scholarly journals Symptoms and Driving Factors of Contemporary Earth Warming and Projections for the Future

2016 ◽  
Vol 23 (1) ◽  
pp. 37-57 ◽  
Author(s):  
Joanna Wibig

Abstract This paper outlines the symptoms of contemporary global warming, reviews its possible driving factors and presents some projections for future. Key among the symptoms are those related to temperature, with the increase in average global temperature since 1880 now reaching a value of 0.85°C. While warming has encompassed almost the whole world, the high latitudes have warmed more than the low, and maximum temperature has increased more than average temperature. Warming has been causing sea level rise, thanks to both the thermal expansion of warming water and the melting of ice on land. The other consequence of warming is a change in precipitation pattern, manifesting itself in higher precipitation in certain parts of the world (generally at low and high latitudes), but also lower precipitation in other parts (mainly the Tropics); as well as in changes in the intraannual course characterising precipitation (with more falling in winter and less in summer), and in the frequency and intensity of rainfall (more intense heavy-precipitation events and higher variability where the frequency of precipitation is concerned). Among the possible driving factors, the most important are those related to the increase of CO2 and mixing ratios of other greenhouse gases in the troposphere. Land-use changes and emissions of aerosols to the atmosphere also exert a major impact on temperature. These are mainly anthropogenic factors. While natural drivers also modulate the climate markedly, they tend to warm and cool the globe alternately, stepping up warming when they are in a warming phase, but slowing down or even offsetting warming during a cooling phase. Projections for the future are entirely dependent on socio-economic scenarios of future development. All the (economically) realistic scenarios point to a continuation of the warming trend, with a further intense sea-level rise and precipitation changes, albeit with the rate of change varying in line with the rate of increase in concentrations of the greenhouse gases. The realistic range of values for average rise in global temperature is between 2 and even 6 degrees Celsius.

2021 ◽  
Author(s):  
Christian Ferrarin ◽  
Piero Lionello ◽  
Mirko Orlic ◽  
Fabio Raicich ◽  
Gianfausto Salvadori

<p><span><span>Extreme sea levels at the coast result from the combination of astronomical tides with atmospherically forced fluctuations at multiple time scales. Seiches, river floods, waves, inter-annual and inter-decad</span></span><span><span>al dynamics and relative sea-level rise can also contribute to the total sea level. While tides are usually well described and predicted, the effect of the different atmospheric contributions to the sea level and their trends are still not well understood. Meso-scale atmospheric disturbances, synoptic-scale phenomena and planetary atmospheric waves (PAW) act at different temporal and spatial scales and thus generate sea-level disturbances at different frequencies. In this study, we analyze the 1872-2019 sea-level time series in Venice (northern Adriatic Sea, Italy) to investigate the relative role of the different driving factors in the extreme sea levels distribution. The adopted approach consists in 1) isolating the different contributions to the sea level by applying least-squares fitting and Fourier decomposition; 2) performing a multivariate statistical analysis which enables the dependencies among driving factors and their joint probability of occurrence to be described; 3) analyzing temporal changes in extreme sea levels and extrapolating possible future tendencies. The results highlight the fact that the most extreme sea levels are mainly dominated by the non-tidal residual, while the tide plays a secondary role. The non-tidal residual of the extreme sea levels is attributed mostly to PAW surge and storm surge, with the latter component becoming dominant for the most extreme events. The results of temporal evolution analysis confirm previous studies according to which the relative sea-level rise is the major driver of the increase in the frequency of floods in Venice over the last century. However, also long term variability in the storm activity impacted the frequency and intensity of extreme sea levels and have contributed to an increase of floods in Venice during the fall and winter months of the last three decades.</span></span></p>


2019 ◽  
pp. 7-22
Author(s):  
Gilbert E. Metcalf

Droughts, floods, soaring temperatures, sea-level rise, and melting ice are just some of the damages brought about by climate change. Chapter 1 details the cost of our failure to cut our emissions, from crop-destroying droughts to devastating floods. It also documents the inexorable build-up of greenhouse gases in the atmosphere as demonstrated by the Keeling curve and observations from Antarctic ice core samples. The chapter then provides a brief history of the science linking the build-up of atmospheric greenhouse gases and climate damages.


2013 ◽  
Vol 8 (2) ◽  
pp. 025005 ◽  
Author(s):  
H Machguth ◽  
P Rastner ◽  
T Bolch ◽  
N Mölg ◽  
L Sandberg Sørensen ◽  
...  
Keyword(s):  
Ice Caps ◽  

2000 ◽  
Vol 8 (4) ◽  
pp. 303-323 ◽  
Author(s):  
K Norris ◽  
P W Atkinson

Is sea-level rise and (or) climate change responsible for current declines in important coastal bird populations in Great Britain, and how might these processes affect bird populations in future? We review the current status of coastal bird populations in Britain and identify two important species, Common Redshank (Tringa totanus) and Twite (Carduelis flavirostris), whose populations are currently declining. We then review the evidence relating to the causes of these declines. There is evidence that habitat loss, driven by sea-level rise and climate change (e.g., an increase in wind and wave energy reaching the coast due to an increase in the frequency of storms), could have contributed to the decline in Twite. Common Redshank numbers are declining because of changes in grazing management, not sea-level rise. Populations that are currently stable or increasing, such as wintering waders and wildfowl, might in future experience declines in abundance because there is a link between climate, food supply, and bird abundance. There are insufficient reliable data at present to allow us to predict future changes with any confidence. Sea-level rise and climate change are currently important issues facing coastal zone management in Great Britain, and these issues may become even more pressing in future. But, in addition to these environmental processes, coastal bird populations are affected by a range of other anthropogenic factors. Conservationists, therefore, need to identify important bird populations that are (or could be in future) detrimentally affected by any of these activities rather than focusing exclusively on single issues such as sea-level rise. Allowing the sea to breach existing sea defences, thereby creating new saltmarsh, provides a way forward but is not without its practical and political difficulties.Key words: coastal birds, sea-level rise, climate change, population decline, habitat loss, saltmarsh.


2020 ◽  
Author(s):  
Wieslaw Kosek

<p>It is already well known that intra-seasonal oscillations in the Earth’s global temperature are driven by ENSO (El Niño Southern Oscillation) events. ENSO signal is also present in length of day and global sea level rise, because during El Niño the increase of the length of day and global sea level rise can be noticed. To detect common oscillations in length of day, global sea level rise, global temperature data and ENSO indices the wavelet-based semblance filtering method was used. This method, however, seeks the signals with a good phase agreement of oscillations in two time series thus, no phase agreement results in very small amplitudes of the common signals. The spectra-temporal semblance functions allow detecting the similarity of two time series in spectral bands in which the amplitudes and phases of the oscillations are consistent with each other. The amplitudes of oscillations in the considered data vary in time and in order to detect the signals with similar amplitude variations between pairs of time series the normalized Morlet wavelet transform (NMWT) and the combination of the Fourier transform bandpass filter with the Hilbert transform (FTBPF+HT) were used. These two methods enable computation of the instantaneous amplitudes and phases of oscillations in two real-valued time series. In order to detect oscillations with similar amplitude variations in two time series correlation coefficients between the amplitude variations as a function of oscillation frequencies were computed.</p>


2012 ◽  
Vol 58 (209) ◽  
pp. 427-440 ◽  
Author(s):  
Hakime Seddik ◽  
Ralf Greve ◽  
Thomas Zwinger ◽  
Fabien Gillet-Chaulet ◽  
Olivier Gagliardini

AbstractIt is likely that climate change will have a significant impact on the mass balance of the Greenland ice sheet, contributing to future sea-level rise. Here we present the implementation of the full Stokes model Elmer/Ice for the Greenland ice sheet, which includes a mesh refinement technique in order to resolve fast-flowing ice streams and outlet glaciers. We discuss simulations 100 years into the future, forced by scenarios defined by the SeaRISE (Sea-level Response to Ice Sheet Evolution) community effort. For comparison, the same experiments are also run with the shallow-ice model SICOPOLIS (SImulation COde for POLythermal Ice Sheets). We find that Elmer/Ice is ~43% more sensitive (exhibits a larger loss of ice-sheet volume relative to the control run) than SICOPOLIS for the ice-dynamic scenario (doubled basal sliding), but ~61 % less sensitive for the direct global warming scenario (based on the A1 B moderate-emission scenario for greenhouse gases). The scenario with combined A1B global warming and doubled basal sliding forcing produces a Greenland contribution to sea-level rise of ~15cm for Elmer/Ice and ~12cm for SICOPOLIS over the next 100 years.


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.


2021 ◽  
Vol 15 (2) ◽  
pp. 1015-1030 ◽  
Author(s):  
Aurélien Quiquet ◽  
Christophe Dumas

Abstract. Polar amplification will result in amplified temperature changes in the Arctic with respect to the rest of the globe, making the Greenland ice sheet particularly vulnerable to global warming. While the ice sheet has been showing an increased mass loss in the past decades, its contribution to global sea level rise in the future is of primary importance since it is at present the largest single-source contribution after the thermosteric contribution. The question of the fate of the Greenland and Antarctic ice sheets for the next century has recently gathered various ice sheet models in a common framework within the Ice Sheet Model Intercomparison Project for the Coupled Model Intercomparison Project – phase 6 (ISMIP6). While in a companion paper we present the GRISLI-LSCE (Grenoble Ice Sheet and Land Ice model of the Laboratoire des Sciences du Climat et de l'Environnement) contribution to ISMIP6-Antarctica, we present here the GRISLI-LSCE contribution to ISMIP6-Greenland. We show an important spread in the simulated Greenland ice loss in the future depending on the climate forcing used. The contribution of the ice sheet to global sea level rise in 2100 can thus be from as low as 20 mm sea level equivalent (SLE) to as high as 160 mm SLE. Amongst the models tested in ISMIP6, the Coupled Model Intercomparison Project – phase 6 (CMIP6) models produce larger ice sheet retreat than their CMIP5 counterparts. Low-emission scenarios in the future drastically reduce the ice mass loss. The oceanic forcing contributes to about 10 mm SLE in 2100 in our simulations. In addition, the dynamical contribution to ice thickness change is small compared to the impact of surface mass balance. This suggests that mass loss is mostly driven by atmospheric warming and associated ablation at the ice sheet margin. With additional sensitivity experiments we also show that the spread in mass loss is only weakly affected by the choice of the ice sheet model mechanical parameters.


2021 ◽  
Author(s):  
Steven Sandi ◽  
Jose Rodriguez ◽  
Patricia Saco ◽  
Neil Saintilan ◽  
Gerardo Riccardi

<p>Coastal wetland are known to be among the most efficient carbon burial environments around the worlds and given this high efficiency for carbon sequestration, wetland restoration and conservation efforts have been proposed as a way to potentially mitigate greenhouse emissions. The processes that lead to carbon sequestration can be quite complex and often depend on feedbacks between the type of vegetation in the wetlands, tidal flow regime, geomorphology and sediment availability. Coastal wetland vulnerability to submergence due to sea-level rise has been widely discussed in the current literature, and while wetlands could survive under some sea-level rise scenarios, accelerated rates of sea-level rise would most likely result in significant wetland losses. These can be less accentuated when accommodation space is available and the wetland is able to migrate inland, however, topography, physical barriers, and some anthropogenic factors can limit wetland migration thus decreasing the ability of wetlands to cope with sea-level rise. Potential losses of wetland vegetation under accelerated sea-level rise and limited capacity for wetlands to migrate inland are expected to affect the overall efficiency for carbon sequestration. We apply an eco-geomorphic model to simulate vegetation dynamics, carbon accumulation and overall change in carbon stocks for a restored mangrove-saltmarsh wetland experiencing accelerated sea-level rise under different management scenarios. Our results suggest that under accelerated sea-level rise and limited space for inland migration, vegetation might not be able to fully mature, reducing the capacity for sequestering carbon over time.</p>


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