters of water per square meter (compared to an annual average of around 600 liters per square meter). The heavy rains covered a wide area, from Slovenia through Austria and the Czech Republic to Poland, and were more intense than those that caused floods in 1997 and 2002.
The analysis showed that such heavy rainfall is at least twice as likely today. In the current climate, it's considered a "100-year rain," meaning it occurs once every hundred years on average. Statistically, this means there is a 1 in 100 chance of it happening in any given year (without climate change, that probability would be 1 in 200). This is evident from the fact that similarly extreme rainfall occurred less than 30 years ago, in 1997. However, in today's warmer climate, the 1997 flood would have been even worse.
"Climate is telling us that the flood will come sooner or later. And climate change is making that flood more likely to come sooner rather than later," said Prof. Bogdan Chojnicki from the Poznan University of Life Sciences, one of the study's authors.
The study also found that the rains are not only more frequent but also more intense. The rainfall that caused this flood was at least 7%, and possibly as much as 20%, stronger than it would have been in a world without climate change. While 7% may seem like a small increase, it's important to remember that our infrastructure was built for a past climate and may not withstand the more frequent and intense extremes.
If we heat the Earth by a total of 2 degrees Celsius, which could happen by mid-century, the intensity and likelihood of such rainfall will increase further (the current level of climate warming is about 1.3 degrees). At that point, rainfall could become an additional 4% stronger and 50% more likely.
The authors of the analysis also warn that this increase may be underestimated, and the actual impact of climate change on extreme rainfall in the future could be greater.
Modern Study
This is the first such analysis focused on Poland. It was conducted by scientists from the international team World Weather Attribution, which uses state-of-the-art research methods to assess the impact of climate change on specific weather events. A total of 24 researchers participated in the study.
Costs of Climate Change
Damage assessments are ongoing, and in some towns, cleanup efforts will take time, let alone reconstruction. According to the latest government estimates, the damage to water infrastructure amounts to 3.5 billion PLN, and the damage to centrally managed roads and bridges is 1.5 billion PLN. Local roads may require another 1.5 billion PLN for repairs.
The floods demonstrate the high costs of climate change. Even with several days to prepare, the floods devastated towns, destroying thousands of homes.
