October 9, 2024

expert reaction to Hurricane Milton

Scientists comment on Hurricane Milton in the Gulf of Mexico. 

Dr Karsten Haustein, Climate Scientist, Leipzig University, said:

How does climate change impact extreme weather?

 “Human-caused climate change does not only increase the risk for strong hurricanes to occur, but it also makes droughts, heatwaves and heavy rainfall much more likely in many regions of the globe.

 Is climate change making hurricanes more common/worse?

 “The total number of hurricanes is not expected to change, but the number of very strong hurricanes (Category 4 or 5) is! Hurricanes require a moist atmosphere, warm ocean temperature and little wind shear. The latter is expected to increase as well, hampering the initial formation of hurricanes, hence limiting the total number of tropical storms. But if conditions are such that they can form, hurricanes tend to grow stronger quicker. Milton has been the perfect example. Both, the increase in Cat 4 and 5 hurricanes as well as the ‘explosiveness’ with which they grow can be demonstrated in the observational record by now.

How does Hurricane Milton compare to others in the region?

“Milton was the 5th strongest hurricane in terms of minimum core pressure (897 hPa) and the 2nd strongest in terms of ‘explosiveness’ (24 hour pressure drop of 77 hPa) in its earlier stages. It did hit Florida’s west coast as a Category 3 hurricane.

What is particularly worrying about this hurricane?

“The storm surge brought about by Milton is (or was) the main worry. Wind speeds did cause considerable damage, but not to the extent that Cat 4 or 5 storms would have. Tampa in particular did escape the most severe impacts this time around, whereas St Petersburg and Sarasota did see substantial wind damage.

What are the impacts likely to be for Florida/how severe are the impacts expected to be?

“Extreme flooding was expected to be the most destructive consequence – with impacts felt at coastal or near-coastal residences. However, as things seem to stand at the moment, the slightly faster progression of Milton before landfall might have saved many properties from larger damage as peak surge did not coincide with high tide. Rainfall amounts were largest north of Milton’s eyewall where winds were a tad less damaging. So overall perhaps no catastrophic outcome, yet Milton did cost lives and caused major flooding and damage along its path.

How long is this hurricane expected to last?

“The hurricane has weakened fairly rapidly while moving over Florida and is now a tropical storm over the Atlantic with no further danger for Florida or other populated regions.”

Prof Richard Allan, Professor of Climate Science, University of Reading, said:

“Warming of climate is increasing the damage wrought by tropical cyclones like Hurricane Milton. The fiercest tropical cyclones are becoming more frequent as they tap into more copious energy supplied by hotter oceans. These can whip up greater storm surges that are compounded by rising sea levels and greater volumes of rainfall fuelled by the warmer, moister atmosphere, leading to more devastating and widespread flooding. It’s only by taking action to deliver massive and rapid cuts in our global emissions of greenhouse gases that we can limit the growing severity of extreme weather events.”

Prof Tim Palmer, Royal Society Research Professor, University of Oxford, said:

“There have been lots of stories about how climate change is making Hurricanes like Milton more likely – the warm sea surface temperatures (SSTs) in the Gulf of Mexico being an important contributing factor. 

“However, there is something important about the link between climate change and hurricanes we understand less well. Currently the El Nino SSTs in the Pacific are weakly negative – consistent with a weak state of La Nina. These remote factors are important in determining whether a given hurricane season will be strong or not. El Ninos tend to supress hurricanes, La Ninas exacerbate them. 

“Hence a key question for how climate change will impact on Atlantic hurricanes is how climate change is affecting the likelihood of El Nino or La Nina conditions in the Pacific. This is a very complex question involving coupled ocean atmosphere dynamics. The current generation of models to do not agree on whether El Ninos or La Ninas will become more commonplace. 

“My own view is that this type of important question (how does climate change affect ocean and atmosphere circulation patterns globally) can only be answered with much higher resolution models than we currently have. I have been calling for  a “CERN for Climate Change” to address this issue.”

Comments from Thursday 9th October: 

Dr Helen Hooker, Flooding, Climate Change and Tropical Cyclones Research Scientist, University of Reading, said:

“Hurricane Milton formed in the Gulf of Mexico, which is experiencing record-breaking ocean temperatures.

“Milton developed incredibly quickly and rapidly intensified into a Category 5 hurricane. A drop of around 47 millibars was recorded in just 7 hours, making Milton the most rapidly intensifying hurricane since Wilma in 2005.

“Climate change has contributed in three main ways to the worsening impacts of hurricanes:

“By increasing ocean temperatures as they absorb heat from the atmosphere, giving extra energy to the storm. This contributes to rapid intensification and a higher category hurricane with stronger wind speeds.

“Sea levels have already risen and will continue to do so, making storm surge impacts worse. Higher water levels will penetrate further inland, affecting more people.

“Our warmer atmosphere holds more water, meaning heavier rainfall. More intense rainfall on top of a higher storm surge combines to worsen impacts.”

Dr Xiangbo Feng, Joint Research Scientist in Tropical Cyclones, University of Reading, said:

How does climate change impact extreme weather?

“Climate change influences extreme weather via different pathways.

1. Climate change alters the mean state of our climate system. For example, it can make the surface air temperature warmer that allows the air to be able to hold more moisture (that means potential rainfall could be heavier once conditions for a phase change are met), and change the large-scale background atmospheric circulations in which extreme weathers are embedded (this can shift extreme events to some unusual places or change the propagation of extreme weather systems). 
2. Climate change also changes appearance of extreme weather, such as the frequency, intensity, and persistence. Large-scale extreme weather (e.g. hurricanes) is usually triggered by somehow small-scale disturbances, which stochastically occur in our Earth climate system. With climate change, the climate system has higher instability, and this would generate more finer-scale disturbances that will seed extreme weather. 

Is climate change making hurricanes more common/worse?

“Climate science research finds that the current climate change pattern is shifting the number of hurricanes in the north Atlantic further higher up. This upward trend is clearly seen in observations over the past 4-5 decades. Our warming climate also strengthens the intensity of tropical storms. It is likely that the proportion of major hurricanes will increase in the future with the warming trend. Note that there is still uncertainty in the frequency and intensity of hurricane for the future. But, for sure, climate change will worsen the impacts of hurricanes, such as excessive rainfall, and storm surges and high waves related to mean sea level rise. 

How does Hurricane Milton compare to others in the region?

“In North Atlantic, since 1960, a CAT5 hurricane is seen about every two years. What makes Hurricane Milton stand out is its location when it reaches and maintains such high strength. It is very rare to see a CAT5 hurricane appearing in Gulf of Mexico. Hurricane Milton also has a very slow traveling speed. This allows the storm to stay longer over the ocean and extract sufficient energy from the sea in order to maintain such strength. But this may also mean longer time for people to prepare and mitigate the impact.

What is particularly worrying about this hurricane?

“It is how long the high intensity will last. Because the ocean, Gulf of Mexico, has been warmed for months, there are plenty of heat energy available underneath. Also, the steering flow has been slow, which may help hold Hurricane Milton for a longer time over the warm ocean. It will be even more worrying if the upper-level westerly winds become stronger and shear to south during this period, which, in this case, will further strength the hurricane system related to stronger vertical temperature gradient.”

Prof Ilan Kelman, Professor of Disasters and Health, University College London, said:

“Florida should have been braced for catastrophic impacts from Hurricane Milton, especially storm surge and rainfall flooding. The possible disaster is sadly unsurprising, since Florida sits in the usual hurricane zone and it is now hurricane season. Yet the state permitted building development in dangerous locations and does not always support people who need help over the long-term to be ready for hazards.

“Human-caused climate change is strengthening hurricanes while reducing their frequency. Hurricane Milton shows exactly the climate change influence we would expect from higher storm intensity.

“Given Florida’s hurricane history including previous storms in this area in 1848, 1921, and 1946, they should have been much more prepared over the long-term. Planning decisions creating dangers and long-term lack of services to assist people who cannot help themselves for known hazards are all about choices to make disasters.”

Prof Liz Stephens, Professor in Climate Risks and Resilience, University of Reading, said:

“The wide area of intense winds and rainfall from Hurricane Milton will mean that many communities in Florida who are still recovering from the impacts of Hurricane Helene will be affected again by this latest storm, even though Milton is expected to make landfall further south.

“Hurricane Milton is forecasted to track across Florida and out into the North Atlantic Ocean. This means that we are not expecting to see the same flash flooding and mudslide impacts as Helene in areas such as the Appalachian mountains, caused by Helene decaying over land.

“Rising sea surface temperatures as a result of climate change are fuelling the intensity of hurricanes, and the warmer atmosphere can carry more water. This means that the storms which do form are becoming more impactful.

“Further research is needed to understand how the risk of consecutive hurricanes is changing, as these clusters of events can greatly stretch resources for emergency preparedness and response.”

Prof Hannah Cloke, Professor of Hydrology, University of Reading, said:

“Hurricane winds grab people’s attention, but flooding is probably the biggest concern with Milton. Winds of 150mph can easily destroy buildings and cause injuries and fatalities if people are caught out in the open by flying debris. 

 “There are three types of floods that cause the biggest damage – storm surge causing coastal flooding, flash floods from the extremely heavy rain, and river floods as all that water rushes down channels and onto floodplains. 

 “People’s attention may be turned to the sky, but emergency planners will be worried about what is coming from below.”

Prof John Marsham, Professor of Atmospheric Science, University of Leeds, said:

How does climate change impact extreme weather?

“Weather extremes increase rapidly for even apparently small increases in global temperature – this is true for heatwaves, floods, droughts and intensity of hurricanes.

Is climate change making hurricanes more common/worse?

“Many aspects of Helene and Milton are absolutely what we expect from climate change – hurricanes need warm oceans to form, and record-breaking ocean temperatures are fuelling these devastating storms. Warm air holds more water, giving heavier rain and more flooding. Increased sea-levels from climate change give more coastal flooding when hurricanes create a temporary “storm surge” rise in sea level. Finally, climate change can give shorter gaps between extreme events allowing less time to recover – we’re now seeing people affected by Helene now having to prepare for Milton. If we rapidly phase out fossil fuels, we can stop these extremes getting much worse but will have to continue to cope with the new climate we have created and will likely have to cope with rising sea levels for centuries.

What is particularly worrying about this hurricane?

“As a climate scientist, and a parent, every extreme weather event is now a reminder of the catastrophe we will face if we do not rapidly phase out fossil fuels. The tragedy is that climate scientists have been warning of this for decades. Rapid action is critical. Most people in the UK want more action on climate change and underestimate how much other people do. We have solutions and rapid action will save trillions.”

Declared interests:

Prof Ilan Kelman: No interests to declare

Prof Liz Stephens: “I also work for the Red Cross Red Crescent Climate Centre”

Prof John Marsham: “I receive funding from UKRI, FCDO and the Met Office”

Prof Hannah Cloke: “works with and advises the Met Office, ECMWF and Environment Agency.”

Dr Xiangbo Feng: Nothing to declare

Prof Richard Allan: No interests to declare.

Prof Tim Palmer: No interests to declare.

Dr Karsten Haustein: No interests to declare.