This year’s hurricane season could once again be exceptionally active. For the third consecutive year, the main phase of the stormy season in late summer will likely be characterised by climatic conditions that are favourable for storm formation over the North Atlantic. The last such string of years with these La Niña conditions was in 1998-2000.
Is climate change affecting tropical cyclones?
Storm activity is chiefly influenced by two factors:
- Firstly, by the sea surface temperature in the tropical North Atlantic. According to the latest forecasts, this year the temperature will be average or higher, which favours storm development.
- Secondly: by the naturally occurring ENSO (El Niño Southern Oscillation) climate oscillation in the Pacific. Under La Niña conditions, there are normally weaker easterly winds in the upper atmosphere over the tropical North Atlantic and the Caribbean. The lessening of wind shear facilitates the formation of tropical cyclones. In contrast, storm activity tends to be subdued during El Niño phases. Forecasting centres find it unlikely that we will see a switch from the current La Niña conditions to a storm-dampening El Niño phase. In fact, just the opposite seems more likely.
- Climate change is affecting more than just water temperatures. The research to date indicates that, while climate change does not tend to cause more tropical cyclones, it does cause more frequent severe hurricanes with destructive winds and storms with rainfall extremes.
Given the enormous potential losses, it is essential that we have a precise grasp of hurricane-related risks. Accordingly, our staff includes a range of meteorologists and climate researchers. In this way, we can support our society and economy with insurance covers, even when there are changes in risk, for instance due to climate change.
Hurricane damage costs billions
For comparison: in 2021 there were 21 tropical cyclones in the North Atlantic, including seven hurricanes and four major hurricanes rated category 3 to 5. The costliest tropical cyclone of the year was Hurricane Ida, which produced overall losses of US$ 65bn, of which US$ 36bn was insured. The previous year included a record-breaking hurricane season, with no less than 30 storms.
The ENSO conditions are also likely to influence the typhoon season in the Northwest Pacific, albeit with roughly the opposite effect. Consequently, Munich Re anticipates a level of storm activity that is slightly below the long-term average in the Northwest Pacific. From 1965 to 2021, the region was visited by an average of 25.9 tropical cyclones per year, including 16.2 typhoons and 8.8 especially powerful typhoons of categories 3 to 5.
Although Japan is normally home to the highest typhoon-related losses, we observe a trend towards increasing insured losses in China and India.