Enhanced Greenhouse Effect Research Articles

Sea Level Threat in Tuvalu

Problem statement: Recently the impacts of climate change, in particular, sea level rise, had been a major concern for many Pacific island countries. In early 2000, there were a series of media coverage over sea level rise issues using Tuvalu as an example. The daily life of Tuvalu revolves around the ocean and the immediate threat on the islands people, economy, environment and its islands is of concern to the Tuvalu government. The Tuvalu government has concluded that Tuvalu was destined to become the first nation to be sunk by global warming because it is one of the smallest and lowest-lying countries in the world. Approach: In this study, sea level data from the Australian project will be focussed on despite the fact that the length of data is not sufficiently long. The AusAID funded South Pacific Sea Level and climate monitoring project was set up in response to concerns raised by Pacific island countries over the potential impacts of an enhanced greenhouse effect on climate and sea levels in the South Pacific for 20 years. Results: Based upon the 15½ years of sea level data from the project, the sea level rise rate in Tuvalu as at september 2008 was 5.9 mM year-1. This was about four times higher than the global average of 1-2 mm year-1. Sea level in the Tuvalu area had risen approximately 9.14 cm since the inception of the project 15½ years ago. However, it was to be noted that the land is quite stable and the rate of land sinking is -0.06 mM year-1 only. Accordingly, there was no significant impact on the sea level trends. Conclusion: Although the data length is just over 15 years, the sea level trend values do not fluctuate significantly since 1999. It simply indicated that the rate of sea level rise in the Tuvalu region was not accelerating as anticipated by the community.

Correction of Hydrate Dissociation in Shale Media via Correlation of Kim's Model

Deep-sea gas hydrates are ice-like crystalline substances in which hydrocarbon and non-hydrocarbon gases of specific molecular diameters are held by hydrogen bonding within rigid cages of water molecules. Sudden release of 1100-2100 Gt of carbon from dissociation of up to 10% of the global hydrate reservoir has been suggested as the cause of both the C-isotope excursion and coeval global atmospheric warming through an enhanced greenhouse effect. Kim's model assumed that, at a constant temperature, a two-step process could describe gas hydrate decomposition, including destruction of the clathrate host lattice at the surface of a particle and desorption of the guest molecule from the surface. In this paper, first, the thermodynamics and the kinetics of gas hydrate decomposition via Kim's model in the seafloors was reviewed; then, by a stainless steel test cell reactor and Omega Data Acquisition software, their correlation to sandy environments was formulated via numerical fitting of experimental data. The correlation of the conventional Kim's model is that the configuration of gas hydrate formation as a type of surface coating around sand grains was assumed. In the first stage of new mechanism dissociation, when the rate-controlling factor is dissociation heat, the formulation of the correlated dissociation rate was expressed. In the second stage of the mechanism, when the rate-controlling factor is mass transfer, the modified rate constant factor instead of Kim's constant factor was determined. The coefficient of correlation between the results of the estimation and experiment was more than 0.98 for both 85 and 216-μm sands.

Global pattern of trends in the upper atmosphere and ionosphere: Recent progress

The global pattern of long-term trends and changes in the upper atmosphere and ionosphere has been presented by Laštovička et al. [2006a. Global change in the upper atmosphere. Science 314 (5803), 1253–1254]. Trends in the mesospheric temperature, electron concentration in the lower ionosphere, electron concentration and height of its maximum in the E-region, electron concentration in the F1-region maximum, thermospheric neutral density and F-region ion temperature qualitatively agree with consequences of the enhanced greenhouse effect and form a consistent pattern of global change in the upper atmosphere. Three groups of parameters were identified as not-fitting this global pattern, the F2-region ionosphere, mesospheric water vapour, and the mesosphere/upper thermosphere dynamics. The paper reports progress in development of the global pattern of trends with emphasis to these three open problems. There are several other factors contributing to long-term trends, namely the stratospheric ozone depletion, mesospheric water vapour concentration changes, long-term changes of geomagnetic activity and of the Earth's magnetic field.

Earth's Global Energy Budget

An update is provided on the Earth's global annual mean energy budget in the light of new observations and analyses. In 1997, Kiehl and Trenberth provided a review of past estimates and performed a number of radiative computations to better establish the role of clouds and various greenhouse gases in the overall radiative energy flows, with top-of-atmosphere (TOA) values constrained by Earth Radiation Budget Experiment values from 1985 to 1989, when the TOA values were approximately in balance. The Clouds and the Earth's Radiant Energy System (CERES) measurements from March 2000 to May 2004 are used at TOA but adjusted to an estimated imbalance from the enhanced greenhouse effect of 0.9 W m−2. Revised estimates of surface turbulent fluxes are made based on various sources. The partitioning of solar radiation in the atmosphere is based in part on the International Satellite Cloud Climatology Project (ISCCP) FD computations that utilize the global ISCCP cloud data every 3 h, and also accounts for increased ...

Before and after Climate Change: The Snow Country in Australian Imaginaries

Before and after Climate Change: The Snow Country in Australian Imaginaries

How is global warming affecting our daily life in South Africa and what can we do about it?

Global warming is a steadily increasing problem that is affecting the daily lives of people all over the world, including South Africa. It has the potential to cause extensive devastation in the future if action is not taken to mitigate it. By simple definition global warming is the gradual rise in the average temperature of the earth's surface, due to the increase of certain gasses in the atmosphere. In more detail, the earth receives radiation from the sun which passes through the atmosphere as short-wave light energy. It is then absorbed by the earth's surface and re-radiated back into the atmosphere as long-wave heat energy which warms the air. There are several gasses in the atmosphere - such as carbon dioxide, methane and water vapour - that absorb this long-wave heat energy and prevent it from leaving the earth. They form an insulating layer around the earth, causing the ground and air below to be much hotter than they would be without the benefit of this layer. This is known as the natural greenhouse effect. It is essential to all life on earth because, without it, the average temperature of the earth would be too cold to sustain any type of life form. However, with the increase in greenhouse gasses being emitted into the air, the temperature on earth could rise excessively, leading to an enhanced greenhouse effect which, in effect, is global warming.

Evidence of impacts from rising temperature on inflows to the Murray‐Darling Basin

The 2001–2007 Australian drought was the hottest on record with inflows to Australia's longest river system, the Murray‐Darling, reaching an historical low. Here we examine the relative importance of rising temperature and decreasing rainfall over its catchment, the Murray Darling Basin (MDB). Although annual‐total inflow is more sensitive to rainfall over the southern MDB, where rainfall since 2001, has been the lowest on record, this alone can not explain the observed inflow decline. A relationship exists between inflow variations and fluctuations of temperature not associated with rainfall in the austral winter and spring: a rise of 1°C leads to an approximate 15% reduction in the climatological annual inflow. Our results provide strong evidence that rising temperatures due to the enhanced greenhouse effect have a strong impact on southern Australia's water resources, in addition to any reduction in rainfall, and project a long‐term decline in inflows to this river system as the greenhouse effect continues.

Impacts of grazing intensity on denitrification and N2O production in a semi-arid grassland ecosystem

N2O production from denitrification in soils contributes to the enhanced greenhouse effect and the destruction of the stratospheric ozone. Ungulate grazing affects denitrification and the production of N2O. The short-term effect of grazing on denitrification and N2O production has been examined in several grassland ecosystems. However, the effects of long-term grazing have rarely been studied. We measured denitrification and N2O production during the 2005 and 2006 growing seasons in a long-term (17 years) experiment that had five grazing intensities (GI; 0.00, 1.33, 2.67, 4.00 and 5.33 sheep ha−1). We found that denitrification and N2O production rates were seasonally variable during the measurement period, with higher values observed in summer and lower values found in spring and autumn. The grazed treatments resulted in decreased denitrification and N2O production, primarily due to the reduced soil nitrate concentration and organic N content under the long-term grazing. This supported our hypothesis that long-term over-grazing suppresses denitrification and N2O production. Although significant differences in denitrification and N2O production were not found between the four GI, there was a general trend that cumulative denitrification and N2O production decreased as grazing intensity increased, especially in 2006. Lower N losses via denitrification and N2O production in the grazed plots, to some extent, may contribute to the mitigation of greenhouse gas emission and help to preserve soil N and ameliorate the negative impacts of grazing on plant growth, productivity, and ecological restoration processes in the temperate steppe in northern China.

Methane Emissions from Free‐Ranging Cattle: Comparison of Tracer and Integrated Horizontal Flux Techniques

Accurate measurements of methane (CH4) emission rates from livestock in their undisturbed natural environments are required to assess their impacts on radiative forcing (i.e., enhanced greenhouse effect) and the environment. Here we compare results from two nonintrusive techniques for the measurement of CH4 emissions from cattle. The cows were kept in an outdoor feeding strip that allowed them to follow natural behavioral patterns but contained them within a well defined space. In the first technique, nitrous oxide (N2O) was released as a tracer at the upwind edge of the feeding strip, and the downwind concentrations of N2O and CH4 were measured simultaneously using Fourier transform infrared (FTIR) spectroscopy. Average CH4 emission per cow was calculated each half-hour on three separate days from the correlation between the two gases. The second technique was the integrated horizontal flux (IHF) or 1-D mass-balance method, in which we used the measured vertical profiles of CH4 concentration and windspeed downwind of the cows to determine the total CH4 emission. Comparing the IHF results to the known release rate of N2O allowed us to test the IHF technique independently. We found agreement within 10% for all comparisons on all days. The daily CH4 emission rate averaged over all tracer and IHF measurements was 342 g CH4 head(-1) d(-1). This is within the range of previous measurements for mature lactating dairy cattle (200-430 g CH4 head(-1) d(-1)) but higher than expected for yearling cattle. The high CH4 emissions are accompanied by high CO2 emissions determined from the FTIR measurements. The bias is most likely due to the measurements being made during and after supplementary feeding of the cattle.

해상풍력시스템의 기초침하에 관한 연구

As a national enterprise has been expanded over and over, the worldwide energy consumption has been growing necessarily. Moreover, as recently energy spendings are on the increase in countries such as BRICs, it has resulted that a rise in the price of both oil and mineral resources and instability between supply and demand become serious issue in the world resources market. The recent high price of oil and mineral resources have a deep influence on economy and threaten energy security and even national prosperity of Korea. In addition to these, exhaustion of fossil fuels and the enhanced greenhouse effect which results from gases emitted as a result of fossil fuels has been in serious questions which occur a great deal of effort to secure clean energy resources all around the world. As it is considerably possible for Korea that the Kyoto protocol may come into effect on and after 2013, it is essential to require the technological development to promote energy efficiency as well as to develope safe and renewable energy resources. The wind energy technology which converts kinetic energy into electrical energy has been in the focus of the world's attention. In this study, two-dimensional numerical analyses were conducted to observe subsidence aspects of the sea bottom on differently applied loads and various ground conditions.

A Constructivist Approach to Climate Change Teaching and Learning

AbstractIt is now broadly acknowledged that climate change due to an enhanced Greenhouse Effect is underway and such change will have major implications for our societies and environments. This paper outlines a pedagogical approach devised to encourage learning and critical thinking about climate change. A constructivist approach to teaching and learning is applied to stimulate analysis of potential impacts of climate change on systems familiar to secondary school students in South Australia. The problem‐based method guides students through a conceptualisation of the implications of environmental change. Students at Woodcroft College, when given the opportunity to examine the potential climate change impacts on a local coastal ecosystem, found the method to be both challenging and engaging. The exercise concluded with students discussing possible personal behavioural and broader societal responses to reduce the impacts of future climate change. The paper contends that such teaching to support students to become resilient young adults will be vital in a future world of environmental risk.

The economics of climate change impacts à la Stern: Novel and nuanced or rhetorically restricted?

The Stern report conducts an estimation of Greenhouse Gas control costs weighed against the benefits of avoiding damages at the global scale. As I show, Stern and colleagues are aware of the limits to CBA, although they chose to ignore the considerable literature on the subject, the many contributions by ecological economists, and especially work specific to the enhanced Greenhouse Effect. Various problems are raised or mentioned in the report including: strong uncertainty, incommensurability, plural values, non-utilitarian ethics, rights, distributional inequity, poverty, and treatment of future generations. How then can this report, acknowledging so many of those aspects of climate change that render CBA an unsuitable tool for generating policy recommendations, go ahead to conduct a global CBA and make policy recommendations? I explain how issues are suppressed and sidelined in a careful and methodical manner, with the pretence they have been addressed by ‘state of the art’ solutions. Meanwhile, the authors maintain allegiance to an economic orthodoxy which perpetuates the dominant political myth that traditional economic growth can be both sustained and answer all our problems. Besides perpetuating myths, this diverts attention away from alternative approaches, away from ethical debates over harming the innocent, the poor and future generations, and away from the fundamental changes needed to tackle the very real and serious problems current economic systems pose for environmental systems.

The relationship between adaptation and mitigation in managing climate change risks: a regional response from North Central Victoria, Australia

This two-part paper considers the complementarity between adaptation and mitigation in managing the risks associated with the enhanced greenhouse effect. Part one reviews the application of risk management methods to climate change assessments. Formal investigations of the enhanced greenhouse effect have produced three generations of risk assessment. The first led to the United Nations Intergovernmental Panel on Climate Change (IPCC), First Assessment Report and subsequent drafting of the United Nations Framework Convention on Climate Change. The second investigated the impacts of unmitigated climate change in the Second and Third IPCC Assessment Reports. The third generation, currently underway, is investigating how risk management options can be prioritised and implemented. Mitigation and adaptation have two main areas of complementarity. Firstly, they each manage different components of future climate-related risk. Mitigation reduces the number and magnitude of potential climate hazards, reducing the most severe changes first. Adaptation increases the ability to cope with climate hazards by reducing system sensitivity or by reducing the consequent level of harm. Secondly, they manage risks at different extremes of the potential range of future climate change. Adaptation works best with changes of lesser magnitude at the lower end of the potential range. Where there is sufficient adaptive capacity, adaptation improves the ability of a system to cope with increasingly larger changes over time. By moving from uncontrolled emissions towards stabilisation of greenhouse gases in the atmosphere, mitigation limits the upper part of the range. Different activities have various blends of adaptive and mitigative capacity. In some cases, high sensitivity and low adaptive capacity may lead to large residual climate risks; in other cases, a large adaptive capacity may mean that residual risks are small or non-existent. Mitigative and adaptive capacity do not share the same scale: adaptive capacity is expressed locally, whereas mitigative capacity is different for each activity and location but needs to be aggregated at the global scale to properly assess its potential benefits in reducing climate hazards. This can be seen as a demand for mitigation, which can be exercised at the local scale through exercising mitigative capacity. Part two of the paper deals with the situation where regional bodies aim to maximise the benefits of managing climate risks by integrating adaptation and mitigation measures at their various scales of operation. In north central Victoria, Australia, adaptation and mitigation are being jointly managed by a greenhouse consortium and a catchment management authority. Several related studies investigating large-scale revegetation are used to show how climate change impacts and sequestration measures affect soil, salt and carbon fluxes in the landscape. These studies show that trade-offs between these interactions will have to be carefully managed to maximise their relative benefits. The paper concludes that when managing climate change risks, there are many instances where adaptation and mitigation can be integrated at the operational level. However, significant gaps between our understanding of the benefits of adaptation and mitigation between local and global scales remain. Some of these may be addressed by matching demands for mitigation (for activities and locations where adaptive capacity will be exceeded) with the ability to supply that demand through localised mitigative capacity by means of globally integrated mechanisms.

The fire, human and climate nexus in the Sydney Basin, eastern Australia

It is widely believed that Australian Aborigines utilized fire to manage many landscapes; however, to what extent this use of fire impacted on Australia's ecosystems remains uncertain. The late Pleistocene/ Holocene fire history from three sites within the Sydney Basin (Gooches Swamp, Lake Baraba and Kings Waterhole) were compared with archaeological and palaeoclimatic data. The Gooches Swamp record appeared to be most influenced by climate and there was an abrupt increase in fire activity from the mid Holocene perhaps associated with the onset of modern El Niño-dominated conditions. The Kings Waterhole site also displayed an abrupt increase at this time, however there was a marked decrease in charcoal from ~3 ka. Similarly Lake Baraba displayed low levels of charcoal in the late Holocene. At both Kings Waterhole and Lake Baraba archaeological evidence suggests intensified human activity in the late Holocene during this period of lower and less variable charcoal. It is hence possible that Aboriginal people strongly influenced fire activity in some areas of the Sydney Basin during the late Holocene perhaps in response to the increased risk of large intense fires as an ENSO-dominated climate became more prevalent. The fire history within the Sydney Basin varies both temporally and spatially and therefore it is inappropriate to apply a single fire regime to the entire region for landscape management. This work also has implications for future fire incidence associated with climatic variability under an enhanced Greenhouse effect.

Evaluation of Surface Water and Energy Cycles in the Met Office Global NWP Model Using CEOP Data

Components of the surface water and energy balance are evaluated in the Met Office global Numerical Weather Prediction (NWP) 00-36 hour forecasts using (i) GEWEX Continental Scale Experiment (CSE) reference site data provided by the Coordinated Enhanced Observing Period (CEOP) project and (ii) other earth observing datasets from satellites and in-situ measurements. The global hydrological cycle in the model is in reasonable balance in recent model versions. However, comparison against available observations suggest that both precipitation and evaporation are overestimated over both land and ocean, with largest errors over the tropical oceans. Comparison of the model's seasonal and diurnal cycles of surface fluxes, temperature, precipitation, and moisture against the GEWEX/CEOP CSE sites during October 2002 to September 2003 reveals several issues concerning model parametrization performance. For the high latitude (Arctic) sites low cloud is overestimated during boreal winter leading to an enhanced greenhouse effect and too warm near surface temperatures in the model. Snow melt occurs too early in boreal spring in the model forecasts which currently have no snow analysis component. Possible reasons for early snow melt are discussed including the specification of albedo over heterogeneous terrain and excessive sublimation of snow in the model. The mid-latitude CEOP sites all show excessive evaporation and precipitation during boreal spring and early summer and comparison with the International Satellite Cloud Climatology (ISCCP) products show systematic under prediction of cloud cover over mid-latitude land in summer. Some of the largest biases in mid-latitude surface fluxes in summer are during daytime on non-precipitating cloudy days where the model overestimates the downward SW radiation, latent and sensible heat fluxes. Finally, over tropical land we see a tendency to underestimate precipitation which is in direct contrast to tropical oceans where precipitation accumulations are too large. We have also used the CEOP data to investigate structural errors in the vertical profiles of tropical humidity which suggest deficiencies in the convection scheme.

Abrupt change in climate and climate models

Abstract. First, we review the evidence that abrupt climate changes have occurred in the past and then demonstrate that climate models have developing capacity to simulate many of these changes. In particular, the processes by which changes in the ocean circulation drive abrupt changes appear to be captured by climate models to a degree that is encouraging. The evidence that past changes in the ocean have driven abrupt change in terrestrial systems is also convincing, but these processes are only just beginning to be included in climate models. Second, we explore the likelihood that climate models can capture those abrupt changes in climate that may occur in the future due to the enhanced greenhouse effect. We note that existing evidence indicates that a major collapse of the thermohaline circulation seems unlikely in the 21st century, although very recent evidence suggests that a weakening may already be underway. We have confidence that current climate models can capture a weakening, but a collapse in the 21st century of the thermohaline circulation is not projected by climate models. Worrying evidence of instability in terrestrial carbon, from observations and modelling studies, is beginning to accumulate. Current climate models used by the Intergovernmental Panel on Climate Change for the 4th Assessment Report do not include these terrestrial carbon processes. We therefore can not make statements with any confidence regarding these changes. At present, the scale of the terrestrial carbon feedback is believed to be small enough that it does not significantly affect projections of warming during the first half of the 21st century. However, the uncertainties in how biological systems will respond to warming are sufficiently large to undermine confidence in this belief and point us to areas requiring significant additional work.

Climatic trends associated with summerfallow in the Canadian Prairies

The Canadian Prairies have undergone important land use changes over the past 150 years. Beginning in the early 20th century, a significant portion of agricultural land was under summerfallow primarily to conserve soil moisture. The area under fallow grew to over 11 Mha, which constitute about 25% of Canada's cultivated land, and mostly remained at that level until 1975, subsequent to which improved land management practices led to significant reductions in areas under summerfallow. By 2001 summerfallow area had been reduced to 5.4 Mha, and future projections expect it to fall to 3.5 Mha. Numerous modeling studies and observations have shown that land use change can have a significant impact on regional and local climate. In the Canadian Prairies, these effects would likely be seen during the mid-June to mid-July period, when agricultural crops undergo rapid foliar expansion and substantial transpiration, thus contributing to significantly higher latent heat fluxes. Observations of 1976–2000 climate trends in the black, dark brown and brown soil zones of the Canadian Prairies showed that there have been substantial reductions in maximum temperature (1.7 °C decade −1), diurnal temperature range (1.1 °C decade −1) and solar radiation (1.2 MJ m −2 decade −1), as well as a corresponding increase in precipitation (10.3 mm decade −1) during the mid-June to July period. These findings are in opposition to trends that would be expected from climate change from an enhanced greenhouse effect, and suggest that there is substantial correspondence between reductions in summerfallow and changes in climate in the agricultural regions of the Canadian Prairies.

Changes in European ecosystem productivity and carbon balance driven by regional climate model output

AbstractClimate change resulting from the enhanced greenhouse effect together with the direct effect of increased atmospheric CO2 concentrations on vegetation growth are expected to produce changes in the cycling of carbon in terrestrial ecosystems. Impacts will vary across Europe, and regional‐scale studies are needed to resolve this variability. In this study, we used the LPJ‐GUESS ecosystem model driven by a suite of regional climate model (RCM) scenarios from the European Union (EU) project PRUDENCE to estimate climate impacts on carbon cycling across Europe. We identified similarities and discrepancies in simulated climate impacts across scenarios, particularly analyzing the uncertainties arising from the range of climate models and emissions scenarios considered. Our results suggest that net primary production (NPP) and heterotrophic respiration (Rh) will generally increase throughout Europe, but with considerable variation between European subregions. The smallest NPP increases, and in some cases decreases, occurred in the Mediterranean, where many ecosystems switched from sinks to sources of carbon by 2100, mainly as a result of deteriorating water balance. Over the period 1991–2100, modeled climate change impacts on the European carbon balance ranged from a sink of 11.6 Gt C to a source of 3.3 Gt C, the average annual sink corresponding with 1.85% of the current EU anthropogenic emissions. Projected changes in carbon balance were more dependent on the choice of the general circulation model (GCM) providing boundary conditions to the RCM than the choice of RCM or the level of anthropogenic greenhouse gases emissions.

Temperature Trends in the Lower Atmosphere

A new publication by NOAA (US National Oceanic and Atmospheric Administration) claims to have removed the previously evident discrepancies between mean global temperature anomalies measured on the surface and those measured in the lower troposphere. It claims that a combination of attention to inaccuracies and the use of linear regression equations on selected climate sequences have removed these discrepancies. This paper shows that these claims are untrue. The apparent agreement of the two sets of records for the chosen sequences is dependent on the enhanced influence of volcanoes and El Niño events in the lower troposphere, compared with an additional warming factor on the surface. If a temperature sequence comparatively free from these influences, (1979–1997) is chosen, there is no significant warming in the lower atmosphere for six of the seven records, and for the seventh, no significant warming between 1988 and 1997; whereas warming still prevails on the surface over these periods. The supposed enhanced greenhouse effect is thus currently undetectable in the lower atmosphere, where it is supposed to be most prominent, for extended periods, so the warming on the surface over these periods must have some other cause.

Inter-annual growth of Arctic charr (Salvelinus alpinus, L.) in relation to climate variation

BackgroundMajor changes in climate have been observed in the Arctic and climate models predict further amplification of the enhanced greenhouse effect at high-latitudes leading to increased warming. We propose that warming in the Arctic may affect the annual growth conditions of the cold adapted Arctic charr and that such effects can already be detected retrospectrally using otolith data.ResultsInter-annual growth of the circumpolar Arctic charr (Salvelinus alpinus, L.) was analysed in relation to climatic changes observed in the Arctic during the last two decades. Arctic charr were sampled from six locations at Qeqertarsuaq in West Greenland, where climate data have been recorded since 1990. Two fish populations met the criteria of homogeny and, consequently, only these were used in further analyses. The results demonstrate a complex coupling between annual growth rates and fluctuations in annual mean temperatures and precipitation. Significant changes in temporal patterns of growth were observed between cohorts of 1990 and 2004.ConclusionDifferences in pattern of growth appear to be a consequence of climatic changes over the last two decades and we thereby conclude that climatic affects short term and inter-annual growth as well as influencing long term shifts in age-specific growth patterns in population of Arctic charr.