scholarly journals Greenland glaciers and the 'greenhouse effect', status 1991

1992 ◽  
Vol 155 ◽  
pp. 9-13
Author(s):  
R.J Braithwaite ◽  
N Reeh ◽  
A Weidick
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Global Climate Change ◽  
Greenhouse Effect ◽  
Global Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Potential Hazard ◽  
High Latitudes ◽  
Public Concern

Possible global climate change caused by increased 'greenhouse effect' continues to be a matter of international public concern. In particular, a warmer climate is expected to cause increased melting of the Greenland ice sheet, and a rise in world sea level. The Greenland ice sheet is therefore a potential hazard for low-Iying countries. Climate warming may be apparent first, and with greatest magnitude, at high latitudes so that increased melting of the Greenland ice sheet could give early warning of global climate change. For these reasons, GGU and foreign organisations are studying Greenland glaciers in connection with the 'greenhouse effect' (Fig. 1). The present review updates the note by Braithwaite (1990).

scholarly journals Greenland glaciers and the 'greenhouse effect', activities 1993

1994 ◽  
Vol 160 ◽  
pp. 80-82
Author(s):  
R.J Braithwaite ◽  
O.B Olesen ◽  
N Reeh ◽  
A Weidick
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Climate Warming ◽  
Global Climate Change ◽  
Early Warning ◽  
Greenhouse Effect ◽  
Global Climate ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
High Latitudes

Possible global climate change caused by increased 'greenhouse effect' may lead to a warmer climate that will cause increased melting of the Greenland ice sheet, and a rise in world sea level. Climate warming may be apparent first and with greatest magnitude at high latitudes so that increased melting of the Greenland ice sheet could give early warning of global climate change. For these reasons, GGU and foreign organisations are studying Greenland glaciers in connection with the ‘greenhouse effect’ (Braithwaite et al. 1992).

Glaciological investigations on ice-sheet response in South Greenland

2002 ◽  
pp. 150-156 ◽  
Author(s):  
Christoph Mayer ◽  
Carl E. Bøggild ◽  
Steffen Podlech ◽  
Ole B. Olesen ◽  
Andreas P. Ahlstrøm ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Global Climate ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Field Work ◽  
Scientific Debate ◽  
History Of ◽  
Inland Ice

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Mayer, C., Bøggild, C. E., Podlech, S., Olesen, O. B., Ahlstrøm, A. P., & Krabill, W. (2002). Glaciological investigations on ice-sheet response in South Greenland. Geology of Greenland Survey Bulletin, 191, 150-156. https://doi.org/10.34194/ggub.v191.5143 _______________ The reaction of the world’s large ice sheets to global climate change is still in the focus of scientific debate. Recent investigations have shown pronounced thinning in the southern part of the Greenland ice sheet (Inland Ice). In order to investigate the cause of the observed thinning and to judge the sensitivity of this part of the ice sheet a combined field work, remote sensing and modelling project was designed. A glaciological transect was established in May 2001 on one of the main outlet glaciers in South Greenland (Fig. 1), and the first data are now available. In addition, the history of the glacier variations during the last 40 years has been reconstructed.

scholarly journals Greenland glaciers and the 'greenhouse effect'

1990 ◽  
Vol 148 ◽  
pp. 51-53
Author(s):  
R.J Braithwaite
Keyword(s):  
Electric Power ◽  
Sea Level ◽  
Greenhouse Effect ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Glacier Retreat ◽  
Public Concern ◽  
Power Stations ◽  
Made In

Glacier studies have been made in Greenland since the 1970s to plan hydro-electric power. However, there is also public concern about the extra melting from the Greenland ice sheet and local glaciers that may occur under a warmer climate due to the 'greenhouse effect' (Fenger & Laut, 1989). The increase in melting will cause a rapid retreat of glaciers over the next 100 years and could give serious problems for large hydro-electric power stations. More seriously, glacier retreat in Greenland will also cause a rise in world sea level. Greenland is therefore a possible hazard to all low-lying land, including Denmark.

Glaciological investigations on ice-sheet response in South Greenland

2002 ◽  
pp. 150-156
Author(s):  
Christoph Mayer ◽  
Carl E. Bøggild ◽  
Steffen Podlech ◽  
Ole B. Olesen ◽  
Andreas P. Ahlstrøm ◽  
...  
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Global Climate ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Field Work ◽  
Scientific Debate ◽  
History Of ◽  
Inland Ice

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Mayer, C., Bøggild, C. E., Podlech, S., Olesen, O. B., Ahlstrøm, A. P., & Krabill, W. (2002). Glaciological investigations on ice-sheet response in South Greenland. Geology of Greenland Survey Bulletin, 191, 150-156. https://doi.org/10.34194/ggub.v191.5144 _______________ The reaction of the world’s large ice sheets to global climate change is still in the focus of scientific debate. Recent investigations have shown pronounced thinning in the southern part of the Greenland ice sheet (Inland Ice). In order to investigate the cause of the observed thinning and to judge the sensitivity of this part of the ice sheet a combined field work, remote sensing and modelling project was designed. A glaciological transect was established in May 2001 on one of the main outlet glaciers in South Greenland (Fig. 1), and the first data are now available. In addition, the history of the glacier variations during the last 40 years has been reconstructed.

scholarly journals COSMIC-RAY-DRIVEN REACTION AND GREENHOUSE EFFECT OF HALOGENATED MOLECULES: CULPRITS FOR ATMOSPHERIC OZONE DEPLETION AND GLOBAL CLIMATE CHANGE

2013 ◽  
Vol 27 (17) ◽  
pp. 1350073 ◽  
Author(s):  
Q.-B. LU
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Global Climate Change ◽  
Greenhouse Effect ◽  
Ozone Depletion ◽  
Global Climate ◽  
Cosmic Ray ◽  
Atmospheric Ozone ◽  
Global Surface Temperature ◽  
Global Surface

This study is focused on the effects of cosmic rays (solar activity) and halogen-containing molecules (mainly chlorofluorocarbons — CFCs) on atmospheric ozone depletion and global climate change. Brief reviews are first given on the cosmic-ray-driven electron-induced-reaction (CRE) theory for O 3 depletion and the warming theory of halogenated molecules for climate change. Then natural and anthropogenic contributions to these phenomena are examined in detail and separated well through in-depth statistical analyses of comprehensive measured datasets of quantities, including cosmic rays (CRs), total solar irradiance, sunspot number, halogenated gases (CFCs, CCl 4 and HCFCs), CO 2, total O 3, lower stratospheric temperatures and global surface temperatures. For O 3 depletion, it is shown that an analytical equation derived from the CRE theory reproduces well 11-year cyclic variations of both polar O 3 loss and stratospheric cooling, and new statistical analyses of the CRE equation with observed data of total O 3 and stratospheric temperature give high linear correlation coefficients ≥ 0.92. After the removal of the CR effect, a pronounced recovery by 20 ~ 25 % of the Antarctic O 3 hole is found, while no recovery of O 3 loss in mid-latitudes has been observed. These results show both the correctness and dominance of the CRE mechanism and the success of the Montreal Protocol. For global climate change, in-depth analyses of the observed data clearly show that the solar effect and human-made halogenated gases played the dominant role in Earth's climate change prior to and after 1970, respectively. Remarkably, a statistical analysis gives a nearly zero correlation coefficient (R = -0.05) between corrected global surface temperature data by removing the solar effect and CO 2 concentration during 1850–1970. In striking contrast, a nearly perfect linear correlation with coefficients as high as 0.96–0.97 is found between corrected or uncorrected global surface temperature and total amount of stratospheric halogenated gases during 1970–2012. Furthermore, a new theoretical calculation on the greenhouse effect of halogenated gases shows that they (mainly CFCs) could alone result in the global surface temperature rise of ~0.6°C in 1970–2002. These results provide solid evidence that recent global warming was indeed caused by the greenhouse effect of anthropogenic halogenated gases. Thus, a slow reversal of global temperature to the 1950 value is predicted for coming 5 ~ 7 decades. It is also expected that the global sea level will continue to rise in coming 1 ~ 2 decades until the effect of the global temperature recovery dominates over that of the polar O 3 hole recovery; after that, both will drop concurrently. All the observed, analytical and theoretical results presented lead to a convincing conclusion that both the CRE mechanism and the CFC-warming mechanism not only provide new fundamental understandings of the O 3 hole and global climate change but have superior predictive capabilities, compared with the conventional models.

scholarly journals Large and irreversible future decline of the Greenland ice-sheet

2020 ◽  
Author(s):  
Jonathan M. Gregory ◽  
Steven E. George ◽  
Robin S. Smith
Keyword(s):  
Climate Change ◽  
Steady State ◽  
Sea Level ◽  
General Circulation ◽  
Initial Perturbation ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Circulation Model ◽  
Intergovernmental Panel ◽  
Recent Climate

Abstract. We have studied the evolution of the Greenland ice-sheet under a range of constant climates typical of those projected for the end of the present century, using a dynamical ice-sheet model (Glimmer) coupled to an atmospheric general circulation model (FAMOUS-ice AGCM). The ice-sheet surface mass balance (SMB) is simulated by the AGCM, including its dependence on altitude within AGCM gridboxes. Over millennia under a warmer climate, the ice-sheet reaches a new steady state, whose mass is correlated with the initial perturbation in SMB, and hence with the magnitude of global climate change imposed. For the largest global warming considered (about +5 K), the contribution to global-mean sea-level rise (GMSLR) is initially 2.7 mm yr−1, and the ice-sheet is eventually practically eliminated (giving over 7 m of GMSLR). For all RCP8.5 climates, final GMSLR exceeds 4 m. If recent climate were maintained, GMSLR would reach 1.5–2.5 m. Contrary to expectation from earlier work, we find no evidence for a threshold warming that divides scenarios in which the ice-sheet suffers little reduction from those which it is mostly lost. This is because the dominant effect is reduction of area, not reduction of surface altitude, and the geographical variation of SMB must be taken into account. The final steady state is achieved by withdrawal from the coast in some places, and a tendency for increasing SMB due to enhancement of cloudiness and snowfall over the remaining ice-sheet, through the effects of topographic change on atmospheric circulation. If late twentieth-century climate is restored, the ice-sheet will not regrow to its present extent, owing to such effects, once its mass has fallen below a threshold of about 4 m of sea-level equivalent. In that case, about 2 m of GMSLR would become irreversible. In order to avoid this outcome, anthropogenic climate change must be reversed before the ice-sheet has declined to the threshold mass, which would be reached in about 600 years at the highest rate of mass-loss within the likely range of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change.

scholarly journals Asynchronous Antarctic and Greenland ice-volume contributions to the last interglacial sea-level highstand

2020 ◽  
Author(s):  
Eelco Rohling ◽  
Fiona Hibbert
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Global Climate ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Climate Forcing ◽  
Potential Contribution ◽  
Last Interglacial ◽  
Ice Shelf

<p>Sea-level rise is among the greatest risks that arise from anthropogenic global climate change. It is receiving a lot of attention, among others in the IPCC reports, but major questions remain as to the potential contribution from the great continental ice sheets. In recent years, some modelling work has suggested that the ice-component of sea-level rise may be much faster than previously thought, but the rapidity of rise seen in these results depends on inclusion of scientifically debated mechanisms of ice-shelf decay and associated ice-sheet instability. The processes have not been active during historical times, so data are needed from previous warm periods to evaluate whether the suggested rates of sea-level rise are supported by observations or not. Also, we then need to assess which of the ice sheets was most sensitive, and why. The last interglacial (LIG; ~130,000 to ~118,000 years ago, ka) was the last time global sea level rose well above its present level, reaching a highstand of +6 to +9 m or more. Because Greenland Ice Sheet (GrIS) contributions were smaller than that, this implies substantial Antarctic Ice Sheet (AIS) contributions. However, this still leaves the timings, magnitudes, and drivers of GrIS and AIS reductions open to debate. I will discuss recently published sea-level reconstructions for the LIG highstand, which reveal that AIS and GrIS contributions were distinctly asynchronous, and that rates of rise to values above 0 m (present-day sea level) reached up to 3.5 m per century. Such high pre-anthropogenic rates of sea-level rise lend credibility to high rates inferred by ice modelling under certain ice-shelf instability parameterisations, for both the past and future. Climate forcing was distinctly asynchronous between the southern and northern hemispheres as well during the LIG, explaining the asynchronous sea-level contributions from AIS and GrIS. Today, climate forcing is synchronous between the two hemispheres, and also faster and greater than during the LIG. Therefore, LIG rates of sea-level rise should likely be considered minimum estimates for the future.</p>

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