scholarly journals Tracking California’s sinking coast from space: Implications for relative sea-level rise

2020 ◽  
Vol 6 (31) ◽  
pp. eaba4551 ◽  
Author(s):  
Em Blackwell ◽  
Manoochehr Shirzaei ◽  
Chandrakanta Ojha ◽  
Susanna Werth

Coastal vertical land motion affects projections of sea-level rise, and subsidence exacerbates flooding hazards. Along the ~1350-km California coastline, records of high-resolution vertical land motion rates are scarce due to sparse instrumentation, and hazards to coastal communities are underestimated. Here, we considered a ~100-km-wide swath of land along California’s coast and performed a multitemporal interferometric synthetic aperture radar (InSAR) analysis of large datasets, obtaining estimates of vertical land motion rates for California’s entire coast at ~100-m dimensions—a ~1000-fold resolution improvement to the previous record. We estimate between 4.3 million and 8.7 million people in California’s coastal communities, including 460,000 to 805,000 in San Francisco, 8000 to 2,300,00 in Los Angeles, and 2,000,000 to 2,300,000 in San Diego, are exposed to subsidence. The unprecedented detail and submillimeter accuracy resolved in our vertical land motion dataset can transform the analysis of natural and anthropogenic changes in relative sea-level and associated hazards.

2019 ◽  
Vol 11 (3) ◽  
pp. 277 ◽  
Author(s):  
Suresh Palanisamy Vadivel ◽  
Duk-jin Kim ◽  
Jungkyo Jung ◽  
Yang-Ki Cho ◽  
Ki-Jong Han ◽  
...  

Vertical land motion at tide gauges influences sea level rise acceleration; this must be addressed for interpreting reliable sea level projections. In recent years, tide gauge records for the Eastern coast of Korea have revealed rapid increases in sea level rise compared with the global mean. Pohang Tide Gauge Station has shown a +3.1 cm/year sea level rise since 2013. This study aims to estimate the vertical land motion that influences relative sea level rise observations at Pohang by applying a multi-track Persistent Scatter Interferometric Synthetic Aperture Radar (PS-InSAR) time-series analysis to Sentinel-1 SAR data acquired during 2015–2017. The results, which were obtained at a high spatial resolution (10 m), indicate vertical ground motion of −2.55 cm/year at the Pohang Tide Gauge Station; this was validated by data from a collocated global positioning system (GPS) station. The subtraction of InSAR-derived subsidence rates from sea level rise at the Pohang Tide Gauge Station is 6 mm/year; thus, vertical land motion significantly dominates the sea level acceleration. Natural hazards related to the sea level rise are primarily assessed by relative sea level changes obtained from tide gauges; therefore, tide gauge records should be reviewed for rapid vertical land motion along the vulnerable coastal areas.


2020 ◽  
Author(s):  
Kristy Tiampo ◽  
Michael Willis ◽  
R. Steven Nerem ◽  
Heijkoop Eduard ◽  
Johnson Joel

<p>Today, the joint phenomena of rapid urbanization and population growth has resulted in an increase in the number of cities of over 10 million inhabitants, or megacities, worldwide.  While western megacities such as Los Angeles have been relatively stable in recent years, the developing world saw an increase from two to thirteen between 1975 and 2000 (http://www.igbp.net). In 2011, sixteen of the 23 global cities that fell into that category were coastal (UN-DESA 2012). Their growth is often coupled with unplanned urbanization and sprawl, with important effects on coastlines, demographics and ecosystems (Angel et al. 2011; Allison et al., 2016).  The associated risk is exacerbated by anthropogenic coastal subsidence processes and sea-level rise due to climate change, potentially increasing inundation, flooding, storm surges and infrastructure damage. Ground deformation phenomena, either uplift and/or subsidence, can arise from volcanic and tectonic processes, hydrocarbon exploitation, groundwater pumping and shallow compaction of sediments, particularly along coastal deltas. A better understanding of the processes affecting coastal megacities can be achieved through the combination of satellite and ground-based measurements.  Here we combine both high-resolution topography, in the form of optical digital surface models (DSMs), and differential interferometric synthetic aperture radar (DInSAR), to better characterize the effects of local and regional subsidence, coastal erosion, sea-level rise and urbanization in several megacities from around the developing world.   DInSAR time series from Sentinel-1A/B images, coregistered to high-resolution DSMs, are used to constrain local and regional ground deformation, while those same DSMs can be used to better model inundation due to sea level rise.  Here we present results for a number of cities, including but not limited to Mumbai, Lagos and Dhaka.</p>


2019 ◽  
Vol 176 ◽  
pp. 132-143 ◽  
Author(s):  
A. Martínez-Asensio ◽  
G. Wöppelmann ◽  
V. Ballu ◽  
M. Becker ◽  
L. Testut ◽  
...  

2021 ◽  
Author(s):  
Cheryl Tay ◽  
Eric Lindsey ◽  
Shi Tong Chin ◽  
Jamie McCaughey ◽  
David Bekaert ◽  
...  

Abstract Coastal land is being lost worldwide at an alarming rate due to relative sea-level rise (RSLR) resulting from vertical land motion (VLM). This problem is understudied at a global scale, due to high spatial variability and difficulties reconciling VLM between regions. Here we provide self-consistent, high spatial resolution VLM observations derived from Interferometric Synthetic Aperture Radar for the 51 largest coastal cities, representing 22% of the global urban population. We show that peak subsidence rates are faster than current global mean sea-level rise rates and VLM contributions to RSLR are greater than IPCC projections in 90% and 53% of the cities respectively. Localized VLM worsens RSLR impacts on land and population in 73-75% of the cities, with Chittagong (Bangladesh), Yangon (Myanmar) and Jakarta (Indonesia) at greatest risk. With this dataset, accurate projections and comparisons of RSLR effects accounting for VLM are now possible for urban areas at a global scale.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
T. C. Harvey ◽  
B. D. Hamlington ◽  
T. Frederikse ◽  
R. S. Nerem ◽  
C. G. Piecuch ◽  
...  

AbstractRegional sea-level changes are caused by several physical processes that vary both in space and time. As a result of these processes, large regional departures from the long-term rate of global mean sea-level rise can occur. Identifying and understanding these processes at particular locations is the first step toward generating reliable projections and assisting in improved decision making. Here we quantify to what degree contemporary ocean mass change, sterodynamic effects, and vertical land motion influence sea-level rise observed by tide-gauge locations around the contiguous U.S. from 1993 to 2018. We are able to explain tide gauge-observed relative sea-level trends at 47 of 55 sampled locations. Locations where we cannot explain observed trends are potentially indicative of shortcomings in our coastal sea-level observational network or estimates of uncertainty.


2017 ◽  
Vol 18 (5) ◽  
pp. 1343-1355
Author(s):  
Michelle A. Hummel ◽  
Nathan J. Wood ◽  
Amy Schweikert ◽  
Mark T. Stacey ◽  
Jeanne Jones ◽  
...  

2021 ◽  
Vol 118 (29) ◽  
pp. e2025961118
Author(s):  
Michelle A. Hummel ◽  
Robert Griffin ◽  
Katie Arkema ◽  
Anne D. Guerry

Coastal communities rely on levees and seawalls as critical protection against sea-level rise; in the United States alone, $300 billion in shoreline armoring costs are forecast by 2100. However, despite the local flood risk reduction benefits, these structures can exacerbate flooding and associated damages along other parts of the shoreline—particularly in coastal bays and estuaries, where nearly 500 million people globally are at risk from sea-level rise. The magnitude and spatial distribution of the economic impact of this dynamic, however, are poorly understood. Here we combine hydrodynamic and economic models to assess the extent of both local and regional flooding and damages expected from a range of shoreline protection and sea-level rise scenarios in San Francisco Bay, California. We find that protection of individual shoreline segments (5 to 75 km) can increase flooding in other areas by as much as 36 million m3 and damages by $723 million for a single flood event and in some cases can even cause regional flood damages that exceed the local damages prevented from protection. We also demonstrate that strategic flooding of certain shoreline segments, such as those with gradually sloping baylands and space for water storage, can help alleviate flooding and damages along other stretches of the coastline. By matching the scale of the economic assessment to the scale of the threat, we reveal the previously uncounted costs associated with uncoordinated adaptation actions and demonstrate that a regional planning perspective is essential for reducing shared risk and wisely spending adaptation resources in coastal bays.


2020 ◽  
Vol 644 ◽  
pp. 33-45
Author(s):  
JM Hill ◽  
PS Petraitis ◽  
KL Heck

Salt marshes face chronic anthropogenic impacts such as relative sea level rise and eutrophication, as well as acute disturbances from tropical storms that can affect the productivity of these important communities. However, it is not well understood how marshes already subjected to eutrophication and sea level rise will respond to added effects of episodic storms such as hurricanes. We examined the interactive effects of nutrient addition, sea level rise, and a hurricane on the growth, biomass accumulation, and resilience of the saltmarsh cordgrass Spartina alterniflora in the Gulf of Mexico. In a microtidal marsh, we manipulated nutrient levels and submergence using marsh organs in which cordgrasses were planted at differing intertidal elevations and measured the impacts of Hurricane Isaac, which occurred during the experiment. Prior to the hurricane, grasses at intermediate and high elevations increased in abundance. After the hurricane, all treatments lost approximately 50% of their shoots, demonstrating that added nutrients and elevation did not provide resistance to hurricane disturbance. At the end of the experiment, only the highest elevations had been resilient to the hurricane, with increased above- and belowground growth. Added nutrients provided a modest increase in above- and belowground growth, but only at the highest elevations, suggesting that only elevation will enhance resilience to hurricane disturbance. These results empirically demonstrate that S. alterniflora in microtidal locations already subjected to submergence stress is less able to recover from storm disturbance and suggests we may be underestimating the loss of northern Gulf Coast marshes due to relative sea level rise.


Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1142
Author(s):  
Juliano Calil ◽  
Geraldine Fauville ◽  
Anna Carolina Muller Queiroz ◽  
Kelly L. Leo ◽  
Alyssa G. Newton Mann ◽  
...  

As coastal communities around the globe contend with the impacts of climate change including coastal hazards such as sea level rise and more frequent coastal storms, educating stakeholders and the general public has become essential in order to adapt to and mitigate these risks. Communicating SLR and other coastal risks is not a simple task. First, SLR is a phenomenon that is abstract as it is physically distant from many people; second, the rise of the sea is a slow and temporally distant process which makes this issue psychologically distant from our everyday life. Virtual reality (VR) simulations may offer a way to overcome some of these challenges, enabling users to learn key principles related to climate change and coastal risks in an immersive, interactive, and safe learning environment. This article first presents the literature on environmental issues communication and engagement; second, it introduces VR technology evolution and expands the discussion on VR application for environmental literacy. We then provide an account of how three coastal communities have used VR experiences developed by multidisciplinary teams—including residents—to support communication and community outreach focused on SLR and discuss their implications.


Terra Nova ◽  
1992 ◽  
Vol 4 (3) ◽  
pp. 293-304 ◽  
Author(s):  
J.C. Varekamp ◽  
E. Thomas ◽  
O. Plassche

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