scholarly journals Feedbacks and mechanisms affecting the global sensitivity of glaciers to climate change

2014 ◽  
Vol 8 (1) ◽  
pp. 59-71 ◽  
Author(s):  
B. Marzeion ◽  
A. H. Jarosch ◽  
J. M. Gregory

Abstract. Mass loss by glaciers has been an important contributor to sea level rise in the past, and is projected to contribute a substantial fraction of total sea level rise during the 21st century. Here, we use a model of the world's glaciers to quantify equilibrium sensitivities of global glacier mass to climate change, and to investigate the role of changes in glacier hypsometry for long-term mass changes. We find that 21st century glacier-mass loss is largely governed by the glacier's response to 20th century climate change. This limits the influence of 21st century climate change on glacier-mass loss, and explains why there are relatively small differences in glacier-mass loss under greatly different scenarios of climate change. The projected future changes in both temperature and precipitation experienced by glaciers are amplified relative to the global average. The projected increase in precipitation partly compensates for the mass loss caused by warming, but this compensation is negligible at higher temperature anomalies since an increasing fraction of precipitation at the glacier sites is liquid. Loss of low-lying glacier area, and more importantly, eventual complete disappearance of glaciers, strongly limit the projected sea level contribution from glaciers in coming centuries. The adjustment of glacier hypsometry to changes in the forcing strongly reduces the rates of global glacier-mass loss caused by changes in global mean temperature compared to rates of mass loss when hypsometric changes are neglected. This result is a second reason for the relatively weak dependence of glacier-mass loss on future climate scenario, and helps explain why glacier-mass loss in the first half of the 20th century was of the same order of magnitude as in the second half of the 20th century, even though the rate of warming was considerably smaller.

2013 ◽  
Vol 7 (3) ◽  
pp. 2761-2800 ◽  
Author(s):  
B. Marzeion ◽  
A. H. Jarosch ◽  
J. M. Gregory

Abstract. Mass loss by glaciers has been an important contributor to sea level rise in the past and is projected to contribute a substantial fraction of total sea level rise during the 21st century. Here, we use a model of the world's glaciers in order to quantify equilibrium sensitivities of global glacier mass to climate change, and to investigate the role of changes in glacier hypsometry for long term mass changes. We find that 21st century glacier mass loss to a~large degree is governed by the glaciers responding to 20th century climate change. This limits the influence of 21st century climate change on glacier mass loss, and explains why there are relatively small differences in glacier mass loss under greatly different scenarios of climate change. Because of the geographic distribution of glaciers, both temperature and precipitation anomalies experienced by glaciers are vastly stronger than on global average. The projected increase in precipitation partly compensates for the mass loss caused by warming, but this compensation is negligible at higher temperature anomalies since an increasing fraction of precipitation at the glacier sites it liquid. Loss of low-lying glacier area, and more importantly, eventual complete disappearance of glaciers, strongly limit the projected sea level contribution from glaciers in coming centuries. The adjustment of glacier hypsometry to changes in the forcing reduces the sensitivity of global glacier mass to changes in global mean temperature by a factor of two to three. This result is a second reason for the relatively weak dependence of glacier mass loss on future climate scenario, and helps explain why glacier mass loss in the first half of the 20th century was of the same order of magnitude as in the second half of the 20th century, even though the rate of warming was considerably smaller.


2018 ◽  
Vol 97 (3) ◽  
pp. 79-127 ◽  
Author(s):  
Bert L.A. Vermeersen ◽  
Aimée B.A. Slangen ◽  
Theo Gerkema ◽  
Fedor Baart ◽  
Kim M. Cohen ◽  
...  

AbstractRising sea levels due to climate change can have severe consequences for coastal populations and ecosystems all around the world. Understanding and projecting sea-level rise is especially important for low-lying countries such as the Netherlands. It is of specific interest for vulnerable ecological and morphodynamic regions, such as the Wadden Sea UNESCO World Heritage region.Here we provide an overview of sea-level projections for the 21st century for the Wadden Sea region and a condensed review of the scientific data, understanding and uncertainties underpinning the projections. The sea-level projections are formulated in the framework of the geological history of the Wadden Sea region and are based on the regional sea-level projections published in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). These IPCC AR5 projections are compared against updates derived from more recent literature and evaluated for the Wadden Sea region. The projections are further put into perspective by including interannual variability based on long-term tide-gauge records from observing stations at Den Helder and Delfzijl.We consider three climate scenarios, following the Representative Concentration Pathways (RCPs), as defined in IPCC AR5: the RCP2.6 scenario assumes that greenhouse gas (GHG) emissions decline after 2020; the RCP4.5 scenario assumes that GHG emissions peak at 2040 and decline thereafter; and the RCP8.5 scenario represents a continued rise of GHG emissions throughout the 21st century. For RCP8.5, we also evaluate several scenarios from recent literature where the mass loss in Antarctica accelerates at rates exceeding those presented in IPCC AR5.For the Dutch Wadden Sea, the IPCC AR5-based projected sea-level rise is 0.07±0.06m for the RCP4.5 scenario for the period 2018–30 (uncertainties representing 5–95%), with the RCP2.6 and RCP8.5 scenarios projecting 0.01m less and more, respectively. The projected rates of sea-level change in 2030 range between 2.6mma−1for the 5th percentile of the RCP2.6 scenario to 9.1mma−1for the 95th percentile of the RCP8.5 scenario. For the period 2018–50, the differences between the scenarios increase, with projected changes of 0.16±0.12m for RCP2.6, 0.19±0.11m for RCP4.5 and 0.23±0.12m for RCP8.5. The accompanying rates of change range between 2.3 and 12.4mma−1in 2050. The differences between the scenarios amplify for the 2018–2100 period, with projected total changes of 0.41±0.25m for RCP2.6, 0.52±0.27m for RCP4.5 and 0.76±0.36m for RCP8.5. The projections for the RCP8.5 scenario are larger than the high-end projections presented in the 2008 Delta Commission Report (0.74m for 1990–2100) when the differences in time period are considered. The sea-level change rates range from 2.2 to 18.3mma−1for the year 2100.We also assess the effect of accelerated ice mass loss on the sea-level projections under the RCP8.5 scenario, as recent literature suggests that there may be a larger contribution from Antarctica than presented in IPCC AR5 (potentially exceeding 1m in 2100). Changes in episodic extreme events, such as storm surges, and periodic (tidal) contributions on (sub-)daily timescales, have not been included in these sea-level projections. However, the potential impacts of these processes on sea-level change rates have been assessed in the report.


2012 ◽  
Vol 1 (33) ◽  
pp. 19 ◽  
Author(s):  
Sayaka Hoshino ◽  
Miguel Esteban ◽  
Takahito Mikami ◽  
Tomoyuki Takabatake ◽  
Tomoya Shibayama

Sea level rise and an increase in typhoon intensity are two of the expected consequences from future climate change. In the present work a methodology to change the intensity of tropical cyclones in Japan was developed, which can be used to assess the inundation risk to different areas of the country. An example of how this would affect one of the worst typhoons to hit the Tokyo Bay area in the 20th century was thus developed, highlighting the considerable dangers associated with this event, and how current sea defences could be under danger of failing by the end of the 21st century.


2020 ◽  
Vol 12 (9) ◽  
pp. 3737
Author(s):  
Osamu Nishiura ◽  
Makoto Tamura ◽  
Shinichiro Fujimori ◽  
Kiyoshi Takahashi ◽  
Junya Takakura ◽  
...  

Coastal areas provide important services and functions for social and economic activities. Damage due to sea level rise (SLR) is one of the serious problems anticipated and caused by climate change. In this study, we assess the global economic impact of inundation due to SLR by using a computable general equilibrium (CGE) model that incorporates detailed coastal damage information. The scenario analysis considers multiple general circulation models, socioeconomic assumptions, and stringency of climate change mitigation measures. We found that the global household consumption loss proportion will be 0.045%, with a range of 0.027−0.066%, in 2100. Socioeconomic assumptions cause a difference in the loss proportion of up to 0.035% without greenhouse gas (GHG) emissions mitigation, the so-called baseline scenarios. The range of the loss proportion among GHG emission scenarios is smaller than the differences among the socioeconomic assumptions. We also observed large regional variations and, in particular, the consumption losses in low-income countries are, relatively speaking, larger than those in high-income countries. These results indicate that, even if we succeed in stabilizing the global mean temperature increase below 2 °C, economic losses caused by SLR will inevitably happen to some extent, which may imply that keeping the global mean temperature increase below 1.5 °C would be worthwhile to consider.


2020 ◽  
Author(s):  
Pau Luque Lozano ◽  
Lluís Gómez-Pujol ◽  
Marta Marcos ◽  
Alejandro Orfila

<p>Sea-level rise induces a permanent loss of land with widespread ecological and economic impacts, most evident in urban and densely populated areas. The eventual coastline retreat combined with the action of waves and storm surges will end in more severe damages over coastal areas. These effects are expected to be particularly significant over islands, where coastal zones represent a relatively larger area vulnerable to marine hazards.</p><p>Managing coastal flood risk at regional scales requires a prioritization of resources and socioeconomic activities along the coast. Stakeholders, such as regional authorities, coastal managers and private companies, need tools that help to address the evaluation of coastal risks and criteria to support decision-makers to clarify priorities and critical sites. For this reason, the regional Government of the Balearic Islands (Spain) in association with the Spanish Ministry of Agriculture, Fisheries and Environment has launched the Plan for Climate Change Coastal Adaptation. This framework integrates two levels of analysis. The first one relates with the identification of critical areas affected by coastal flooding and erosion under mean sea-level rise scenarios and the quantification of the extent of flooding, including marine extreme events. The second level assesses the impacts on infrastructures and assets from a socioeconomic perspective due to these hazards.</p><p>In this context, this paper quantifies the effects of sea-level rise and marine extreme events caused by storm surges and waves along the coasts of the Balearic Islands (Western Mediterranean Sea) in terms of coastal flooding and potential erosion. Given the regional scale (~1500 km) of this study, the presented methodology adopts a compromise between accuracy, physical representativity and computational costs. We map the projected flooded coastal areas under two mean sea-level rise climate change scenarios, RCP4.5 and RCP8.5. To do so, we apply a corrected bathtub algorithm. Additionally, we compute the impact of extreme storm surges and waves using two 35-year hindcasts consistently forced by mean sea level pressure and surface winds from ERA-Interim reanalysis. Waves have been further propagated towards the nearshore to compute wave setup with higher accuracy. The 100-year return levels of joint storm surges and waves are used to map the spatial extent of flooding in more than 200 sandy beaches around the Balearic Islands by mid and late 21st century, using the hydrodynamical LISFLOOD-FP model and a high resolution (2 m) Digital Elevation Model.</p>


2017 ◽  

The effects of climate change have been observed on agricultural lands in the Caribbean. Climate change effects include shifts in temperature and precipitation, which can manifest as water scarcity or excess, above normal temperatures, sea level rise, as well as frequent tropical storms.


2015 ◽  
Vol 9 (5) ◽  
pp. 4865-4892
Author(s):  
I. S. Muresan ◽  
S. A. Khan ◽  
A. Aschwanden ◽  
C. Khroulev ◽  
T. Van Dam ◽  
...  

Abstract. Observations over the past two decades show substantial ice loss associated with the speedup of marine terminating glaciers in Greenland. Here we use a regional 3-D outlet glacier model to simulate the behaviour of Jakobshavn Isbræ (JI) located in west Greenland. Using atmospheric and oceanic forcing we tune our model to reproduce the observed frontal changes of JI during 1990–2014. We identify two major accelerations. The first occurs in 1998, and is triggered by moderate thinning prior to 1998. The second acceleration, which starts in 2003 and peaks in summer 2004, is triggered by the final breakup of the floating tongue, which generates a reduction in buttressing at the JI terminus. This results in further thinning, and as the slope steepens inland, sustained high velocities have been observed at JI over the last decade. As opposed to other regions on the Greenland Ice Sheet (GrIS), where dynamically induced mass loss has slowed down over recent years, both modelled and observed results for JI suggest a continuation of the acceleration in mass loss. Further, we find that our model is not able to capture the 2012 peak in the observed velocities. Our analysis suggests that the 2012 acceleration of JI is likely the result of an exceptionally long melt season dominated by extreme melt events. Considering that such extreme surface melt events are expected to intensify in the future, our findings suggest that the 21st century projections of the GrIS mass loss and the future sea level rise may be larger than predicted by existing modelling results.


1969 ◽  
Vol 31 ◽  
pp. 87-90
Author(s):  
Morten L. Andersen ◽  
Signe B. Andersen ◽  
Lars Stenseng ◽  
Henriette Skourup ◽  
William Colgan ◽  
...  

The Greenland ice sheet is losing mass to the ocean at an increasing rate (Thomas et al. 2006). During the 1980s the ice sheet was believed to be in near-equilibrium (van den Broeke et al. 2009). Within the first decade of the 21st century, however, a net negative balance was observed. Greenland’s present rate of ice loss is c. 250 Gt yr–1, equivalent to a sea-level rise contribution of c. 0.69 mm yr–1. The rate of ice loss has increased over the post 1992 observation period (Shepherd et al. 2012).


2015 ◽  
Vol 17 (7) ◽  
pp. 1311-1322 ◽  
Author(s):  
S. Kay ◽  
J. Caesar ◽  
J. Wolf ◽  
L. Bricheno ◽  
R. J. Nicholls ◽  
...  

A hydrodynamic model of the Bay of Bengal has been used to explore increasing frequency of extreme sea levels in the Ganges–Brahmaputra–Meghna delta over the 21st century.


2018 ◽  
Vol 9 (4) ◽  
pp. 1169-1189 ◽  
Author(s):  
Martin Rückamp ◽  
Ulrike Falk ◽  
Katja Frieler ◽  
Stefan Lange ◽  
Angelika Humbert

Abstract. Sea-level rise associated with changing climate is expected to pose a major challenge for societies. Based on the efforts of COP21 to limit global warming to 2.0 ∘C or even 1.5 ∘C by the end of the 21st century (Paris Agreement), we simulate the future contribution of the Greenland ice sheet (GrIS) to sea-level change under the low emission Representative Concentration Pathway (RCP) 2.6 scenario. The Ice Sheet System Model (ISSM) with higher-order approximation is used and initialized with a hybrid approach of spin-up and data assimilation. For three general circulation models (GCMs: HadGEM2-ES, IPSL-CM5A-LR, MIROC5) the projections are conducted up to 2300 with forcing fields for surface mass balance (SMB) and ice surface temperature (Ts) computed by the surface energy balance model of intermediate complexity (SEMIC). The projected sea-level rise ranges between 21–38 mm by 2100 and 36–85 mm by 2300. According to the three GCMs used, global warming will exceed 1.5 ∘C early in the 21st century. The RCP2.6 peak and decline scenario is therefore manually adjusted in another set of experiments to suppress the 1.5 ∘C overshooting effect. These scenarios show a sea-level contribution that is on average about 38 % and 31 % less by 2100 and 2300, respectively. For some experiments, the rate of mass loss in the 23rd century does not exclude a stable ice sheet in the future. This is due to a spatially integrated SMB that remains positive and reaches values similar to the present day in the latter half of the simulation period. Although the mean SMB is reduced in the warmer climate, a future steady-state ice sheet with lower surface elevation and hence volume might be possible. Our results indicate that uncertainties in the projections stem from the underlying GCM climate data used to calculate the surface mass balance. However, the RCP2.6 scenario will lead to significant changes in the GrIS, including elevation changes of up to 100 m. The sea-level contribution estimated in this study may serve as a lower bound for the RCP2.6 scenario, as the currently observed sea-level rise is not reached in any of the experiments; this is attributed to processes (e.g. ocean forcing) not yet represented by the model, but proven to play a major role in GrIS mass loss.


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