Tropical Cyclones - "Doing the Lord's Work" v Reality

A non-technical review of current trends and the future

Recent Trends

Here’s what most people know about trends in tropical cyclones -

1. Tropical cyclones (TCs) are becoming more intense

2. Damages from TCs are “off the charts”

3. Rainfall from TCs is increasing, leading to more flooding

Climate scientists have educated the public well. All these things are true. It sounds terrifying.

Here’s the more complete version of what tropical cyclone experts know.

1. There are 40 years of satellite observations of TCs out over the ocean. 40 years isn’t very long in climate terms, but it’s all we have. Over the oceans TCs have become more intense over this period.

2. Damages from TCs in the US have massively increased because there has been a huge growth in property values along the coast in regions where TCs strike (the population of Florida, for example, has increased almost 50 times since 1900). Adjust for the increase in property values and there is no change.

3. Rainfall from TCs has probably increased, but there’s no data. It’s probably true because warmer air holds more moisture.

4. There is almost a century and a half of good quality data on severe TCs hitting the coast of the US and the east coast of Australia (no good quality century-scale data for other regions). Over this time, the US has seen a small decrease and Australia has seen a large decrease (currently unexplained).

5. For the 40 years of satellite observations, total energy from TCs over the oceans has decreased.

Note - a few people might wonder how #1 and #5 can both be true. Easy to explain - categories 4 and 5 (the worst) TCs are occurring at the same rate. The lesser TCs (categories 1-3) have reduced in frequency. This means total energy has dropped but the proportion of the highest energy TCs has increased.

All these things are true. It doesn’t sound terrifying.

It’s easy to demonstrate that this is actually what TC experts believe.

The key to misinformation is the missing information.

The Future

There’s a theory from Kerry Emanuel, top TC expert, that the theoretical maximum wind speed of TCs will increase with higher temperatures. Many TC researchers see this as true, or at least, a useful guide to what might happen. Some dispute the theory.

The theory doesn’t say how many TCs will reach this theoretical maximum.

Climate scientists have run climate models out to 2100 and looked at how much this theoretical maximum might increase.

For a scenario where we carry on burning fossil fuels at approximately the current rate (RCP6), for the location on the planet this maximum increases the most, it’s 5% across a century. The energy from TCs increase disproportionately, so total energy would increase by about 15%.

• “Not dramatic”, words from a paper discussing the results

For a scenario where we have a massive increase in burning fossil fuels (RCP8.5 - the gift that keeps on giving), a scenario with 5-6x as much coal burnt by the end of the century compared with today, it’s over 30%, with total energy in these TCs increasing by two and a half times.

• Apocalyptic

I doubt that anyone reading climate scientists in the media has heard these scenarios contrasted.

How will the frequency of TCs change as the planet warms? No one knows. There are lots of hopeful comments in papers through the last couple of decades about progress in modeling TCs, but as Adam Sobel, a luminary in the field, said in 2021:

The state of the science is not great. There are around 80 tropical cyclones in a typical year, and we do not know why it is this number and not a much larger or smaller one.

We also do not know much about whether this number should increase or decrease as the planet warms - thus far, it has not done much of either on the global scale, though there are larger changes in some particular regions.

No existing theory predicts tropical cyclone frequency.

Finally, in the words of Kerry Emanuel in 2025, probably the most cited author on TCs:

The total hazard — the geophysical component of risk, comprising the probabilities of hurricanes with given levels of wind, rain and storm surges — remains hard to evaluate. The literature is unclear as to whether risks overall will worsen or even diminish, let alone by how much.

Good luck finding this kind of information in the media.

Conclusion

“We don’t know” is a good reason to highlight the risk of warming the planet. That’s the current science from tropical cyclones.

Recent trends in TCs include some good news and some bad news.

But that’s not the message in the media. The evangelical version dominates.

Unfortunately, you can’t rely on the experts to tell you the expert opinion.