The world is witnessing an increasing frequency of extreme floods—a phenomenon closely tied to rising global temperatures. Climate change’s fingerprints are evident in the deluge hitting Europe and regions worldwide, from the Brazilian highlands to the UAE’s deserts.
In this year alone, the world has witnessed a significant number of major flood events, resulting in substantial loss of life and property. According to the World Health Organization (WHO), floods are among the most frequent natural disasters, with drowning accounting for 75% of deaths in flood disasters. While comprehensive global data for the entire year is still being compiled, preliminary reports indicate that floods have caused thousands of fatalities worldwide.
For instance, in Spain alone, devastating floods in late October claimed over 200 lives, marking one of the deadliest flood events in Europe in recent history. In Nepal, heavy rainfall in September led to floods and landslides, resulting in 193 deaths and leaving 31 individuals missing. Similarly, Afghanistan experienced catastrophic floods earlier in the year, with reports indicating over 300 fatalities. The United Arab Emirates and Oman experienced their highest rainfall on record, while in East Africa, Kenya’s deadly floods led to landslides and disrupted thousands of lives. In Brazil, floodwaters engulfed an area the size of the United Kingdom, displacing over half a million people. The climate crisis is amplifying the frequency and severity of such events across the globe.
Climate Science Behind Extreme Flooding
Modeling precipitation and flood risk is a complex process, but one scientific principle is evident: warmer air holds more moisture. As global temperatures rise, more water vapor accumulates in the atmosphere, leading to heavier and more intense rainfall. Studies reveal that for every 1-degree Celsius (1.8 degrees Fahrenheit) increase in global temperatures, air can hold 7% more moisture. Since the pre-industrial era, global temperatures have risen by approximately 1.3 degrees Celsius, making extreme rain events more likely and intense.
Additionally, higher temperatures cause precipitation to increasingly fall as rain rather than snow, particularly in high-altitude areas. This accelerates runoff, making regions vulnerable to floods and landslides. A study in Nature (2022) found that rainfall extremes in high-altitude areas of the Northern Hemisphere increased by an average of 15% for every 1-degree Celsius rise in temperature. As temperatures continue to climb, the impacts on global flooding become more evident and severe.
The Global Shift in Rainfall Patterns
According to the UN’s Intergovernmental Panel on Climate Change (IPCC), a 1.5-degree Celsius rise in global temperatures — a threshold we are approaching — could see extreme rainfall events that would have been considered once-in-a-decade occurrences happening approximately 1.5 times per decade, with each event expected to be over 10% wetter. This change is evident in Europe, which experienced 7% more rainfall than average last year, leading to catastrophic floods across Italy, Norway, Sweden, and Slovenia.
Emerging research in attribution science, which links climate change to extreme weather events, now allows scientists to trace specific rainfall events back to global warming. For example, research from the World Weather Attribution project found that the devastating 2021 floods in Germany, Belgium, and the Netherlands were 1.2 to 9 times more likely to occur and had 3% to 19% higher rainfall due to climate change. Brazil’s floods in 2023 are estimated to have been made twice as likely by human-caused climate factors, with rainfall levels 9% higher than they would have been without global warming.
Floods’ Global Reach: Disparities in Impact
Floods are among the most destructive natural disasters, claiming lives, destroying infrastructure, and incurring massive economic losses. The number of people at risk of severe flooding has surged by 24% since 2000, with about 1.8 billion people — almost a quarter of the world’s population — currently living in areas exposed to “one-in-100-year” floods. Europe’s flood risk is particularly high, with Germany, France, and the Netherlands experiencing the highest exposure.
However, flood impacts are far from evenly distributed. Approximately 89% of people at risk of severe flooding reside in low- and middle-income countries, where rapid urbanization has placed more people in flood-prone areas. South and East Asia alone account for 395 million people at risk in China and 390 million in India. A study from Nature Communications in 2021 found that the population living in high flood-risk areas rose by 122% between 1985 and 2015, primarily due to urban expansion in vulnerable regions.
Will Flooding Worsen in the Future?
Without significant mitigation efforts to curb global warming, the risk of extreme flooding will only rise. The IPCC projects that a 2-degree Celsius increase in global temperatures would make once-in-a-decade rainfall events occur 1.7 times per decade, with each event delivering 14% more precipitation. Should temperatures rise by 4 degrees Celsius, these extreme rainfalls could happen nearly three times per decade, releasing up to 30% more rain.
In Europe, modeling from the European Commission’s Joint Research Center suggests that if no climate adaptation measures are taken and temperatures increase by 3 degrees Celsius, annual flood damages could soar to €48 billion by the end of the century. This could also lead to a threefold increase in the number of Europeans exposed to flooding risks. Countries worldwide face a similar fate, with increased flood risk translating into billions in infrastructure damage, economic losses, and a humanitarian crisis of displaced populations.
As rising temperatures drive more frequent disasters; only decisive adaptation and emission-reduction efforts can curb the escalating cycle of destruction and protect vulnerable communities.
