Projections
The predictability of future tropical cyclones is marked with significant uncertainties due to several factors. These include disparities among climate models, the inherent complexity of processes incorporated into Tropical Cyclone Models, and regional variations in cyclone formation, behavior, and dispersal. Moreover, Tropical Cyclone Models are primarily calibrated for current climate conditions, which may introduce additional biases when applied to future scenarios. In summary, the complex and often conflicting interactions among ocean temperatures, wind patterns, and atmospheric conditions that drive cyclone formation, dispersal, and landfall remain poorly understood, making it challenging to identify which trends will dominate. For additional information on current understanding of tropical cyclones and tropical cyclone frequency, see Sobel et al. (2021). However, a few certainties do emerge in the projections. The clear trend of warming indicates that, once storms form and conditions become favorable, the intensities of these storms are likely to increase as compared to today. This signal is particularly pronounced for major tropical cyclones, as highlighted in the IPCC AR6 WG1 Report.
This page uses projections from the Columbia HAZard Model (CHAZ, Lee et al. 2018 ). These projections are derived from outputs of 12 CMIP6 GCMs under the SSP2-4.5 Scenario, focusing on the period 2035-2064 (centered on 2050). It’s important to note that the CHAZ model does not include projections for cyclone activity in the South Atlantic, based on the assumption that low cyclone activity will continue in the near future. Another important caveat is that CHAZ uses two configurations to represent moisture: the model with column relative humidity (CRH), used here, projects an increasing tropical cyclone frequency in the future, while the model using saturation deficit (SD) projects a decrease. In the Western North Pacific, cyclone frequency scales linearly with the rise in global mean surface temperature, highlighting a direct link to anthropogenic greenhouse gas radiative forcing. In the Atlantic, the SD experiments show the same trend, but the CRH response is more complex and nonlinear, likely due to the higher sensitivity of cyclones to aerosol forcing compared to greenhouse gas forcing. However, in both configurations, the percentage of intense cyclones is increasing, making this a consistent and reliable trend. For a review of tropical cyclone models, see Knutson et al. (2020).
Currently CCKP presents a single cyclone model, configuration, and scenario for the initial presentation of this complex subject matter.
CCKP is grateful for the expertise and guidance of the CHAZ Model Team at Columbia University.
Section I – Projected Tropical Cyclones Activity Maps
Below, you will find the projected exceedance probability distribution of tropical cyclones (number of cyclones per year) and the corresponding return period (pull-down menu), with levels ranging from blue (less frequent/less likely) to red (more frequent/more likely). By dragging the slider to the left, you can view the projected fractional change by 2050 compared to the historical period for cyclones of at least the selected category. Values below 1 indicate a decrease in storm frequency/probability (displayed in blue), while values above 1 indicate an increase (shown in red).
Data presentations on this page represent the modeled uncertainties by displaying the inter-model projected changes in the 10th percentile, median, and 90th percentile in the anomaly plots (on the right).
Section II – Comparison of Historical and Projected Cyclone Statistics
In the charts below, we compare the historical and projected simulated percentages and counts of cyclones across various categories. These comparisons are made at the global level, ocean basin level, Exclusive Economic Zone (EEZ), and at the country or territory level associated with the EEZ, reflecting the number of landfalls.
By default, the data is presented at the ocean basin level and for the primary EEZ linked to the selected country. However, users can choose other EEZs from the same country, as well as select additional EEZs from the map above. Since some EEZs span multiple basins, we default to show the primary ocean basin, but users can select additional basins that intersect with that EEZ as needed.