September 11, 2017

expert reaction to Hurricane Irma hitting Florida

Having hit large swathes of the Caribbean, Hurricane Irma is now working it’s way up the West Coast of Florida.

Dr Phillip Williamson, NERC Science Coordinator at University of East Anglia, said:

“Perhaps Harvey was happenstance, and Irma could be coincidence.  But Jose following close behind has to be climate change in action.  Damaging hurricanes, cyclones and typhoons occur in tropical parts of the world, at the time of year when the sea is warmest.  So if the world gets warmer still, the risk increases – it’s as simple as that.

“In particular, when one follows much the same track as another, soon afterwards, the second or third is usually likely to be weaker – since the surface ocean will have been cooled by the initial mixing (bringing deeper, lower-temperature water to the surface).  But that effect won’t happen, or will be much less, if there’s warm water at depth as well as at in the uppermost layers.  Here we see there has been some overlap of the ‘flight paths’ of Harvey, Irma and Jose, yet without resulting in any substantive reduction in their strengths, all being at least category 4.”

Prof. Dave Reay, Professor of Carbon Management at the University of Edinburgh, said:

“Climate change may not have caused Hurricane Irma, but it is making its impacts a whole lot worse. Rising sea levels and a warmer, wetter atmosphere are combining to intensify flood risks all around the world. President Trump said he withdrew the US from the Paris Climate Agreement to protect jobs and businesses. For many folk in Texas and Florida that decision must now be looking pretty short-sighted.”

Dr Sally Brown, Senior Research Fellow at the University of Southampton, said:

“Whilst Tampa has a much higher population and more buildings than Caribbean Islands, it has more substantial buildings which are hit by lower wind speeds now Irma is a category 4 hurricane. Damage, whilst substantial, is likely to be relatively less.

“The wider Tampa-St Petersburg area had more than 400,000 people exposed to a 1-in-100 year coast flooding in 2005, and with climate change alone, this number could increase by a quarter in the 2070s. Today, thousands will be affected by flooding, and many hundreds of thousands more will be affected by the high winds and rain from the hurricane.”

Reference:

Hanson, S., Nicholls, R. J., Patmore, N., Hallegatte, S., Corfee-Morlot, J., Herweijer, C., & Chateau, J. (2011). A global ranking of port cities with high exposure to climate extremes <https://eprints.soton.ac.uk/cgi/eprintbypureuuid?uuid=66fa9a4a-77d3-4a73-8fe5-c34cb5718ab9>. Climatic Change, 140(1), 89-111. DOI: 10.1007/s10584-010-9977-4 <http://dx.doi.org/10.1007/s10584-010-9977-4>

Prof. Chris Huntingford, from the UK Centre for Ecology and Hydrology, said:

“Understanding which weather extremes are changing location or increasing in intensity under global warming is a challenge climate science must address in full. One barrier to progress is it will involve running computationally intensive computer models, and thousands of times, to capture the statistics of relatively rare events.

“Partnerships between commercial companies operating vast cloud computing services and research centres developing climate models might be an avenue worth pursuing.”

Dr. Jeffrey S. Kargel, Department of Hydrology & Atmospheric Sciences at the University of Arizona, said:

“As we have been hearing on the news, Hurricane Irma restrengthens every time the eye passes over warmer patches of water.  The relationship between hurricane strength and sea surface temperature has been known for a long time, and this basic fact underscores the ongoing impact of climate change on hurricane strength. The hazards due to hurricanes and the effects of climate change on a wide range of extreme weather phenomena isn’t just a coastal concern.  Extreme weather affects every place on the globe.  In 2014 I was at 16,000 feet elevation, over 400 miles inland near the base of Mount Everest, and my team in land-locked Nepal was hit by the soaking remnants of Extremely Severe Tropical Cyclone HudHud.  In addition to many killed in the coastal areas, over 42 nearby trekkers and mountaineers were killed by the storm’s severe, unseasonal snowfall– a bizarre raging thundersnowstorm as I experienced.

“The reach of extreme weather is spreading and its punch is getting stronger due to climate change.  No individual meteorological event is attributable exclusively to shifting climate, but human alteration of the atmosphere is having a major role in causing more costly and more frequent extreme weather events.  Poor nations pay mostly in bodies, and wealthier, more developed nations pay more in damaged stuff, but there comes a point when no amount of weatherproofing can protect people.

“Science has never been more needed and more available to contribute to smarter economic development, such as in the energy sector, and construction designs built on scientific understanding of flood and wind hazards, water policies designed for resilience to floods and droughts, forest management to handle diminishing snowpack and spreading droughts in some places and in other places increasing precipitation, and mountain development zoning to deal with changing mountain hazards such as glacial lake outburst floods. To make effective use of the sustained public investment in science we need politicians and decision makers who are able to recognize the value of science and technology to help us understand the human role in climate change and what we can do to reduce it and adapt to it.”

Dr Dann Mitchell, lecturer in Climate Physics at the University of Bristol, said:

“As Irma makes landfall in Florida, comparisons are being drawn with one of the previously most devastating hurricanes in that area, Hurricane Andrew, which hit Florida in 1992. Irma is almost 30% larger than Andrew, and will impact Florida for far longer due to its path. The wind speeds could be around 150mph, and the funnelling of wind between Miami’s tall buildings could result in even stronger winds.

“Increased intensity of storms is an expected climate change signature, but it is too early to tell if this particular storm was enhanced in this way.”

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

“Hurricanes, or tropical cyclones, require a set of atmospheric ingredients to form. Warm upper ocean water provides the most vital Hurricane fodder, energy and water. But changes in wind and moisture with altitude are also key and the rotation of the Earth increasingly spins these storms up as they travel away from the equator.

“Especially strong seasonal warming this year combined with the other factors mentioned, partly relating to natural ocean fluctuations, have made conditions ripe for tropical cyclones to form in the Atlantic. While weather explains the formation and track of these tropical beasts, additional heating due to emissions of greenhouse gases from human activities will inevitably make them more deadly. Extra energy from warmer waters increases the intensity of the winds in the strongest cyclones while a warmer atmosphere is able to suck in greater quantities of moisture which is dumped as more intense rainfall. Rising sea level due to oceans expanding as they warm and more ice melt from glaciers and ice sheets on land add to the size of ocean storm surges. These can devastate low-lying coastal regions including low-lying islands such as Caribbean Islands and the Florida Keys. So while the fickle nature of the atmosphere and ocean have generated deadly storms this year, their impacts have been amplified by human-caused climate change.

“There will be a continued threat from these events in the future to warm, tropical coasts such as the Caribbean and Florida. While there is not clear evidence to suggest an increase in the frequency of all tropical cyclones in the future, warming of the planet will generate more intense rainfall, stronger winds and more massive storm surges when intense tropical cyclones form and it is expected that there will be more super-charged tropical cyclones or Hurricanes as the planet continues to heat up.”

Dr Ed Hawkins, Climate research scientist at the University of Reading, said:

“Relative sea levels in Key West have risen around 30cm in the past century, likely making the storm surge from Hurricane Irma worse than would otherwise have been the case. Some of the relative sea level rise is due to the sinking land, but most is due to the warming, expanding oceans.”

A spiral graphic can be seen here: https://twitter.com/ed_hawkins/status/906852782501744641

All our previous output on this subject can be seen at this weblink:

http://www.sciencemediacentre.org/expert-reaction-to-hurricane-irma/

Declared interests

None declared