Greenhouse Effect
Environment, Controlled
Long-term trend toward earlier breeding in an American bird: a response to global warming? (1/614)
In regions with severe winters, global warming may be expected to cause earlier onset of breeding in most animals, yet no documentation of such a trend exists in North America. In a study of marked individuals of the Mexican jay (Aphelocoma ultramarina) in southeastern Arizona, from 1971 to 1998, the mean Julian date of first clutch in the population declined significantly by 10.1 days. The date of the first nest in the population also became earlier, by 10.8 days. These changes were associated with significant trends toward increased monthly minimum temperatures on the study area, traits that are associated with the onset of breeding in this population. Significant trends from 1971 to 1997 toward warmer minimum temperatures in the months before and during the initiation of breeding were observed. These trends parallel changes in minimum temperatures and community composition in a recent study of grassland ecology in the western United States. Together, they suggest that more attention should be given to the possible ecological importance of global change in minimum temperatures. (+info)Volatile anaesthetics and the atmosphere: atmospheric lifetimes and atmospheric effects of halothane, enflurane, isoflurane, desflurane and sevoflurane. (2/614)
The atmospheric lifetimes of the halogenated anaesthetics halothane, enflurane, isoflurane, desflurane and sevoflurane with respect to reaction with the hydroxyl radical (OH.) and UV photolysis have been determined from observations of OH. reaction kinetics and UV absorption spectra. Rate coefficients for the reaction with OH radicals for all halogenated anaesthetics investigated ranged from 0.44 to 2.7 x 10(-14) cm3 molec-1 s-1. Halothane, enflurane and isoflurane showed distinct UV absorption in the range 200-350 nm. In contrast, no absorption in this wavelength range was detected for desflurane or sevoflurane. The total atmospheric lifetimes, as derived from both OH. reactivity and photolysis, were 4.0-21.4 yr. It has been calculated that up to 20% of anaesthetics enter the stratosphere. As a result of chlorine and bromine content, the ozone depletion potential (ODP) relative to chlorofluorocarbon CFC-11 varies between 0 and 1.56, leading to a contribution to the total ozone depletion in the stratosphere of approximately 1% for halothane and 0.02% for enflurane and isoflurane. Estimates of the greenhouse warming potential (GWP) relative to CFC-12 yield values of 0.02-0.14, resulting in a relative contribution to global warming of all volatile anaesthetics of approximately 0.03%. The stratospheric impact of halothane, isoflurane and enflurane and their influence on ozone depletion is of increasing importance because of decreasing chlorofluorocarbons globally. However, the influence of volatile anaesthetics on greenhouse warming is small. (+info)Global climate change. (3/614)
Most of the last 100,000 years or longer has been characterized by large, abrupt, regional-to-global climate changes. Agriculture and industry have developed during anomalously stable climatic conditions. New, high-resolution analyses of sediment cores using multiproxy and physically based transfer functions allow increasingly confident interpretation of these past changes as having been caused by "band jumps" between modes of operation of the climate system. Recurrence of such band jumps is possible and might be affected by human activities. (+info)Nonglacial rapid climate events: past and future. (4/614)
The paleoclimate record makes it clear that rapid climate shifts of the 20th century are only a subset of possible climate system behavior that might occur in the absence of glacial conditions, and that climatic surprises could be a challenge for society even in the absence of significant greenhouse warming. (+info)Sensitivity and rapidity of vegetational response to abrupt climate change. (5/614)
Rapid climate change characterizes numerous terrestrial sediment records during and since the last glaciation. Vegetational response is best expressed in terrestrial records near ecotones, where sensitivity to climate change is greatest, and response times are as short as decades. (+info)The potential health impacts of climate variability and change for the United States: executive summary of the report of the health sector of the U.S. National Assessment. (6/614)
We examined the potential impacts of climate variability and change on human health as part of a congressionally mandated study of climate change in the United States. Our author team, comprising experts from academia, government, and the private sector, was selected by the federal interagency U.S. Global Change Research Program, and this report stems from our first 18 months of work. For this assessment we used a set of assumptions and/or projections of future climates developed for all participants in the National Assessment of the Potential Consequences of Climate Variability and Change. We identified five categories of health outcomes that are most likely to be affected by climate change because they are associated with weather and/or climate variables: temperature-related morbidity and mortality; health effects of extreme weather events (storms, tornadoes, hurricanes, and precipitation extremes); air-pollution-related health effects; water- and foodborne diseases; and vector- and rodent-borne diseases. We concluded that the levels of uncertainty preclude any definitive statement on the direction of potential future change for each of these health outcomes, although we developed some hypotheses. Although we mainly addressed adverse health outcomes, we identified some positive health outcomes, notably reduced cold-weather mortality, which has not been extensively examined. We found that at present most of the U.S. population is protected against adverse health outcomes associated with weather and/or climate, although certain demographic and geographic populations are at increased risk. We concluded that vigilance in the maintenance and improvement of public health systems and their responsiveness to changing climate conditions and to identified vulnerable subpopulations should help to protect the U.S. population from any adverse health outcomes of projected climate change. (+info)Molecular analyses of novel methanotrophic communities in forest soil that oxidize atmospheric methane. (7/614)
Forest and other upland soils are important sinks for atmospheric CH(4), consuming 20 to 60 Tg of CH(4) per year. Consumption of atmospheric CH(4) by soil is a microbiological process. However, little is known about the methanotrophic bacterial community in forest soils. We measured vertical profiles of atmospheric CH(4) oxidation rates in a German forest soil and characterized the methanotrophic populations by PCR and denaturing gradient gel electrophoresis (DGGE) with primer sets targeting the pmoA gene, coding for the alpha subunit of the particulate methane monooxygenase, and the small-subunit rRNA gene (SSU rDNA) of all life. The forest soil was a sink for atmospheric CH(4) in situ and in vitro at all times. In winter, atmospheric CH(4) was oxidized in a well-defined subsurface soil layer (6 to 14 cm deep), whereas in summer, the complete soil core was active (0 cm to 26 cm deep). The content of total extractable DNA was about 10-fold higher in summer than in winter. It decreased with soil depth (0 to 28 cm deep) from about 40 to 1 microg DNA per g (dry weight) of soil. The PCR product concentration of SSU rDNA of all life was constant both in winter and in summer. However, the PCR product concentration of pmoA changed with depth and season. pmoA was detected only in soil layers with active CH(4) oxidation, i.e., 6 to 16 cm deep in winter and throughout the soil core in summer. The same methanotrophic populations were present in winter and summer. Layers with high CH(4) consumption rates also exhibited more bands of pmoA in DGGE, indicating that high CH(4) oxidation activity was positively correlated with the number of methanotrophic populations present. The pmoA sequences derived from excised DGGE bands were only distantly related to those of known methanotrophs, indicating the existence of unknown methanotrophs involved in atmospheric CH(4) consumption. (+info)Economic incentives for rain forest conservation across scales. (8/614)
Globally, tropical deforestation releases 20 to 30% of anthropogenic greenhouse gases. Conserving forests could reduce emissions, but the cost-effectiveness of this mechanism for mitigation depends on the associated opportunity costs. We estimated these costs from local, national, and global perspectives using a case study from Madagascar. Conservation generated significant benefits over logging and agriculture locally and globally. Nationally, however, financial benefits from industrial logging were larger than conservation benefits. Such differing economic signals across scales may exacerbate tropical deforestation. The Kyoto Protocol could potentially overcome this obstacle to conservation by creating markets for protection of tropical forests to mitigate climate change. (+info)The greenhouse effect is not a medical term, but rather a term used in the field of environmental science and meteorology. However, I can certainly provide a definition for you:
The greenhouse effect refers to the warming of Earth's surface and lower atmosphere caused by the trapping of heat by certain gases in the atmosphere, known as greenhouse gases. These gases include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases.
When sunlight reaches Earth's surface, it is absorbed and then re-emitted as heat energy, which would normally escape back into space. However, some of this heat is trapped by greenhouse gases in the atmosphere, causing the planet to warm up. This process is essential for life on Earth, as it helps to maintain a stable temperature that supports plant and animal growth.
However, human activities such as burning fossil fuels, deforestation, and agriculture have led to an increase in greenhouse gas emissions, which has caused the natural greenhouse effect to become amplified. This has resulted in global warming and climate change, with potentially serious consequences for both human health and the environment.
"Controlled Environment" is a term used to describe a setting in which environmental conditions are monitored, regulated, and maintained within certain specific parameters. These conditions may include factors such as temperature, humidity, light exposure, air quality, and cleanliness. The purpose of a controlled environment is to ensure that the conditions are optimal for a particular activity or process, and to minimize the potential for variability or contamination that could affect outcomes or results.
In medical and healthcare settings, controlled environments are used in a variety of contexts, such as:
* Research laboratories: To ensure consistent and reproducible experimental conditions for scientific studies.
* Pharmaceutical manufacturing: To maintain strict quality control standards during the production of drugs and other medical products.
* Sterile fields: In operating rooms or cleanrooms, to minimize the risk of infection or contamination during surgical procedures or sensitive medical operations.
* Medical storage: For storing temperature-sensitive medications, vaccines, or specimens at specific temperatures to maintain their stability and efficacy.
Overall, controlled environments play a critical role in maintaining safety, quality, and consistency in medical and healthcare settings.
A "carbon footprint" is not a medical term, but it is an environmental concept that has become widely used in recent years. It refers to the total amount of greenhouse gas emissions produced to directly or indirectly support human activities, usually expressed in equivalent tons of carbon dioxide (CO2).
Greenhouse gases include carbon dioxide, methane, nitrous oxide, and fluorinated gases, among others. These gases trap heat in the atmosphere and contribute to global warming and climate change.
A carbon footprint can be calculated for an individual, organization, event, or product by adding up all the emissions associated with its production, use, and disposal. This includes direct emissions from sources such as transportation, heating, and industrial processes, as well as indirect emissions from electricity generation, supply chain activities, and waste management.
Reducing carbon footprints is an important strategy for mitigating climate change and reducing the negative impacts on human health associated with a warming planet, such as increased heat-related illnesses, respiratory problems, and infectious diseases.