Despite being amongst the world’s most destructive extreme weather events, tropical cyclones are relatively rare. In a given year, only around 80-100 tropical cyclones form globally, most of which never make landfall. In addition, accurate global historical records are scarce and only span the last 30-100 years. This lack of data makes tropical cyclone modelling challenging and complicates local-scale risk assessments.
To overcome this limitation, an international group of scientists led by Nadia Bloemendaal from the Institute for Environmental Studies, Vrije Universiteit Amsterdam, has used a novel methodology where historical data are combined with global climate models to generate thousands of “synthetic tropical cyclones”.
By creating a large dataset with these computer-generated cyclones, which have similar features to natural cyclones, the researchers were able to project the occurrence and behaviour of tropical cyclones over the next decades in the face of climate change, even in regions where tropical cyclones hardly ever occur today. The results were obtained at a global scale and with a very high resolution of just 10 kilometres.
Sanne Muis (Deltares, co-author): “With a statistical model, in combination with data from high-resolution climate models, we looked at how the frequency of most extreme tropical cyclones will change due to climate change. Global warming will more than double the likelihood of strong cyclones for many areas by 2050. As a result, tropical areas that are already vulnerable to climate change due to sea level rise may also experience more intense tropical cyclones/hurricanes, which could further increase the risks of weather extremes and flooding.”
The analysis shows the frequency of the most intense cyclones, those from Category 3 or higher, will increase globally due to climate change, while weaker tropical cyclones and tropical storms will become less common in most of the world’s regions, with the only exception of the Bay of Bengal.
Many of the most at risk locations will be in low-income countries. Countries where tropical cyclones are relatively rare today will see an increased risk in the coming years, including Cambodia, Laos, Mozambique and many Pacific Island Nations, such as the Solomon Islands and Tonga. Globally, Asia will see the largest increase in the number of people exposed to tropical cyclones, with additional millions exposed in China, Japan, South Korea and Vietnam.
The study could help governments and organisations better assess the risk from tropical cyclones, thereby supporting the development of risk mitigation strategies to minimise impacts and loss of life.