Water, Water, Everywhere: Sea Level Rise in Miami

Like many low-lying coastal cities around the world, Miami is threatened by rising seas.  Whether the majority of the cause is anthropogenic or natural, the end result is indisputable: sea level is rising and it is due to climate change.  It is not a political issue, nor does it matter if someone believes in it or not.

Tidal flooding on the corner of Dade Blvd and Purdy Ave in Miami Beach in 2010. (Steve Rothaus, Miami Herald)

The mean sea level has risen noticeably in the Miami and Miami Beach areas just in the past decade.  Flooding events are getting more frequent, and some areas flood during particularly high tides now: no rain or storm surge necessary.  Perhaps most alarming is that the rate of sea level rise is accelerating.

Diving Into Data

Certified measurements of sea level have been taken at the University of Miami’s Rosenstiel School on Virginia Key since 1996 (Virginia Key is a small island just south of Miami Beach and east of downtown Miami).  Simple linear trends drawn through annual averages of all high tides, low tides, and the mean sea level are shown below, and all three lines are about 4.5″ higher in 2013 than they were in 1996.

vk_annualZooming in to daily data, let’s look at two representative months (nothing unique about them): January 1996 and January 2014.  Tidal predictions are calculated to high accuracy using dozens of known astronomical factors, but do not account for non-astronomical factors such as weather or sea level rise.  In 1996, the observed water levels were typically close to the predicted values… sometimes slightly higher, sometimes slightly lower due to meteorological influences.  In January 2014, however, there was still variability, but the tides were always higher than predicted.

Verified hourly water heights at Virginia Key, Jan1-Jan 31.  (NOAA/NOS)

Predicted (blue) and observed (green) hourly water heights at Virginia Key, Jan1-Jan 31. (NOAA/NOS)

As eluded to in the introduction, sea level is not just rising here, the rate of the rise is accelerating.  For the following chart, only the daily high water mark (highest of the two high tides) for every day for 18+ years is plotted.  The water levels at high tides are the most relevant because that is when flooding events are prone to occur.  The data are color-coded by 5-year periods (pink is 2009-2014, green is 2004-2009, blue is 1999-2004, and purple is the remainder: 1996-1999).  There is plenty of daily and intra-annual variability of course, but what stands out is the increasing slopes of the linear trends.  Over the past 15 years, the average high tide has increased by 0.19″/year, but over just the past 5 years, the average high tide has increased at a rate of 0.67″/year. tide_data

Exposure

The Miami metropolitan region has the greatest amount of exposed financial assets and 4th-largest population vulnerable to sea level rise in the world.  The only other cities with a higher combined (financial assets and population) risk are Hong Kong and Calcutta [1].

Using a sea level rise projection of 3 feet by 2100 from the 5th IPCC Report [2] and elevation/inundation data, a map showing the resulting inundation is shown below.  The areas shaded in blue would be flooded during routine high tides, and very easily flooded by rain during lower tides.  Perhaps the forecast is too aggressive, but maybe not... we simply do not know with high confidence what sea level will do in the coming century.  But we do know that it is rising and showing no sign of slowing down.

Map showing areas of inundation by three feet of sea level rise, which is projected to occur by 2100. (NOAA)

Map showing areas of inundation by three feet of sea level rise, which is projected to occur by 2100. (NOAA)

An Attack from Below

In addition to surface flooding, there is trouble brewing below the surface too.  That trouble is called saltwater intrusion, and it is already taking place along coastal communities in south Florida. Saltwater intrusion occurs when saltwater from the ocean or bay advances further into the porous limestone aquifer.  That aquifer also happens to supply about 90% of south Florida's drinking water.  Municipal wells pump fresh water up from the aquifer for residential and agricultural use, but some cities have already had to shut down some wells because the water being pumped up was brackish (for example, Hallandale Beach has already closed 6 of its 8 wells due to saltwater contamination).

Schematic drawing of saltwater intrusion.  Sea level rise, water use, and rainfall all control the severity of the intrusion. (floridaswater.com)

Schematic drawing of saltwater intrusion. Sea level rise, water use, and rainfall all control the severity of the intrusion. (floridaswater.com)

The wedge of salt water advances and retreats naturally during the dry and rainy seasons, but the combination of fresh water extraction and sea level rise is drawing that wedge closer to land laterally and vertically.

In other words, the water table rises as sea level rises, so with higher sea level, the saltwater exerts more pressure on the fresh water in the aquifer, shoving the fresh water further away from the coast and upward toward the surface.

Map of the Miami area, where colors indicate the depth to the water table.  A lot of area is covered by 0-4 feet, including all of Miami Beach. (Dr. Keren Bolter)

Map of the Miami area, where colors indicate the depth to the water table. A lot of area is covered by 0-4 feet, including all of Miami Beach. (Keren Bolter, FAU)

An Ever-Changing Climate

To gain perspective on the distant future, we should examine the distant past.  Sea level has been rising for about 20,000 years, since the last glacial maximum.  There were periods of gradual rise, and periods of rapid rise (likely due to catastrophic collapse of ice sheets and massive interior lakes emptying into the ocean). During a brief period about 14,000 years ago, "Meltwater Pulse 1A", sea level rose over 20 times faster than the present rate. Globally, sea level has already risen about 400 feet, and is still rising.

Observed global sea level over the past 20,000 years... since the last glacial maximum. (Robert Rohde, Berkeley Earth).

Observed global sea level over the past 20,000 years... since the last glacial maximum. (Robert Rohde, Berkeley Earth).

With that sea level rise came drastically-changing coastlines.  Coastlines advance and retreat by dozens and even hundreds of miles as ice ages come and go (think of it like really slow, extreme tides).  If history is a guide, we could still have up to 100 feet of sea level rise to go... eventually.  During interglacial eras, the ocean has covered areas that are quite far from the coastline today.

Florida's coastline through the ages.  (Florida Geological Survey)

Florida's coastline through the ages. (Florida Geological Survey)

As environmental author Rachel Carson stated, "to understand the living present, and promise of the future, it is necessary to remember the past".

What Comes Next?

In the next 20 years, what should we reasonably expect in southeast Florida?  The median value of sea level from various observed trends in 2034 is around 6", with a realistic range of 3-12".

Year by year, flooding due to heavy rain, storm surge, and high tides will become more frequent and more severe.  Water tables will continue to rise, and saltwater intrusion will continue to contaminate fresh water supplies.

This is not an issue that will simply go away.  Even without any anthropogenic contributions, sea level will continue to rise, perhaps for thousands of years.  But anthropogenic contributions are speeding up the process, giving us less time to react and plan.

The entire region is already considered high-risk by insurance companies because of the hurricane threat, so at some point, this additional gradual threat will likely lead to extreme-risk properties being uninsurable.

Coastal cities were built relatively recently, without any knowledge of or regard for rising seas and evolving coastlines.  As sea level rises, coastlines will retreat inward. Sea level rise is a very serious issue for civilization, but getting everyone to take it seriously is a challenge.  As Dutch urban planner Steven Slabbers said, "Sea level rise is a ... storm surge in slow motion that never creates a sense of crisis".  It will take some creative, expensive, and aggressive planning to be able to adapt in the coming decades and centuries.

-----

Special thanks to Keren Bolter at Florida Atlantic University and Dr. Shimon Wdowinski at University of Miami for their inspiration and assistance.

1. http://www.businessinsider.com/cities-exposed-to-rising-sea-levels-2014-4

2. http://www.climatechange2013.org/images/report/WG1AR5_Chapter13_FINAL.pdf

 

CSTARS Study Evaluates Oil Spill Detection Tool

Scientists led by the Center for Southeastern Tropical Advanced Remote Sensing (CSTARS) of the University of Miami recently published an overview of synthetic aperture radar (SAR) as a tool to identify oil slicks on the ocean surface using satellite imagery.

SAR images were used to trace the areal extent of the Deepwater Horizon oil spill.

SAR images were used to trace the areal extent of the Deepwater Horizon oil spill.

The researchers outlined the “capabilities and shortcomings” of SAR to identify oil slicks that enter the marine environment through seeps, leaks, illegal discharge, and other industrial, transportation, or drilling accidents. They summarized the techniques used for identifying oil with SAR, the advanced capabilities of the newer programs and instruments, and the advancing potential for SAR to be used to monitor oceans for natural and illegal spills. The team published their findings in the June 2013 issue of OceanographyOil Spills and Slicks Imaged by Synthetic Aperture Radar.

Read more

Story reprinted courtesy of the Gulf of Mexico Research Initiaitve

Faculty and Student Honors & Awards

Professor Eberli Receives Distinguished Educator Award

UM Rosenstiel School Professor of Marine Geology and Geophysics Gregor Eberli is the recipient of the 2014 American Association of Petroleum Geologists (AAPG) Grover E. Murray Memorial Distinguished Educator Award “for being a superb teacher and mentor to young geoscientists and an educator to the industry and for his insightful and scholarly publications.”

UM Rosenstiel School Professor Gregor Eberli

UM Rosenstiel School Professor Gregor Eberli

A native of Switzerland, Dr. Eberli received his doctorate from the Swiss Institute of Technology (ETH) Zürich in 1985. In 1991 he joined the faculty of the UM Rosenstiel School, where he has been a principal advisor to over 20 doctoral and masters students and 12 post-doctoral students, as well as being associated with numerous other students through his teaching and as a research advisor. He is currently director of the CSL – Center for Carbonate Research, an association between oil companies and the University of Miami, which has been a model copied by numerous other universities. The mission of the Center is to conduct fundamental research in carbonates and to disseminate the results of this integrated research not only through academic journals but also directly to geoscientists working in companies.

Together with colleagues he leads high-quality field trips and short courses to industry geologists and engineers working for various companies from around the world. He co-led an AAPG Field Seminar to Great Bahama Bank for over a decade; the seminar is still run through the University of Miami and since its inception nearly 400 industry “students” have been introduced to carbonates with a major focus on stratigraphy and heterogeneity issues in carbonate reservoirs. He has been a distinguished lecturer for AAPG in 1996/97, JOI/USSAC in 1998/99, and the European Association of Geoscientists and Engineers in 2005-2006.

The AAPG Grover E. Murray Memorial Distinguished Educator Award is given in recognition of distinguished and outstanding contributions to geological education, including the teaching and counseling of students at the university level, and contributions to the education of the public, and management of educational programs. The award is presented at the AAPG annual meeting.

2013 Delcroix Prize in Oceans and Human Health

UM Rosenstiel School Professor Emerita Lora Fleming has been awarded the 2013 Delcroix Prize for her outstanding research in the field of oceans and human health.The prize will be awarded in Oostende, Belgium in June 2014, including a presentation from the laureate on her prize-winning research.

UM Professor Emerita Lora Fleming

UM Professor Emerita Lora Fleming

Prior to retiring from UM and joining the European Centre for Environment and Human Health at the University of Exeter, Fleming held a joint appointment at the UM Rosenstiel School and the UM Medical School and was co-director of the NSF-NIEHS Oceans and Human Health Center. She has created outreach and educational materials on the human health effects of marine and freshwater natural toxins, and performed research in Ciguatera Fish Poisoning, Florida Red Tides (Brevetoxins) and cyanobacterial toxins.

The Dr. Edouard Delcroix Prize is an international scientific prize awarded to a researcher or a research team for a scientific study on the links between oceans and human health. The prize was established in honor of Dr. Edouard Delcroix (1891-1973), Belgian orthopaedic surgeon and pioneer in thalassotherapy.

Rosenstiel School Student Goldwater Scholarship Honorable Mention

Joaquin Nunez received Honorable Mention from the Goldwater Scholarship Selection Committee. Nunez transferred to the Marine Science/Biology program in the Rosenstiel School in fall 2013, after earning an Associate’s degree in biology from Miami-Dade College – where he was involved with the National Science Foundation-funded STEM FYE program, which provides academic services to under-represented students in science, technology, engineering, and mathematics.

During his first semester at UM, Nunez joined the UM Rosenstiel School Laboratory of Marine Genomics, where he studies how genomes in the mummichog fish respond to changes in temperature. His work has implications for climate change and the global distribution of fish populations.

Associate Professor of Marine Biology Marjorie Oleksiak, who leads the marine genomics lab, wrote, “Mr. Nunez has proven to be responsible and dedicated, but also enthusiastic and curious.” She said that this “dedicated scholar” has an innate “ability to see a need or opportunity and act on it,” adding, “Often, what he does is above and beyond the call of duty.”

The Barry M. Goldwater Scholarship and Excellence in Education Program was established by Congress in 1986 to honor Senator Barry M. Goldwater, who served his country for 56 years as a soldier and statesman, including 30 years of service in the U.S. Senate.  The purpose of the foundation is to provide a continuing source of highly qualified scientists, mathematicians, and engineers by awarding scholarships to college students who intend to pursue careers in these fields. For more information, visit: www.act.org/goldwater 

The MPO Best Paper Award Goes To…

UM Rosenstiel School Ph.D. student Katinka Bellomo received the Best Paper Award from the Division of Meteorology and Physical Oceanography (MPO) for her research paper recently published in the American Meteorology Society’s Journal of Climate.

“Receiving the MPO best paper award is a huge personal satisfaction,” said Katinka. “This is the first paper of my dissertation and of my life.”

Addu Atoll lagoon at sunset

The paper, titled “Observational and Model Estimates of Cloud Amount Feedback over the Indian and Pacific Oceans,” addressed the largest uncertainty in climate models – cloud feedback – by examining observations of cloud cover taken from ships and satellites from 1954 to 2005. The results of this paper represent the first observational long-term estimate of cloud feedback.

In response to greenhouse gas forcing, the Earth would naturally cool off by emitting more radiation back into space. However, feedback mechanisms, from clouds, can increase or reduce this cooling rate.

“I am satisfied that the paper shows how to handle the uncertainties in observations and provides a methodology to estimate cloud feedbacks from these observations,” said Katinka.

Congrats Katinka!

At the Heart of a Hurricane Forecast

One of the many challenges in hurricane forecasting is incorporating observational data into forecast models. Data assimilation, as scientists refer to it, is the process of combining observational data – information obtained by satellites, radars or from instruments deployed into storms by aircraft – into a numerical weather prediction model.

Incorporating real-world temperature, wind, moisture or atmospheric pressure from multiple sources is a core component of hurricane science and vital to provide improved forecasts of both the track and intensity of storms. How to incorporate new types of observational information into a model is at the very heart of hurricane forecasting.

At the American Meteorology Society’s 31st annual Hurricane and Tropical Meteorology meeting in San Diego this week, Rosenstiel School Professor Sharan Majumdar discussed new approaches to improve data assimilation.

Typhoon Sinlaku (2008), as seen from Terra Satellite on September 10 2008. Credit: NASA

Typhoon Sinlaku (2008), as seen from Terra Satellite on September 10 2008. Credit: NASA

Citing the Ph.D. research of Rosenstiel School graduate student Ting-Chi Wu, Majumdar discussed the assimilation of temperature and moisture data obtained from satellite-based advanced Infrared (IR) soundings measured by polar-orbiting satellites of Typhoon Sinlaku during the 2008 Pacific typhoon season. Wu’s studied the period of storm intensification as Sinlaku intensified into a category-2 typhoon. Her conclusion was that the assimilation of temperature and moisture show promise in improving forecasts of hurricane and typhoon intensity, though more work needs to be done to improve their use.

Majumdar also provided an overview of strategies to assimilate observations to improve numerical weather forecasts of the track and structure of storms. He showed that targeted aircraft observations in select areas and satellite observations from both within and outside a tropical cyclone are beneficial.

Bite Size Wins Prize in Ocean Video Challenge

1397354_10152193972993265_1324283571_o Bite Size: Bull shark predation of tarpon from UM Rosenstiel School Research Assistant Professor Neil Hammerschlag and Gareth Burghes of Lagomorph Films claimed third place honors in the Ocean 180 video Challenge. This video highlights a collaborative research project with Rosenstiel researchers Dr. Jerry Ault and Dr. Jiangang Luo.

Using three-minute videos, ocean scientists explored a piece of their own recently published research, highlighting its significance and purpose.

To determine who was best at engaging and explaining these new discoveries, the Ocean 180 Video Challenge looked to a group of potential future scientists: a team of nearly 31,000 middle school students from around the world. Viewing each of the finalists, students were asked to evaluate the films for their clarity and message. They were also asked to consider which videos made them excited about the scientists’ research. After 5 weeks of classroom viewing, deliberation, discussion and voting, the three winners emerged.

“The competition is both a great opportunity to communicate our science as well as evaluate how our outreach efforts resonate with young audiences,” said Hammerschlag.

130504_110311_422_Divebar

Finalists had their videos viewed by thousands of classrooms around the world, exposing diverse and new audiences to their research. Students also provided scientists with feedback on how to improve their video storytelling and technical skills and ways to make science more relatable to the public.

For some middle school students, and budding scientists, sharing science might be the best part of Ocean 180. As one student judge explained, “It’s not very good to keep information that’s valuable to the world cooped up in a little box. You need to open the box and let everybody see it so they’re more aware of the environment and what’s in it.”

Sponsored by the Florida Center for Ocean Sciences Education Excellence (COSEE Florida) and funded through a grant from the National Science Foundation, the Ocean 180 Video Challenge was designed to inspire scientists to communicate the meaning and significance of scientific research with a broader audience.

Click here to learn more about the research study – Hammerschlag N, Luo J, Irschick DJ, Ault JS (2012) A Comparison of Spatial and Movement Patterns between Sympatric Predators: Bull Sharks (Carcharhinus leucas) and Atlantic Tarpon (Megalops atlanticus). PLoS ONE 7(9): e45958. doi:10.1371/journal.pone.0045958.

Tarpon

Photo credit: Joe Romeiro