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| Author | : Nicole-Jeanne Schlegel |
| Publisher | : |
| Total Pages | : 0 |
| Release | : 2011 |
| Genre | : Ice sheets |
| ISBN | : |
Download Determining Greenland Ice Sheet Sensitivity to Regional Climate Change Book in PDF, ePub and Kindle
The Greenland Ice Sheet, which extends south of the Arctic Circle, is vulnerable to melt in a warming climate. Complete melt of the ice sheet would raise global sea level by about 7 meters. Prediction of how the ice sheet will react to climate change requires inputs with a high degree of spatial resolution and improved simulation of the ice-dynamical responses to evolving surface mass balance. No Greenland Ice Sheet model has yet met these requirements. A three-dimensional thermo-mechanical ice sheet model of Greenland was enhanced to address these challenges. First, it was modified to accept high-resolution surface mass balance forcings. Second, a parameterization for basal drainage (of the sort responsible for sustaining the Northeast Greenland Ice Stream) was incorporated into the model. The enhanced model was used to investigate the century to millennial-scale evolution of the Greenland Ice Sheet in response to persistent climate trends. During initial experiments, the mechanism of flow in the outlet glaciers was assumed to be independent of climate change, and the outlet glaciers' dominant behavior was to counteract changes in surface mass balance. Around much of the ice sheet, warming resulted in calving front retreat and reduction of total ice sheet discharge. Observations show, however, that the character of outlet glacier flow changes with the climate. The ice sheet model was further developed to simulate observed dynamical responses of Greenland's outlet glaciers. A phenomenological description of the relation between outlet glacier discharge and surface mass balance was calibrated against recent observations. This model was used to investigate the ice sheet's response to a hypothesized 21st century warming trend. Enhanced discharge accounted for a 60% increase in Greenland mass loss, resulting in a net sea level increment of 7.3 cm by year 2100. By this time, the average surface mass balance had become negative, and widespread marginal thinning had caused 30% of historically active calving fronts to retreat. Mass losses persisted throughout the century due to flow of dynamically responsive outlets capable of sustaining high calving rates. Thinning in these areas propagated upstream into higher elevation catchments. Large drainage basins with low-lying outlets, especially those along Greenland's west coast and those fed by the Northeast Greenland Ice Stream, were most susceptible to dynamic mass loss in the 21st century.
| Author | : Jeroen Gerlo |
| Publisher | : |
| Total Pages | : |
| Release | : 2016 |
| Genre | : |
| ISBN | : |
Download Coupling a Regional Climate Model with a Greenland Ice Sheet Model for 21st Century Climate Change Book in PDF, ePub and Kindle
| Author | : National Aeronautics and Space Administration (NASA) |
| Publisher | : Createspace Independent Publishing Platform |
| Total Pages | : 30 |
| Release | : 2018-06-16 |
| Genre | : |
| ISBN | : 9781721263622 |
Download Determining Greenland Ice Sheet Accumulation Rates from Radar Remote Sensing Book in PDF, ePub and Kindle
An important component of NASA's Program for Arctic Regional Climate Assessment (PARCA) is a mass balance investigation of the Greenland Ice Sheet. The mass balance is calculated by taking the difference between the snow accumulation and the ice discharge of the ice sheet. Uncertainties in this calculation include the snow accumulation rate, which has traditionally been determined by interpolating data from ice core samples taken throughout the ice sheet. The sparse data associated with ice cores, coupled with the high spatial and temporal resolution provided by remote sensing, have motivated scientists to investigate relationships between accumulation rate and microwave observations. Jezek, Kenneth C. Goddard Space Flight Center
| Author | : Paul Andrew Mayewski |
| Publisher | : UPNE |
| Total Pages | : 266 |
| Release | : 2012-07-03 |
| Genre | : Nature |
| ISBN | : 161168384X |
Download The Ice Chronicles Book in PDF, ePub and Kindle
An exciting account of revolutionary new discoveries for understanding the earth's climate, and their implications for future scientific research and global environmental policy.
| Author | : National Research Council |
| Publisher | : National Academies Press |
| Total Pages | : 252 |
| Release | : 2002-04-23 |
| Genre | : Science |
| ISBN | : 0309133041 |
Download Abrupt Climate Change Book in PDF, ePub and Kindle
The climate record for the past 100,000 years clearly indicates that the climate system has undergone periodic-and often extreme-shifts, sometimes in as little as a decade or less. The causes of abrupt climate changes have not been clearly established, but the triggering of events is likely to be the result of multiple natural processes. Abrupt climate changes of the magnitude seen in the past would have far-reaching implications for human society and ecosystems, including major impacts on energy consumption and water supply demands. Could such a change happen again? Are human activities exacerbating the likelihood of abrupt climate change? What are the potential societal consequences of such a change? Abrupt Climate Change: Inevitable Surprises looks at the current scientific evidence and theoretical understanding to describe what is currently known about abrupt climate change, including patterns and magnitudes, mechanisms, and probability of occurrence. It identifies critical knowledge gaps concerning the potential for future abrupt changes, including those aspects of change most important to society and economies, and outlines a research strategy to close those gaps. Based on the best and most current research available, this book surveys the history of climate change and makes a series of specific recommendations for the future.
| Author | : Lauren Brett Farnsworth |
| Publisher | : |
| Total Pages | : 136 |
| Release | : 2016 |
| Genre | : |
| ISBN | : |
Download Late Glacial and Holocene History of the Greenland Ice Sheet Margin in Nunatarssuaq, Northwestern Greenland Book in PDF, ePub and Kindle
It is uncertain as to how the Greenland Ice Sheet (GrIS) will respond to future climate changes. One means of assessing the sensitivity of the GrIS to projected climate conditions is to determine its response to past conditions. I reconstructed late glacial and Holocene (~15 ka-present) GrIS extents in the Nunatarssuaq, northwestern Greenland. I applied geomorphic mapping, 10Be surface exposure dating and 14C dating of subfossil plants to determine a chronology of past GrIS extents. I also analyzed sediment cores from a glacially fed lake. 10Be ages of boulders and bedrock exposed during deglaciation from the Last Glacial Maximum (LGM; ~26-19.5 ka) are apparently old due to 10Be inherited from prior periods of exposure. The youngest 10Be age (~15 ka) may also contain inherited 10Be but approximates the time of deglaciation. Subfossil plants transported to the GrIS margin on shear planes date to ~4.6 cal ka BP and indicate a less extensive GrIS during middle Holocene time. Geomorphic mapping documents higher levels of Nordsø, a glacial lake dammed by a more extensive GrIS margin. I constrain the age of this GrIS extent to ~3-2 ka using 14C ages of in situ subfossil plants on nunataks and 10Be ages of boulders on the drift deposited during the advance. A fresh drift occurs ~30-50 m beyond the present GrIS margin. 10Be ages of this fresh drift range from 2.2 to 0.5 ka. I interpret the youngest 10Be age (~0.5 ka) as the time the drift was exposed. 14C ages of in situ subfossil plants indicate that the GrIS was at or behind its present margin at AD ~1662-1897. I compare my record of GrIS extents to other glacial fluctuations and climate records. I find that the GrIS margin in Nunatarssuaq fluctuated at similar times as local ice masses and other GrIS margins. The middle Holocene GrIS recession occurred during relatively warm conditions registered by regional climate records and the late Holocene GrIS advances occurred during cooler conditions. I also document asynchronous GrIS margin fluctuations in Nunatarssuaq. These require further investigation to determine whether they were influenced by climate conditions or ice dynamics.
| Author | : Donald Rapp |
| Publisher | : Springer |
| Total Pages | : 844 |
| Release | : 2014-07-15 |
| Genre | : Science |
| ISBN | : 3319004557 |
Download Assessing Climate Change Book in PDF, ePub and Kindle
This updated and revised new edition of Assessing Climate Change deals with the full gamut of essential questions in relation to global warming and climate change, uniquely providing a balanced and impartial discussion of this controversial subject. It shows that most of what is “known”about the Sun, historical climates and projections for the future lacks foundation and leaves great room for doubt. Assessing Climate Change (3rd Edition) examines the credibility of the global climate models which accuse greenhouse gases of causing the temperature rise of the 20th century, and provides a better understanding of the uncertainties regarding what might lie ahead in the future. Carefully considering the “evidence” brought forward by both alarmists and skeptics, this book: • has been brought completely up to date to end 2013; • examines the measurements of near surface temperatures on Earth and how much we can rely on them; • includes hundreds of graphs showing the data; • compares the current global warming trend with past climate fluctuations; • provides a systematic review of climate change in nearly all of its aspects; • expands the discussion of potential impacts of global warming (from whatever cause); • includes nearly 1000 references specific to the climate literature.
| Author | : National Research Council |
| Publisher | : National Academies Press |
| Total Pages | : 298 |
| Release | : 2011-03-11 |
| Genre | : Science |
| ISBN | : 0309151767 |
Download Climate Stabilization Targets Book in PDF, ePub and Kindle
Emissions of carbon dioxide from the burning of fossil fuels have ushered in a new epoch where human activities will largely determine the evolution of Earth's climate. Because carbon dioxide in the atmosphere is long lived, it can effectively lock the Earth and future generations into a range of impacts, some of which could become very severe. Emissions reductions decisions made today matter in determining impacts experienced not just over the next few decades, but in the coming centuries and millennia. According to Climate Stabilization Targets: Emissions, Concentrations, and Impacts Over Decades to Millennia, important policy decisions can be informed by recent advances in climate science that quantify the relationships between increases in carbon dioxide and global warming, related climate changes, and resulting impacts, such as changes in streamflow, wildfires, crop productivity, extreme hot summers, and sea level rise. One way to inform these choices is to consider the projected climate changes and impacts that would occur if greenhouse gases in the atmosphere were stabilized at a particular concentration level. The book quantifies the outcomes of different stabilization targets for greenhouse gas concentrations using analyses and information drawn from the scientific literature. Although it does not recommend or justify any particular stabilization target, it does provide important scientific insights about the relationships among emissions, greenhouse gas concentrations, temperatures, and impacts. Climate Stabilization Targets emphasizes the importance of 21st century choices regarding long-term climate stabilization. It is a useful resource for scientists, educators and policy makers, among others.
| Author | : Intergovernmental Panel on Climate Change (IPCC) |
| Publisher | : Cambridge University Press |
| Total Pages | : 755 |
| Release | : 2022-04-30 |
| Genre | : Science |
| ISBN | : 9781009157971 |
Download The Ocean and Cryosphere in a Changing Climate Book in PDF, ePub and Kindle
The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for assessing the science related to climate change. It provides policymakers with regular assessments of the scientific basis of human-induced climate change, its impacts and future risks, and options for adaptation and mitigation. This IPCC Special Report on the Ocean and Cryosphere in a Changing Climate is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks, with a focus on resilience, risk management response options, and adaptation measures, considering both their potential and limitations. It brings together knowledge on physical and biogeochemical changes, the interplay with ecosystem changes, and the implications for human communities. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core.
| Author | : Chii-yun Tsai |
| Publisher | : |
| Total Pages | : |
| Release | : 2018 |
| Genre | : |
| ISBN | : |
Download Assessing the Uncertainties of Future Changes in Ice Sheets and Polar Climate Related to Internal Climate Variability and Climate Model Structural Uncertainties Book in PDF, ePub and Kindle
Both Greenland and Antarctic ice sheets (hereafter, GrIS and AIS) have potential to be major contributors to future sea-level rise (SLR) and pose a major risk to human societies and coastal habitats. Current projections of polar climate and future SLR due to ice sheet mass loss remain highly uncertain and the sources of associated uncertainties are complex. In this dissertation, we seek to understand uncertainty of internal and forced variabilities within the climate system, and their impacts on polar climate variability and ice sheet disintegration. Three broad scientific questions are addressed in this dissertation: (1) How internal climate variability affects projections of polar climate? (2) What is the role of internal climate variability in affecting the GrIS and AIS evolution? (3) How does polar climate respond to anomalous sea surface temperature (SST) patterns and how would the responses differ across different climate model structures? Internal climate variability, which is inherently generated within the climate system due to natural processes, has shown to be one of the major contributors to uncertainty in future climate projections. Typically, the uncertainty in future climate due to internal climate variability can be estimated by conducting a large ensemble (LE) of model simulations with same external forcing but different initial conditions. To examine the impact of internal climate variability on polar climate and ice sheet evolutions, we use climate fields from two Community Earth System Model (CESM) LE experiments to force a three-dimensional ice sheet model. We investigate and quantify the impact of internal climate variability on influencing projections of the GrIS and AIS mass losses as well as their contributions to future SLR. Based on our simulations, internal climate variability can cause about 35 mm differences in the the GrIS contribution to SLR from 2000 to 2100, and for the AIS, the differences can be up to 80 mm, which is about 20% of the total change. Moreover, using ensemble-mean climate fields as the forcing in an ice sheet model significantly underestimates the GrIS and AIS mass losses and their contributions to SLR by about 12% and 29%, respectively. On estimating polar climate sensitivity to anomalous SSTs using a suite of large-ensemble model simulations with different configurations of atmospheric models, we identify that recent summer temperature changes over Greenland are sensitive to the north Atlantic SSTs and the sensitivity patters are consistent across different atmospheric model configurations. In addition, the recent summer Greenland temperature changes can be captured by a multi-linear model based on the associated sensitivity and SST information. However, sensitivity of polar climate over the Antarctic regions to anomalous SST patterns is model-dependent and its variability cannot be fully captured using a Green's function based model driven by SST information. Overall, this dissertation aims to highlight (1) the importance of internal climate variability in projecting ice sheet mass loss over the next few centuries and (2) the estimates of sensitivity of polar climate to anomalous SSTs can be strongly model-dependent over most of the polar regions due to climate model structural uncertainty. Thus, these two types of uncertainty should be considered and further investigated when estimating the future changes in polar climate and their impact on ice sheet contribution to future SLR.
