Could the Frequency of Hurricanes Double or Triple in the Coming Decades From Climate Warming?

Check out this answer from Consensus:

While the overall number of hurricanes may not increase, the frequency of the most intense hurricanes (Category 4 and 5) is projected to nearly double by the end of the 21st century. Additionally, the frequency of major hurricane landfalls in the U.S. is expected to rise with increased anthropogenic warming. These findings suggest that climate warming could lead to more frequent and severe hurricane events, particularly in the western Atlantic and U.S. coastal regions.

The potential impact of climate warming on the frequency and intensity of hurricanes is a critical area of research, given the significant implications for coastal communities and disaster preparedness. This synthesis examines whether the frequency of hurricanes could double or triple in the coming decades due to climate warming, based on findings from recent research papers.

Key Insights

• Increase in Intense Hurricanes:
  • Several models predict a decrease in the overall number of hurricanes but an increase in the frequency of the most intense storms (Category 4 and 5) by the end of the 21st century1.
  • The largest increase in intense hurricane frequency is projected in the western Atlantic region, suggesting higher risks for areas like Hispaniola, the Bahamas, and the Southeast coast of the United States1.
• Major Hurricane Landfall Frequency:
  • Anthropogenic climate change, driven by increased greenhouse gases, is associated with fewer long-duration major hurricane landfall droughts in the U.S., implying an increase in the frequency of major hurricane landfalls2.
  • The use of high-resolution climate models indicates that greater anthropogenic warming could lead to more frequent major hurricane landfalls, posing a substantial threat to U.S. coastal communities2.

Could the frequency of hurricanes double or triple in the coming decades from climate warming?

Kevin Trenberth has answered Unlikely

An expert from National Center for Atmospheric Research in Climate science

It may depend a bit on how you count: what threshold you use for the event. As already observed, we expect with global warming an increase in tropical storm activity.  But “activity” can be manifested in various ways. It can lead to more storms, more intense storms, bigger storms, longer lasting storms, more rainfall, and changed tracks.

In general we expect more intense, bigger and longer lasting storms, but actually fewer storms overall, and not much change in tracks.  The tracks are dominated by the weather situation (jet stream, high and low pressure systems, cold fronts etc). Because of the increase in tensity, we do expect more very intense storms cat 3 and above. But we expect fewer storms overall. The reason is that each storm takes energy out of the ocean and mixes the ocean, and the big storms do so more than little storms: one big storm can take the place of 4 or 6 smaller storms in this regard. Also there is expected an increase in the stability of the atmosphere that may help suppress smaller storms, but when conditions are ripe and the storms break through, they are apt to be more intense. 

You may find this article useful

Trenberth, K. E., 2007: Warmer oceans, stronger hurricanes. Scientific American, July, 2007, 45-51 [PDF]

Could the frequency of hurricanes double or triple in the coming decades from climate warming?

Kerry Emanuel has answered Unlikely

An expert from Massachusetts Institute of Technology in Atmospheric Science

This is a poorly posed question. We actually expect the overall frequency of hurricanes to decline slightly as the climate warms. On the other hand, the very high intensity and heavy rainfall events are expected to increase, and there is some evidence that they are increasing. For example, we believe that the probability of Hurricane Harvey’s extraordinary rainfall in Texas was increased by roughly a factor of four over its probability in the late 20th century, as a consequence of global warming.

Could the frequency of hurricanes double or triple in the coming decades from climate warming?

Philip Klotzbach has answered Unlikely

An expert from Colorado State University in Atmospheric Science

I think there is very little scientific evidence that such an increase in overall hurricane numbers would occur. Most of the dispute in the scientific community is if hurricanes will get stronger due to climate warming, not more frequent. 

Given that the trend in global temperatures has certainly been up since 1970, we would expect to have already seen an increase in the overall number of hurricanes if climate change were dramatically impacting hurricane numbers. But, this lack of trend in hurricane totals is consistent with what was published in Nature Geoscience in a recent review paper on tropical cyclones and climate change

Some observational studies do show an increase in hurricane intensity, that is, the strongest storms are getting stronger, but the interpretation of these studies is a bit challenging, since our observational network for monitoring hurricanes has generally improved with time. In general, the better our observational network, the better is our ability to measure storms at all intensities.

NOAA’s Geophysical Fluid Dynamics Laboratory also has a nice summary on the current state of the science when it comes to hurricanes and climate change:

https://www.gfdl.noaa.gov/global-warming-and-hurricanes/

Could the frequency of hurricanes double or triple in the coming decades from climate warming?

Sergey  Gulev has answered Unlikely

An expert from Sea Atmosphere Interaction Laboratory in Atmospheric Science

It is important to be specific in the words we use to talk about this: ‘hurricane’ refers specifically to North Atlantic and eastern North Pacific tropical cyclones. ‘Frequency’ refers to the number of hurricanes (or more generally tropical cyclones elsewhere in the world) that form in a given region, the North Atlantic for example. Generally, it is important to specify which region (usually referred to as a ‘basin’) is being discussed since tropical cyclone activity is quite variable from region to region and across both hemispheres.

The ‘frequency question’ is one of three major lines of physical research in the overall question about how tropical cyclone activity will change in the future. The other two being intensity (how strong they are) and tracks (where they form and then travel). Of course changes in one of these aspects can, and likely will, project on to another. For example, if hurricane tracks in the North Atlantic were to change, it could be that local frequency of hurricanes at a particular site of interest could indeed dramatically increase, while the frequency over the entire basin could be declining.

Aside from questions of hurricane and climate physics, the ‘destructiveness’ of hurricanes is also a key area of interest and is generally more relevant to the public. This is in fact a more complex issue since it is related to exposure, which is a function of population, building standards, infrastructure and policy in addition to the physics.

When discussing hurricanes and climate change, these four distinctions (frequency, intensity, track, and destructiveness) are very important. Particularly because hurricanes (especially major hurricanes) are sparse events, with approximately 8 occurring in the North Atlantic in a given year. The typical diameter of hurricane strength winds (over 70 mph) is around 100 miles, the exposed coastline from South Mexico to Maine is around 4500 miles, so generally a careful consideration of these distinctions and their local effects should be made.

Taking the question at hand to mean: ‘Could the number of hurricanes in the North Atlantic overall double or triple in the coming decades from climate warming’, the answer is that this is unlikely.

Most models (simulations based on our current understanding of physics and computing capacity) project a decrease in hurricane frequency towards the end of the century (assuming a not-overly optimistic, not-overly pessimistic projection of future greenhouse gas emissions). However, they also predict an increase in the average intensity of hurricanes of between 2 and 11% (see Knutson et al. 2013). Overall this would result in a corresponding increase in the seasonal-average destructiveness of hurricanes.

Globally there is a greater than 50% chance that climate warming will result in an increase in the number of the most intense tropical cyclones (wind speed greater than 130 mps) (see Bender et al. 2010). This increase is projected to be over 90% but a doubling or tripling on the time scales of decades is very unlikely and models suggest that this increase will only be detectable after 2050. Moreover, we have particularly low confidence in these projections specifically for the North Atlantic.

Finally, it is important to consider that we are talking about averages over seasons. It is quite possible that in any given year, a particular location might experience 2 or 3 hurricanes while the long-term average is 1. It is this fact that is particularly concerning and should motivate a response from the public. Since this particular location may well be a site of high population. Sites with high populations are well correlated with high poverty rates as well as being locations for critical infrastructure and national sympathy. Thus such a chance is not worth taking.

*This answer was compiled in collaboration with Josh Studholme*

Could the frequency of hurricanes double or triple in the coming decades from climate warming?

James Done has answered Unlikely

An expert from National Center for Atmospheric Research in Climatology

I’m the scientist who made the original claim in the Guardian article that the frequency of the high intensity hurricanes could increase in the future so thank you for this opportunity to explain the broader context.

We know there are a number of factors that will affect future tropical cyclone frequency. A majority of studies find a future reduction in overall numbers, a future increase in average intensity and a shift in the frequency distribution towards the very high intensity events. Some recent work has also suggested a future increase in the latitude of the lifetime peak intensity. The net effect of all these expected changes for a given region is unclear. It’s therefore possible that some regions may experience increases in the numbers of high-intensity hurricanes, particularly those regions at the edges of the geographic limits of high-intensity hurricanes in today’s climate.

Could the frequency of hurricanes double or triple in the coming decades from climate warming?

Michael Wehner has answered Extremely Unlikely

An expert from Lawrence Berkeley National Laboratory in Climatology

I feel it is extremely unlikely that the number of tropical cyclones in any basin will double even under scenarios with no policies to reduce the emission of greenhouse gases. Whether the number of named tropical storms increases or decreases is a very active research question. Many tropical cyclone permitting climate model simulations project decreases in the number of weaker storms and increaes in the number of intense (category 4 and 5) storms. Since there are so many more weak storms than strong storms, the total number would decrease. However, the explanations for these projections is less than satisfying and a few climate models show increases in the total global number of named storms. However, doubling or tripling is far beyond any current credible simulation.