Assessing the Impacts of Global Sea Level Rise (SLR) on the Mangrove Forests of Indian Sundarbans Using Geospatial Technology

The Indian Sundarbans, together with Bangladesh, comprise the largest mangrove forest in the world. Reclamation of the mangroves in this region ceased in the 1930s. However, they are still subject to adverse environmental influences, such as sediment starvation due to migration of the main river channels in the Ganges–Brahmaputra delta over the last few centuries, cyclone landfall, wave action from the Bay of Bengal—changing hydrology due to upstream water diversion—and the pervasive effects of relative sea-level rise. This study builds on earlier work to assess changes from 2000 to 2020 in mangrove extent, genus composition, and mangrove ‘health’ indicators, using various vegetation indices derived from Landsat and MODIS satellite imagery by performing maximum likelihood supervised classification. We show that about 110 km2 of mangroves disappeared within the reserve forest due to erosion, and 81 km2 were gained within the inhabited part of Sundarbans Biosphere Reserve (SBR) through plantation and regeneration. The gains are all outside the contiguous mangroves. However, they partially compensate for the losses of the contiguous mangroves in terms of carbon. Genus composition, analyzed by amalgamating data from published literature and ground-truthing surveys, shows change towards more salt-tolerant genus accompanied by a reduction in the prevalence of freshwater-loving Heiritiera, Nypa, and Sonneratia assemblages. Health indicators, such as the enhanced vegetation index (EVI) and normalized differential vegetation index (NDVI), show a monotonic trend of deterioration over the last two decades, which is more pronounced in the sea-facing parts of the mangrove forests. An increase in salinity, a temperature rise, and rainfall reduction in the pre-monsoon and the post-monsoon periods appear to have led to such degradation. Collectively, these results show a decline in mangrove area and health, which poses an existential threat to the Indian Sundarbans in the long term, especially under scenarios of climate change and sea-level rise. Given its unique values, the policy process should acknowledge and address these threats.

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Sedimentation and soil carbon accumulation in degraded mangrove forests of North Sumatra, Indonesia

10.1101/325191 ◽

2018 ◽

Author(s):

Daniel Murdiyarso ◽

Bayu Budi Hanggara ◽

Ali Arman Lubis

Keyword(s):

Soil Carbon ◽

Sea Level Rise ◽

Sea Level ◽

Atomic Bomb ◽

Carbon Accumulation ◽

Tidal Range ◽

Mangrove Forests ◽

Geological Formation ◽

Soil Carbon Accumulation ◽

Global Sea Level

AbstractMangrove ecosystems are often referred to as “land builders” because of their ability to trap sediments transported from the uplands as well as from the oceans. The sedimentation process in mangrove areas is influenced by hydro-geomorphic settings that represent the tidal range and coastal geological formation. We estimated the sedimentation rate in North Sumatran mangrove forests using the 210Pb radionuclide technique, also known as the constant rate supply method, and found that mudflats, fringes, and interior mangroves accreted 4.3 ± 0.2 mm yr−1, 5.6 ± 0.3 mm yr1, and 3.7 ± 0.2 mm yr−1, respectively. Depending on the subsurface changes, these rates could potentially keep pace with global sea level rise of 2.6−3.2 mm yr−1, except the interior mangrove they would also be able to cope with regional sea-level rise of 4.2 ± 0.4 mm yr−1. The mean soil carbon accumulation rates in the mudflats, fringes, and interior areas were 40.1 ± 6.9 g C m−2yr−1, 50.1 ± 8.8 g C m−2yr−1, and 47.7 ± 12.5 g C m−2yr−1, respectively, much lower than the published global average of 226 ± 39 g C m−2yr−1. We also found that based on the excess of radioactive elements derived from atomic bomb fallout, the sediment in the mudflat area was deposited since over 28 years ago, and is much younger than the sediment deposited in the interior and fringe areas that are 43 years 54 years old, respectively.

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Analysis of the Makran Coastline of Iran’s Vulnerability to Global Sea-Level Rise

Journal of Marine Science and Engineering ◽

10.3390/jmse9080891 ◽

2021 ◽

Vol 9 (8) ◽

pp. 891

Author(s):

Ezatollah Ghanavati ◽

Majid Shah-Hosseini ◽

Nick Marriner

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Global Climate ◽

Shoreline Change ◽

Vulnerability Index ◽

Sandy Beaches ◽

Tidal Range ◽

Rocky Shores ◽

Mangrove Forests ◽

Global Sea Level

The SE coast of Iran is of great economic and environmental importance. Global climate change affects this coastline through sea level rise (SLR), compounded by a decrease in sediment budgets in coastal areas. This study developed a Coastal Vulnerability Index (CVI) for the SE coast of Iran using satellite, instrumental and field data. Eight risk variables were defined: coastal slope, regional coastal elevation, mean tidal range, mean significant wave height, rate of relative sea-level change, rate of shoreline change, environmental sensitivity and socio-economic sensitivity. The coast was divided into 27 segments based on geomorphic, environmental and socioeconomic traits. Coastal segments were categorized based on their vulnerability to each risk factor using a CVI. The resulting maps highlighted the vulnerability of each coastal segment to SLR. Approximately 50% of the coast is comprised of mostly rocky shores, which are less vulnerable to SLR. Approximately 33% of the coastal length, including sandy beaches, tidal flats and mangrove forests, were determined to be highly vulnerable to SLR. Approximately 12% of the coastline was determined to be moderately vulnerable. Population centers and infrastructure were ranked as highly-to-moderately vulnerable to SLR. This study highlighted the high vulnerability of low-lying areas, such as lagoons and mangroves, in the western part of the Iranian coast of Makran. Proper coastal management and mitigation plans are essential in the future to protect coastal societies and environments.

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Reply to ‘Waves do not contribute to global sea-level rise’

Nature Climate Change ◽

10.1038/s41558-018-0378-4 ◽

2018 ◽

Vol 9 (1) ◽

pp. 3-3 ◽

Cited By ~ 3

Author(s):

Angélique Melet ◽

Benoît Meyssignac ◽

Rafaël Almar ◽

Gonéri Le Cozannet

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Global Sea Level

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A Macro-project to Reduce Hurricane Intensity and slow Global Sea Level Rise

Macro-Engineering - Water Science and Technology Library ◽

10.1007/1-4020-4604-9_5 ◽

2007 ◽

pp. 53-63 ◽

Cited By ~ 1

Author(s):

Richard LaRosa

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Hurricane Intensity ◽

Global Sea Level

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Greenland ice sheet contribution to sea level rise during the last interglacial period: a modelling study driven and constrained by ice core data

Climate of the Past ◽

10.5194/cp-9-353-2013 ◽

2013 ◽

Vol 9 (1) ◽

pp. 353-366 ◽

Cited By ~ 42

Author(s):

A. Quiquet ◽

C. Ritz ◽

H. J. Punge ◽

D. Salas y Mélia

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Ice Core ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Interglacial Period ◽

Last Interglacial ◽

Intergovernmental Panel ◽

Orbital Configuration ◽

Global Sea Level

Abstract. As pointed out by the forth assessment report of the Intergovernmental Panel on Climate Change, IPCC-AR4 (Meehl et al., 2007), the contribution of the two major ice sheets, Antarctica and Greenland, to global sea level rise, is a subject of key importance for the scientific community. By the end of the next century, a 3–5 °C warming is expected in Greenland. Similar temperatures in this region were reached during the last interglacial (LIG) period, 130–115 ka BP, due to a change in orbital configuration rather than to an anthropogenic forcing. Ice core evidence suggests that the Greenland ice sheet (GIS) survived this warm period, but great uncertainties remain about the total Greenland ice reduction during the LIG. Here we perform long-term simulations of the GIS using an improved ice sheet model. Both the methodologies chosen to reconstruct palaeoclimate and to calibrate the model are strongly based on proxy data. We suggest a relatively low contribution to LIG sea level rise from Greenland melting, ranging from 0.7 to 1.5 m of sea level equivalent, contrasting with previous studies. Our results suggest an important contribution of the Antarctic ice sheet to the LIG highstand.

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Greenland ice sheet hydrology

Progress in Physical Geography Earth and Environment ◽

10.1177/0309133313507075 ◽

2013 ◽

Vol 38 (1) ◽

pp. 19-54 ◽

Cited By ~ 85

Author(s):

Vena W. Chu

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Field Studies ◽

Ice Dynamics ◽

Surface Water Hydrology ◽

Basal Sliding ◽

Hydrologic System ◽

Global Sea Level

Understanding Greenland ice sheet (GrIS) hydrology is essential for evaluating response of ice dynamics to a warming climate and future contributions to global sea level rise. Recently observed increases in temperature and melt extent over the GrIS have prompted numerous remote sensing, modeling, and field studies gauging the response of the ice sheet and outlet glaciers to increasing meltwater input, providing a quickly growing body of literature describing seasonal and annual development of the GrIS hydrologic system. This system is characterized by supraglacial streams and lakes that drain through moulins, providing an influx of meltwater into englacial and subglacial environments that increases basal sliding speeds of outlet glaciers in the short term. However, englacial and subglacial drainage systems may adjust to efficiently drain increased meltwater without significant changes to ice dynamics over seasonal and annual scales. Both proglacial rivers originating from land-terminating glaciers and subglacial conduits under marine-terminating glaciers represent direct meltwater outputs in the form of fjord sediment plumes, visible in remotely sensed imagery. This review provides the current state of knowledge on GrIS surface water hydrology, following ice sheet surface meltwater production and transport via supra-, en-, sub-, and proglacial processes to final meltwater export to the ocean. With continued efforts targeting both process-level and systems analysis of the hydrologic system, the larger picture of how future changes in Greenland hydrology will affect ice sheet glacier dynamics and ultimately global sea level rise can be advanced.

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Decadal-scale onset and termination of Antarctic ice-mass loss during the last deglaciation

Nature Communications ◽

10.1038/s41467-021-27053-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Michael E. Weber ◽

Nicholas R. Golledge ◽

Chris J. Fogwill ◽

Chris S. M. Turney ◽

Zoë A. Thomas

Keyword(s):

Mass Loss ◽

Sea Level Rise ◽

Sea Level ◽

Ross Sea ◽

Ice Sheet ◽

Rate Of Change ◽

Last Deglaciation ◽

Decadal Scale ◽

Ice Sheet Modeling ◽

Global Sea Level

AbstractEmerging ice-sheet modeling suggests once initiated, retreat of the Antarctic Ice Sheet (AIS) can continue for centuries. Unfortunately, the short observational record cannot resolve the tipping points, rate of change, and timescale of responses. Iceberg-rafted debris data from Iceberg Alley identify eight retreat phases after the Last Glacial Maximum that each destabilized the AIS within a decade, contributing to global sea-level rise for centuries to a millennium, which subsequently re-stabilized equally rapidly. This dynamic response of the AIS is supported by (i) a West Antarctic blue ice record of ice-elevation drawdown >600 m during three such retreat events related to globally recognized deglacial meltwater pulses, (ii) step-wise retreat up to 400 km across the Ross Sea shelf, (iii) independent ice sheet modeling, and (iv) tipping point analysis. Our findings are consistent with a growing body of evidence suggesting the recent acceleration of AIS mass loss may mark the beginning of a prolonged period of ice sheet retreat and substantial global sea level rise.

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Rising Sea Level, Receding Boundaries and Freezing Baselines in a Warming Climate

Current Journal of Applied Science and Technology ◽

10.9734/cjast/2019/v36i630260 ◽

2019 ◽

pp. 1-7

Author(s):

Emojong Amai Mercy ◽

Eliud Garry Michura

Keyword(s):

Climate Change ◽

Sea Level Rise ◽

Sea Level ◽

Future Climate Change ◽

Maritime Boundary ◽

Climate Change Effect ◽

Global Sea Level ◽

Comprehensive Framework ◽

Maritime Boundary Delimitation ◽

International Boundaries

This paper discusses the less publicised but far from less significant, an issue of how the international community’s approach to maritime boundary delimitation will be impacted by climate change resulting in sea level rise with coastal lands submerging affecting the international boundaries and impacting on biodiversity and human survival in the future. The climate change effect is already creating pressure on international law regardless of the direction that the law of the sea takes in remedying this dilemma. It is quite apparent that global disputes and conflicts are arising and solutions are needed urgently. The climate change and the consequent global sea level rise are widely touted to submerge islands and coastlines without discrimination. The international community has been relatively slow to react to what could pose an unprecedented threat to human civilisation. The policies that have been applied have arguably been reactive and not proactive. In future climate change may develop other by-products which may not be understood at this moment and may require a proactive approach. Further discussion of the merits of the potential paths is ideal in ensuring that appropriate and well thought-out resolutions are negotiated. Regardless of the outcome, the thorough debate is required to ensure the correct decision is made and that the balancing act between fulfilling states' interests and achieving a meaningful result does not become detrimental to the solidity and the enforceability of the outcome. There is a need to establish a comprehensive framework for ocean governance for management and long-term development and sustainability.

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Fossil shorelines at Corfu and surrounding islands deduced from erosional notches

The Holocene ◽

10.1177/0959683614544057 ◽

2014 ◽

Vol 24 (11) ◽

pp. 1565-1572 ◽

Cited By ~ 5

Author(s):

Niki Evelpidou ◽

Anna Karkani ◽

Paolo A Pirazzoli

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Vertical Movements ◽

Northeastern Part ◽

Vertical Displacements ◽

Global Sea Level ◽

Tectonic Movements

New geomorphological investigations along the coasts of Corfu, Othonoi, Paxoi, and Antipaxoi Islands allowed the identification of recent fossil shorelines. Former sea-level positions were deduced from sea-level indicators. A ‘modern’ tidal notch, submerged c. −20 cm, was observed in all studied islands. This notch is regarded to have been submerged by the global sea-level rise that occurred during the 19th and 20th centuries at a rate exceeding the possibilities of intertidal bioerosion. Its presence provides evidence that no vertical tectonic movements occurred since its formation. On Corfu, impacts of ancient earthquakes have left some marks of emergence at about ≥+130 ± 11, +110 ± 11, +65 ± 11, +40 ± 11, and +25 ± 11 cm, as well as marks of submergence at about −40 to −50, −85 ± 11, −120 ± 11, and −180 ± 11 cm. The emergence of +130 ± 11 cm, previously dated at about 790–400 cal. bc, was detected through erosion notches at various sites in the western part of Corfu and appears to continue even more west, at Othonoi Island. Tidal notches submerged at depths exceeding 0.4 m were observed in the northeastern part of the island and suggest the local occurrence of a sequence of four coseismic subsidences, with average vertical displacements of 40 cm, during at least the last few millennia. At Paxoi and Antipaxoi, Holocene vertical movements seem to have been mainly of subsidence. At Paxoi, the ‘modern’ notch was found at about −20 to −30 cm, while four more submerged tidal notches were distinguished at about −40 ± 11, −60 ± 11, −75 ± 11, and −90 ± 11 cm, while in Antipaxoi, three submerged tidal notches were distinguished at about −60 ± 11, −75 ± 11, and −120 ± 11 cm.

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