Climate change and greenhouse gases

Ledley, T. S.; Sundquist, Eric T.; Schwartz, Stephen E.; Hall, Dorothy K.; Fellows, Jack D.; Killeen, T. L.

doi:10.1029/99eo00325

Cited by 125 publications

(64 citation statements)

References 128 publications

(118 reference statements)

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“…Thus there is agreement that polar climates and oceans are changing; but it seems too early, in the data gathering effort for climate modelling, for current models to lead to agreement about the extent of the change brought about by human contributions to greenhouse gases. However the consensus is that the contribution is real (Ledley et al 1999).…”

Section: Ocean Environment Changementioning

confidence: 99%

“…Increases in the concentrations of "greenhouse gases" from human activities (Ledley et al 1999) are believed to be a factor in global warming which itself is associated with changes in sea-ice positions, fluxes and glacier melt rates (Morison et al 2000;Vincent et al 2001). These changes will eventually translate into changing flows of ocean currents (Hansen et al 2001).…”

Section: Ocean Environment Changementioning

confidence: 99%

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Humans and the Southern Elephant Seal Mirounga leonina

Burton¹,

Hoff²

2002

Aust. Mammalogy

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Southern elephant seal (Mirounga leonina) populations appear remarkably unaffected by interactions with humans. They are very tolerant of close human presence whilst they are ashore for pupping, mating and moulting. Their behaviour in close proximity to helicopter operations suggests disturbance of moulting male M. leonina is minimal. There is no evidence that M. leonina have been affected by persistent organic pollutants; and few M. leonina have been reported as having been injured or killed by interactions with fishery gear. The number of prey species common to their diet and commercial fisheries in the Southern Ocean are few; but one commercial squid species, Martialia hyadesi, accounted for as much as 94% of the biomass consumed by M. leonina. Two harvested commercial squid species (Mar. hyadesi and Todarodes filippovae) were found in the stomachs of M. leonina; and some other squid species (Alluroteuthis antarcticus, Brachioteuthis spp., Gonatus antarcticus, Histeoteuthis spp., Kondokovia longimana, Moroteuthis ingens, Mor. knipovitchi, Pholidoteuthis boschmani and Psychroteuthis glacialis) have potential as commercial catch too. There is cause for concern if a future directed fishery for any of these species escalates or the by-catch of Mar. hyadesi and T. filippovae in the Illex and Nototodarus fisheries increase. There is also concern if fin-fish fisheries expand and take more of those species already taken by both M. leonina and fisheries. These species are benthic (Notothenia squamifrons), benthopelagic (Dissostichus eleginoides and Champsocephalus gunnari) and, perhaps most importantly, the pelagic myctophid species (e.g., Electrona carlsbergi).

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Section: Ocean Environment Changementioning

confidence: 99%

Section: Ocean Environment Changementioning

confidence: 99%

Humans and the Southern Elephant Seal Mirounga leonina

Burton¹,

Hoff²

2002

Aust. Mammalogy

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“…Climatologists generally agree that during the next decades and centuries, global climatic variation and extremes will likely exceed the historical record (e.g., Thompson et al 1998, Hulme andSheard 1999, US Global Change Research Program, www.usgcrp.gov). This may happen as has occurred naturally in the past (e.g., Houghton et al 1990, Crowley andNorth 1991) and/or as the lower atmosphere warms in response to increasing concentrations of anthropogenic carbon dioxide and other greenhouse gases (e.g., Mahlman 1997, Ledley et al 1999.…”

Section: Climate Changementioning

confidence: 99%

Enhanced Attenuation: A Reference Guide On Approaches To Increase The Natural Treatment Capacity Of A System

Vangelas¹

2006

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an alternative project at the Savannah River Site designed to develop cost effective and environmentally protective technical solutions for the challenge of large and complex plumes of chlorinated volatile organic compounds (cVOCs) at DOE sites. The project builds upon the current U.S. Environmental Protection Agency (EPA) protocol and directive (EPA, 1998(EPA, , 1999 for monitored natural attenuation (MNA). The DOE effort focuses on three major technical thrust areas: mass balance, enhanced attenuation (EA), and innovations in characterization/monitoring. Each of these three topics is supported by a broad-based group of recognized technical experts and each group currently is developing an interim report related to the topic area. By introducing the concepts of mass balance and EA, along with the technical basis and documentation for these concepts, the project is working toward a goal of providing new and powerful tools for transitioning from active remediation to a protective long term monitoring state. This project is a departure from classical MNA in that its central theme is to take an active part, as needed, to achieve a favorable balance between the release of contaminants from sources (source loading) and processes that destroy or retard migration of contaminants in resultant plumes (attenuation capacity of the system). OBJECTIVESThe objective of this document is to explore the realm of enhancements to natural attenuation processes for cVOCs and review examples that have been proposed, modeled, and implemented. We will identify lessons learned from these case studies to confirm that enhancements are technically feasible and have the potential to achieve a favorable, costeffective contaminant mass balance. Furthermore, we hope to determine if opportunities for further improvement of the enhancements exist and suggest areas where new and innovative types of enhancements might be possible. TARGET AUDIENCEThe intended audience for this reference guide includes state and federal regulators, stakeholders, and environmental managers, as well as environmental technology professionals. Although this diverse group is technically astute, not all users of the document will be subject-area experts for the various technologies discussed. This fact poses a significant challenge to achieve an appropriate level of technical detail. To the extent possible, enhancement technologies are covered succinctly in the main body of the document. However, supplemental information on many enhancements has been included in Appendix A so that readers seeking additional information and references can find them easily. WSRC-STI-2006-00083, Rev ORGANIZATION OF THE REPORTAn overview of the purpose of the document is presented in Section 1. The conceptual framework and organizing principles of enhancements to natural attenuation of cVOCs in the subsurface are presented in Section 2. This section contains a summary discussion of different classes of enhancements and the concept of enhancement zones is introduced. The objective of Sectio...

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“…Atmospheric CO 2 is a "greenhouse gas," so-called because it traps outgoing infrared and thermal radiation, thereby increasing near-surface temperatures. There is some evidence from climate modeling that increased atmospheric concentrations of CO 2 may be the chief contributor to "global warming," currently estimated at 0.3 -0.6 ˚C during the last 150 years (Ledley et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of CO2 Leakage From a Geologic Disposal Reservoir, Including Transitions From Super- to Subcritical Conditions, and Boiling of Liquid CO2

Pruess

2004

SPE Journal

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The critical point of CO 2 is at temperature and pressure conditions of T crit = 31.04 ˚C, P crit = 73.82 bar. At lower (subcritical) temperatures and/or pressures, CO 2 can exist in two different phase states, a liquid and a gaseous state, as well as in two-phase mixtures of these states. Disposal of CO 2 into brine formations would be made at supercritical pressures. However, CO 2 escaping from the storage reservoir may migrate upwards towards regions with lower temperatures and pressures, where CO 2 would be in subcritical conditions. An assessment of the fate of leaking CO 2 requires a capability to model not only supercritical but also subcritical CO 2 , as well as phase changes between liquid and gaseous CO 2 in sub-critical conditions. We have developed a methodology for numerically simulating the behavior of water-CO 2 mixtures in permeable media under conditions that may include liquid, gaseous, and supercritical CO 2 . This has been applied to simulations of leakage from a deep storage reservoir in which a rising CO 2 plume undergoes transitions from supercritical to subcritical conditions. We find strong cooling effects when liquid CO 2 rises to elevations where it begins to boil and evolve a gaseous CO 2 phase. A three-phase zone forms (aqueous -liquid -gas), which over time becomes several hundred meters thick as decreasing temperatures permit liquid CO 2 to advance to shallower elevations. Fluid mobilities are reduced in the three-phase region from phase interference effects. This impedes CO 2 upflow, causes the plume to spread out laterally, and gives rise to dispersed CO 2 discharge at the land surface. Our simulation suggests that temperatures along a CO 2 leakage path may decline to levels low enough so that solid water ice and CO 2 hydrate phases may be formed.

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Climate change and greenhouse gases

Cited by 125 publications

References 128 publications

Humans and the Southern Elephant Seal Mirounga leonina

Humans and the Southern Elephant Seal Mirounga leonina

Enhanced Attenuation: A Reference Guide On Approaches To Increase The Natural Treatment Capacity Of A System

Numerical Simulation of CO2 Leakage From a Geologic Disposal Reservoir, Including Transitions From Super- to Subcritical Conditions, and Boiling of Liquid CO2

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