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PubMed2006

A combined mitigation/geoengineering approach to climate stabilization.

Projected anthropogenic warming and increases in CO2 concentration present a twofold threat, both from climate changes and from CO2 directly through increasing the acidity of the oceans. Future climate change may be reduced through mitigation (reductions in greenhouse gas emissions) or through geoengineering. Most geoengineering approaches, however, do not address the problem of increasing ocean acidity. A combined mitigation/geoengineering strategy could remove this deficiency. Here we consider the deliberate injection of sulfate aerosol precursors into the stratosphere. This action could substantially offset future warming and provide additional time to reduce human dependence on fossil fuels and stabilize CO2 concentrations cost-effectively at an acceptable level.

Journal Article↗
PubMed1998

Abrupt climate events 500,000 to 340,000 years ago: evidence from subpolar north atlantic sediments

Subpolar North Atlantic proxy records document millennial-scale climate variations 500,000 to 340,000 years ago. The cycles have an approximately constant pacing that is similar to that documented for the last glacial cycle. These findings suggest that such climate variations are inherent to the late Pleistocene, regardless of glacial state. Sea surface temperature during the warm peak of Marine Isotope Stage 11 (MIS 11) varied by 0.5 degrees to 1 degrees C, less than the 4 degrees to 4.5 degrees C estimated during times of ice growth and the 3 degrees C estimated for glacial maxima. Coherent deep ocean circulation changes were associated with glacial oscillations in sea surface temperature.

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PubMed1998

Local orbital forcing of antarctic climate change during the last interglacial

During the last interglacial, Antarctic climate changed before that of the Northern Hemisphere. Large local changes in precession forcing could have produced this pattern if there were a rectified response in sea ice cover. Results from a coupled sea ice-ocean general circulation model supported this hypothesis when it was tested for three intervals around the last interglacial. Such a mechanism may play an important role in contributing to phase offsets between Northern and Southern Hemisphere climate change for other time intervals.

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PubMed1998

Synchronous climate changes in antarctica and the north atlantic

Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.

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PubMed1999

A 0.5-million-year record of millennial-scale climate variability in the north atlantic

Long, continuous, marine sediment records from the subpolar North Atlantic document the glacial modulation of regional climate instability throughout the past 0.5 million years. Whenever ice sheet size surpasses a critical threshold indicated by the benthic oxygen isotope (delta18O) value of 3.5 per mil during each of the past five glaciation cycles, indicators of iceberg discharge and sea-surface temperature display dramatically larger amplitudes of millennial-scale variability than when ice sheets are small. Sea-surface temperature oscillations of 1 degrees to 2 degreesC increase in size to approximately 4 degrees to 6 degreesC, and catastrophic iceberg discharges begin alternating repeatedly with brief quiescent intervals. The glacial growth associated with this amplification threshold represents a relatively small departure from the modern ice sheet configuration and sea level. Instability characterizes nearly all observed climate states, with the exception of a limited range of baseline conditions that includes the current Holocene interglacial.

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PubMed1999

Complexity and climate

The climate that we experience results from both ordered forcing and chaotic behavior; the result is a system with characteristics of each. In forecasting prospective climate changes for the next century, the focus has been on the ordered system's responses to anthropogenic forcing. The chaotic component may be much harder to predict, but at this point it is not known how important it will be.

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PubMed1999

Solar cycle variability, ozone, and climate

Results from a global climate model including an interactive parameterization of stratospheric chemistry show how upper stratospheric ozone changes may amplify observed, 11-year solar cycle irradiance changes to affect climate. In the model, circulation changes initially induced in the stratosphere subsequently penetrate into the troposphere, demonstrating the importance of the dynamical coupling between the stratosphere and troposphere. The model reproduces many observed 11-year oscillations, including the relatively long record of geopotential height variations; hence, it implies that these oscillations are likely driven, at least in part, by solar variability.

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PubMed1999

Mercury in a spanish peat bog: archive of climate change and atmospheric metal deposition

A peat core from a bog in northwest Spain provides a record of the net accumulation of atmospheric mercury since 4000 radiocarbon years before the present. It was found that cold climates promoted an enhanced accumulation and the preservation of mercury with low thermal stability, and warm climates were characterized by a lower accumulation and the predominance of mercury with moderate to high thermal stability. This record can be separated into natural and anthropogenic components. The substantial anthropogenic mercury component began approximately 2500 radiocarbon years before the present, which is near the time of the onset of mercury mining in Spain. Anthropogenic mercury has dominated the deposition record since the Islamic period (8th to 11th centuries A.D.). The results shown here have implications for the global mercury cycle and also imply that the thermal lability of the accumulated mercury can be used not only to quantify the effects of human activity, but also as a new tool for quantitative paleotemperature reconstruction.

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PubMed1999

Variations in atmospheric N2O concentration during abrupt climatic changes

Nitrous oxide (N2O) is an important greenhouse gas that is presently increasing at a rate of 0.25 percent per year. Records measured along two ice cores from Summit in Central Greenland provide information about variations in atmospheric N2O concentration in the past. The record covering the past millennium reduces the uncertainty regarding the preindustrial concentration. Records covering the last glacial-interglacial transition and a fast climatic change during the last ice age show that the N2O concentration changed in parallel with fast temperature variations in the Northern Hemisphere. This provides important information about the response of the environment to global climatic changes.

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PubMed1999

The role of sub-milankovitch climatic forcing in the initiation of the northern hemisphere glaciation

Mechanisms responsible for the initiation of major glaciation in the Northern Hemisphere at about 2.75 million years ago are poorly understood. A laminated terrestrial sequence from Pula maar, Hungary, containing about 320,000 years in annual layers between 3.05 and 2. 60 million years ago, provides a detailed record of rates of climatic change across this dramatic transition. An analysis of the record implies that climatic variations at sub-Milankovitch frequencies (less than or equal to 15,000 years) were an important driving force during this transitional interval and that, as the threshold was approached, these increased in frequency and amplitude, possibly providing the final trigger for the amplification of Northern Hemisphere ice sheets.

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PubMed1999

Common dynamic structure of canada lynx populations within three climatic regions

Across the boreal forest of Canada, lynx populations undergo regular density cycles. Analysis of 21 time series from 1821 onward demonstrated structural similarity in these cycles within large regions of Canada. The observed population dynamics are consistent with a regional structure caused by climatic features, resulting in a grouping of lynx population dynamics into three types (corresponding to three climatic-based geographic regions): Pacific-maritime, Continental, and Atlantic-maritime. A possible link with the North Atlantic Oscillation is suggested.

Journal Article↗
PubMed2000

Synchronous radiocarbon and climate shifts during the last deglaciation.

Radiocarbon data from the Cariaco Basin provide calibration of the carbon-14 time scale across the period of deglaciation (15,000 to 10, 000 years ago) with resolution available previously only from Holocene tree rings. Reconstructed changes in atmospheric carbon-14 are larger than previously thought, with the largest change occurring simultaneously with the sudden climatic cooling of the Younger Dryas event. Carbon-14 and published beryllium-10 data together suggest that concurrent climate and carbon-14 changes were predominantly the result of abrupt shifts in deep ocean ventilation.

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PubMed1991

Climatic droplet keratopathy, exfoliation syndrome, and cataract.

During a countrywide survey we assessed the prevalence of climatic droplet keratopathy (CDK) in a randomised sample of 2446 subjects representative of the population of the Republic of Djibouti. The investigation of the relationship between CDK and two diseases considered to be related to exposure to ultra-violet light--namely, exfoliation syndrome and cataract--was planned as a case control study. In the rural area prevalence of CDK was five times higher than in the urban one (2.8% vs 0.5%) and varied according to districts. The highest rates were observed where the inhabitants' activities were related to the sea. The case control study revealed that the opacification of the lens was about three times commoner in patients with CDK than in patients without CDK (p = 0.03) and that the exfoliation syndrome was about six times commoner in patients with CDK than in controls of similar age, sex, climatic conditions, and lens status (p = 0.02). Moreover, we noticed that the sequelae of corneal perforations were about 30 times commoner in patients with CDK than in controls of similar age (p less than 0.00001).

Adult↗
PubMed2006

Measuring safety climate in health care.

AIM: To review quantitative studies of safety climate in health care to examine the psychometric properties of the questionnaires designed to measure this construct. METHOD: A systematic literature review was undertaken to study sample and questionnaire design characteristics (source, no of items, scale type), construct validity (content validity, factor structure and internal reliability, concurrent validity), within group agreement, and level of analysis. RESULTS: Twelve studies were examined. There was a lack of explicit theoretical underpinning for most questionnaires and some instruments did not report standard psychometric criteria. Where this information was available, several questionnaires appeared to have limitations. CONCLUSIONS: More consideration should be given to psychometric factors in the design of healthcare safety climate instruments, especially as these are beginning to be used in large scale surveys across healthcare organisations.

Attitude of Health Personnel↗
PubMed2003

Development of the approaches to work and workplace climate questionnaires for physicians.

Two questionnaires were developed to investigate the workplace learning of physicians. The Approaches to Work Questionnaire for Physicians and the Workplace Climate Questionnaire for Physicians were adapted from general measures developed by Kirby, Knapper, Evans, Carty, and Gadula. These questionnaires were administered to a random sample of Ontario physicians. Consistent with the results of Kirby et al., three dimensions of approaches to work were observed: Deep. Surface-Rational, and Surface-Disorganized. Three dimensions of workplace climate were also found, Supportive-Receptive, Choice-Independence, and Workload. Results indicate that physicians adopt primarily a Deep approach to work, but that there is a smaller tendency toward Surface-Disorganized learning, one that is strongly correlated with perceptions of heavy workload. The Deep approach was associated with work environments perceived to be Supportive-Receptive and offer Choice-Independence. The use of these questionnaires in research and practice is discussed.

Adult↗
PubMed1993

RMI (Resource Management Initiative) and quality--getting the climate right.

The literature on the Resource Management Initiative (RMI) identifies an improvement in the quality of patient care as one of its principal aims. Successful implementation of RMI requires a change in behaviour. The mechanism or process by which this is to be achieved is not clear. This paper explores the possible nature of this relationship. We suggest that an understanding of the mechanisms through which an acute hospital can influence quality is best viewed from the perspective of organisational climate. The paper suggests a normative model for exploring climate and quality linkages through the operation of six key organisational levers. The applicability of the model is discussed throughout with reference to a RM acute hospital.

Health Resources↗
PubMed2005

Relationship between therapeutic climate and treatment outcome in group-based sexual offender treatment programs.

The aim of the study was to examine the relationship between therapeutic climate and the effectiveness of CBT treatment for sexual offenders in U.K. prisons. To this end a measure of group atmosphere was administered to members and leaders of 12 treatment groups running the same prison-based sexual offender treatment program. Treatment outcome was measured using a case-by-case methodology clinically significant change analysis--to identify the percentage of individuals within each group who had significantly changed on measures of pro-offending attitudes targeted in treatment. The results of the group process measure indicated leaders generally viewed groups more positively than members. Clear differences were also found between groups (ostensibly running the same treatment program) in terms of group climate. Analysis of members' process data indicated that there was a clear relationship between how cohesive the members reported the group to be and the extent to which freedom of action and expressions of feelings were encouraged in groups, as well as treatment outcome as measured by significant reductions in pro-offending attitudes. These results are discussed in terms of what they say about attitudes and goals of those involved in running treatment and how the effectiveness of treatment programs can be maximized.

Adult↗
PubMed2000

Effects of job characteristics, team climate, and attitudes towards clinical guidelines.

The aim of this study was to form and test a model of the antecedents and possible moderators of the use of clinical guidelines among healthcare professionals. A postal questionnaire survey of all workers in six health centres around Finland. was carried out in April 1996. The health centres were selected to represent all different areas of Finland. A total of 748 (65.5%) of the healthcare workers completed and returned the questionnaire. Of the respondents 95% were women, 16% physicians or dentists, 31% registered nurses, and 27% practical nurses. It was hypothesized that besides positive attitudes towards guidelines, job characteristics and team climate affect the use of guidelines. Three alternative models of possible main and moderating effects of attitudes, job characteristics, and team climate were formed and tested. These models were tested using hierarchical regression analysis and structural equation modelling (LISREL8). All of the hypothesized main effects and the moderating effect of job characteristics between attitudes towards and the use of guidelines were supported. According to our results important factors behind the general positive or negative attitudes towards guidelines are the usefulness, reliability, practicality, and availability of the guidelines. Also, the overall individual, team, and organizational competence to follow the procedures recommended, seemed to be vital. Moreover, those whose job motivation potential was high were more ready to use clinical guidelines even when their attitudes towards guidelines were the same.

Attitude of Health Personnel↗