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At least 469 records · Page 26Linked to original sources
PubMed1998

Dengue fever epidemic potential as projected by general circulation models of global climate change.

Climate factors influence the transmission of dengue fever, the world's most widespread vector-borne virus. We examined the potential added risk posed by global climate change on dengue transmission using computer-based simulation analysis to link temperature output from three climate general circulation models (GCMs) to a dengue vectorial capacity equation. Our outcome measure, epidemic potential, is the reciprocal of the critical mosquito density threshold of the vectorial capacity equation. An increase in epidemic potential indicates that a smaller number of mosquitoes can maintain a state of endemicity of disease where dengue virus is introduced. Baseline climate data for comparison are from 1931 to 1980. Among the three GCMs, the average projected temperature elevation was 1.16 degrees C, expected by the year 2050. All three GCMs projected a temperature-related increase in potential seasonal transmission in five selected cities, as well as an increase in global epidemic potential, with the largest area change occurring in temperate regions. For regions already at risk, the aggregate epidemic potential across the three scenarios rose on average between 31 and 47% (range, 24-74%). If climate change occurs, as many climatologists believe, this will increase the epidemic potential of dengue-carrying mosquitoes, given viral introduction and susceptible human populations. Our risk assessment suggests that increased incidence may first occur in regions bordering endemic zones in latitude or altitude. Endemic locations may be at higher risk from hemorrhagic dengue if transmission intensity increases.

Aedes↗
PubMed1998

Prevalence of adult asthma symptoms in relation to climate in New Zealand.

We conducted an ecological study linking prevalence of adult asthma symptoms with climate in the 93 New Zealand general electorates. For each electorate, the 12-month period prevalence of self-reported asthma symptoms was determined using a random sample of adults aged 20-44 on the 1991 New Zealand electoral roll. Long-term average climate was estimated using a national climate database and a geographic information system. Asthma prevalence was calculated within quartiles of the exposure variables. Independent effects of climate variables were assessed using linear regression models, with adjustment for confounding by climate, social deprivation, and geographic variables. There was a statistically significant association between asthma prevalence and mean temperature, with the lowest quartile of mean temperature having an approximately 2% lower asthma prevalence. After adjusting for confounding, there was a monotonic increase in asthma prevalence within quartiles of temperature. The results of this study are in agreement with other research suggesting a lower prevalence of asthma at low temperatures. Although on short (day-to-day) time scales, low temperatures may have a direct effect resulting in acute exacerbations of asthma symptoms, warmer average temperatures are associated with increased asthma prevalence. The reasons for this are unclear, although it is possible that on longer term (annual) time scales, higher temperatures are associated with higher levels of allergen exposure.

Adult↗
PubMed1999

An integrated assessment framework for climate change and infectious diseases.

Many potential human health effects have been hypothesized to result either directly or indirectly from global climate change. Changes in the prevalence and spread of infectious diseases are some of the most widely cited potential effects of climate change, and could have significant consequences for human health as well as economic and societal impacts. These changes in disease incidence would be mediated through biologic, ecologic, sociologic, and epidemiologic processes that interact with each other and which may themselves be influenced by climate change. Although hypothesized infectious disease effects have been widely discussed, there have not yet been thorough quantitative studies addressing the many processes at work. In part this is because of the complexity of the many indirect and feedback interactions or mechanisms that bear on all aspects of the climate issue. It also results from the difficulty of including the multitude of always-changing determinants of these diseases. This paper proposes a framework for an integrated assessment of the impacts of climate change on infectious diseases. The framework allows identification of potentially important indirect interactions or mechanisms, identification of important research gaps, and a means of integrating targeted research from a variety of disciplines into an enhanced understanding of the whole system.

Climate↗
PubMed2006

Climate change in the Seychelles: implications for water and coral reefs.

The Seychelles is a small island state in the western Indian Ocean that is vulnerable to the effects of climate change. This vulnerability led the Intergovernmental Panel on Climate Change (IPCC) in 2001 to express concern over the potential economic and social consequences that may be faced by small island states. Small island states should be prepared to adapt to such changes, especially in view of their dependence on natural resources, such as water and coral reefs, to meet basic human welfare needs. Analysis of long-term data for precipitation, air temperature, and sea-surface temperature indicated that changes are already observable in the Seychelles. The increase in dry spells that resulted in drought conditions in 1999 and the 1998 mass coral bleaching are indicative of the events that are likely to occur under future climate change. Pre-IPCC Third Assessment Report scenarios and the new SRES scenarios are compared for changes in precipitation and air surface temperature for the Seychelles. These intercomparisons indicate that the IS92 scenarios project a much warmer and wetter climate for the Seychelles than do the SRES scenarios. However, a wetter climate does not imply readily available water, but rather longer dry spells with more intense precipitation events. These observations will likely place enormous pressures on water-resources management in the Seychelles. Similarly, sea-surface temperature increases predicted by the HADCM3 model will likely trigger repeated coral-bleaching episodes, with possible coral extinctions within the Seychelles region by 2040. The cover of many coral reefs around the Seychelles have already changed, and the protection of coral-resilient areas is a critical adaptive option.

Animals↗
PubMed2002

The effects of climatic factors on the distribution and abundance of malaria vectors in Kenya.

Since 1988 malaria epidemics have occurred in multiple sites in western Kenya highlands. Climatic variability has been associated with some of the recent epidemics. We examined influences of climatic factors on the distribution and abundance of three malaria vector species, Anopheles gambiae, Anopheles arabiensis, and Anopheles funestus in western Kenya and in the Great Rift Valley. Mosquito samples were collected from the lowland and highland areas with various climatic conditions. The three vector species were abundant in the lower part of western Kenya. An. arabiensis was not found in the areas above 1,400 m elevation in western Kenya Although An. gambiae and An. funestus were found in the sites above 1,700 m in western Kenya, their densities were < 1 per house. In the Great Rift Valley, An. gambiae was not recorded. An. funestus was more widely distributed than the other two species. A stepwise multiple regression analysis found that moisture index was the most important variable in shaping species composition of the An. gambiae complex. Relative abundance of An. gambiae was positively associated with moisture index, suggesting that An. gambiae is more adapted to moist climate. Seasonal differences in species composition were significant in western Kenya, and the proportion of An. funestus was higher in the dry season than the rainy season. Influence of temperature on vector density was significant for all three species. These results imply that climate changes alter the distribution and abundance of malaria vectors in future.

Animals↗
PubMed1999

Relationship between aneurysmal subarachnoid hemorrhage and climatic conditions in the subtropical region, Amami-Oshima, in Japan.

Epidemiological studies of the relationship between climate and the onset of aneurysmal subarachnoid hemorrhage (SAH) have been reported in the temperate and subarctic latitudes. However, the relationship between the incidence of aneurysmal SAH and the climatic variations in the subtropical region remains uncertain. Epidemiological analysis requires study of an extremely isolated area. This study analyzed the relationship between the onset of aneurysmal SAH and climatic conditions in the isolated subtropical island of Amami-Oshima in Japan. During an 11-year period from 1986 to 1996, 210 patients with a primary diagnosis of aneurysmal SAH were identified by computed tomography and angiography. The mean annual age-adjusted incidence of aneurysmal SAH was 15.5 per 100,000 population (10.4 for males and 20.6 for females). No significant seasonal variations in the incidence of aneurysmal SAH and admission clustering were observed in males (p > 0.05) or females (p > 0.05). Furthermore, temperature, atmospheric pressure, and relative humidity were not significantly correlated with the monthly incidence of aneurysmal SAH. However, the occurrence of aneurysmal SAH tended to be higher in both females and the elderly during the winter and spring seasons and not during other seasons. This study indicates that seasonal and climatic conditions do not strongly contribute to the incidence of aneurysmal SAH in subtropical regions. However, elderly people are affected more by climatic conditions than young people.

Adolescent↗
PubMed1998

Extension of the International Conference on Harmonization Tripartite Guideline for Stability Testing of New Drug Substances and Products to countries of climatic zones III and IV.

The International Conference on Harmonization (ICH) Tripartite Guideline "Stability Testing of New Drug Substances and Products" sets out the stability testing requirements for a registration application within the three areas of the European Union, Japan, and the United States. These areas are assigned to climatic zone II with the storage condition of 25 degrees C/60% RH. This paper describes the adjustments that are necessary to extend the guideline to countries of climatic zones III and IV. At first storage conditions were derived with 30 degrees C/35% RH for climatic zone III and 30 degrees C/70% RH for climatic zone IV. Both conditions contain a margin of safety compared to calculated and measured data in warehouses. Furthermore, they cover the extreme temperatures above 30 and 40 degrees C which may arise in these climatic zones. Six months at 40 degrees C/75% RH was fixed as storage condition for accelerated testing to assess organoleptic and physicochemical test criteria and to make predictions for chemical stability. The predictive factor is 3.3 for 30 degrees C (6 months at 40 degrees C corresponds to 20 months at 30 degrees C). Extreme temperatures which may arise during shipment are covered by the results of stress investigations (e.g., 3 months at 50 degrees C). The next adjustment is necessary for the selection of the packaging containers. They must reflect the requirements for solid, semisolid, and liquid dosage forms caused by the two storage conditions. In the evaluation the temperature difference of 10 degrees C (40-30 degrees C) instead of 15 degrees C has to be considered, which limits the preliminary shelf lives in critical cases to 18 months instead of 24 months. Finally, statement/labeling must reflect the storage conditions. All of the other basic principles for the drug substances and drug products, such as selection and number of batches, test criteria, test procedures, specifications, testing frequency, and storage period can be applied without any change.

Climate↗
PubMed2005

The potential impact of climate change on infectious diseases of Arctic fauna.

Climate change is already affecting Arctic species including infectious disease agents and greater changes are expected. Some infectious diseases are already increasing but future changes are difficult to predict because of the complexity of host-agent-environment relationships. However mechanisms related to climate change that will influence disease patterns are understood. Warmer temperatures will benefit free living bacteria and parasites whose survival and development is limited by temperature. Warmer temperatures could promote survivability, shorter development rates and transmission. Insects such as mosquitoes and ticks that transmit disease agents may also benefit from climate change as well as the diseases they spread. Climate change will have significant impacts on biodiversity. Disease agents of species that benefit from warming will likely become more prevalent. Host species stressed by changing environmental conditions may be more vulnerable to disease agents. Warming could lead to increased agriculture and other economic opportunities in the Arctic bringing people, domestic food animals, pets and invasive species and their disease agents into Northern regions. Climate warming may also favor the release of persistent environmental pollutants some of which can affect the immune system and may favor increased rates of some diseases.

Acclimatization↗
PubMed2005

Climate change and human health: infrastructure impacts to small remote communities in the north.

In northern regions, climate change can include changes in precipitation magnitude and frequency, reductions in sea ice extent and thickness, and climate warming and cooling. These changes can increase the frequency and severity of storms, flooding, or erosion; other changes may include drought or degradation of permafrost. Climate change can result in damage to sanitation infrastructure resulting in the spread of disease or threatening a community's ability to maintain its economy, geographic location and cultural tradition, leading to mental stress. Through monitoring of some basic indicators communities can begin to develop a response to climate change. With this information, planners, engineers, health care professionals and governments can begin to develop approaches to address the challenges related to climate change.

Arctic Regions↗
PubMedDate not supplied

[Climate variability and number of deaths attributable to malaria in the Niakhar area, Senegal, from 1984 to 1996].

There are a number of reasons why climate, in certain physical and social environments, could have an impact on the epidemiology of malaria. Events, such as floods or drought, are related to the number of malaria cases and deaths, both seasonally and interannually. At a smaller scale, this study analyses the relation between climate variability and the variability in the number of deaths attributable to malaria in Niakhar, Senegal. The Niakhar area has a population of 30,000 and has been under demographic surveillance system since 1984. The rainfall in this region is highly seasonal, with a rainfall maximum in August and almost no rain between October/November and May/June. In addition to this seasonal cycle, rainfall also varies greatly from year to year (interannual variation). Over the 13 years, there were 661 deaths attributed to malaria with a marked interannual variability (range from 23 to 100, with a median of 43). There was also a strong seasonality in mortality, with nearly all deaths (89.1%) occurring between August and December. The number of deaths peaks in October, two months after the rainfall peak. Standardised monthly values were calculated for each climatic series (rainfall, relative humidity, temperature) as well as standardised five-month and monthly values of the number of deaths attributed to malaria between August and December. Correlation coefficients were calculated between these standardised values. The correlation between the variability in August rainfall and the variability in the number of deaths attributed to malaria between August and December was positive and statistically significant (r = +0.61, p = 0.02). In addition, highly significant cross-correlations were found between monthly rainfall series and monthly mortality series at one- and two-month lag (r = + 0.43, p = 0.0004 for one-month lag; r = + 0.26, p = 0.03 for two-month lag). This correlation is somewhat lower than the correlation of August rainfall alone with August to December mortality, but the result adds confidence to the signal given the increased degrees of freedom in the analysis. Similar, but slightly weaker, results were found when precipitation data were replaced with surface humidity data. Results with temperature were less clear; while temperature could in some circumstances have a direct impact on malaria, in this case here it is possible that the weak negative correlation between malaria deaths and temperature arises mainly because precipitation is physically connected to both the indices, correlating positively with malaria and negatively with temperature. The availability of a continuous demographic and medical survey since 1984 in a region of highly variable rainfall has created a rare opportunity to analyse with some confidence a climate versus malaria relationship. The findings are consistent with our understanding of the proposed link between rainfall and conditions for the reproduction of the malaria vector, leading to a lag time (here of one to two months) between anomalies of rainfall and deaths attributable to malaria. These results may have practical implications in Sub-Saharan regions marked by a great seasonal and interannual variability in rainfall by providing a simple tool to forecast the impact of climate variability on malaria mortality.

Animals↗
PubMed1989

Long-term stability of the Earth's climate.

Earth's climate has remained reasonably temperate for at least the last 3.5 billion years, despite a large increase in solar luminosity with time. The increase in solar flux has probably been offset by a decrease in atmospheric CO2 concentration caused by a negative feedback in the carbonate-silicate geochemical cycle. The same feedback mechanism implies that an Earth-like planet could remain habitable (i.e. possess liquid water) out to a least the orbit of Mars. The initial atmospheric CO2 concentration may have been much higher than the amount required to offset the lower solar output, in which case the Earth may have originally been much hotter than it is today. However, once the initial accretion period was over, Earth should have been stable against either a runaway greenhouse, that is, complete evaporation of the oceans, or against rapid loss of water. Long-term climatic evolution has thus far been studied only with one-dimensional, globally-averaged climate models. Although such models can provide a qualitative understanding of climate history, they rely on a number of assumptions that may not have been valid in the past. Some problems that deserve to be investigated with more sophisticated climate models are discussed.

Atmosphere↗
PubMedDate not supplied

Activity, climate, and postcranial robusticity: implications for modern human origins and scenarios of adaptive change.

Postcranial robusticity--the massiveness of the skeleton--figures prominently in the debate over the origin of modern humans. Anthropologists use postcranial robusticity to infer the activity levels of prehistoric populations, and changes in robusticity are often used to support scenarios of adaptive change. These scenarios explain differences in morphology as the result of a change in lifestyle (habitual activity). One common scenario posits that early modern humans were more gracile than Neandertals because the modern humans' complex culture required less physical exertion. However, lifestyle is only one of many influences on morphology. Climate has clear correlations with physique and skeletal proportions. Analysis of recent humans that differ in terms of lifestyle and climatic adaptations reveals that limb bone robusticity varies with climate as much as or more than with lifestyle. Many of the differences in robusticity between Neandertals and early modern humans appear to be related to climatic adaptations. The results support the single-recent origin model of modern human origins. The differences in robusticity between Neandertals and early modern humans suggest that population replacement rather than local evolution best explains the emergence of modern humans in Europe. Both climatic adaptations (primarily body proportions) and lifestyle should be considered in analyses of robusticity.

Activities of Daily Living↗
PubMed2000

[Relationship between main vegetation types and climatic factors in Inner Mongolia].

The relationship between main vegetation types and climate factors in Inner Mongolia was analyzed by using up-to-date vegetation map, statistics, modeling and spatial simulation of regional climatic factors under the support of GIS. The feasible climatic range of spatial distribution of plant communities was derived from overlaying vegetation map and climate maps. The results showed that the vegetation distribution was obviously in accordance with climate. On the one hand, all the types, not only zonal vegetation, but also mountain, sandy land and low land communities changed gradually from east to west due to the distance to oceans, with a zonal differentiation, Precipitation played an important role in determining this regulation. On the other hand, latitudinal replacement of plant communities occurred with the change of temperature from north to south. In addition, temperature was also the key factor controlling the spatial distribution of vegetation types, such as meadow, steppe, shrub and low land communities on the east and west sides of Daxinganling Mountains.

China↗
PubMedDate not supplied

[Season of birth and climate as determinants of infant mortality in the mainland part of the Kingdom of Sardinia].

The authors extend earlier work on the impact of climate and culture on child survival in nineteenth-century Italy. They find that "new data for the Kingdom of Sardinia during 1828-37 confirm the preeminence of cultural factors related to child care over pure climatic causes. In the French speaking Savoy, with a continental climate, differences between infant mortality of the winter and of the summer cohorts are very small. In Piedmont, with the same climate, infant mortality of the winter cohort was 35% higher than infant mortality of the summer cohort. In Liguria, with a mild climate because of maritime influence, the differences between winter and summer cohorts are reduced but still evident, Nice being closer to Liguria than to the other French speaking areas." (SUMMARY IN ENG AND FRE)

Climate↗
PubMed2002

How will the tundra-taiga interface respond to climate change?

The intuitive and logical answer to the question of how the tundra-taiga interface will react to global warming is that it should move north and this is mirrored by many models of potential treeline migration. Northward movement may be the eventual outcome if climatic warming persists over centuries or millennia. However, closer examination of the tundra-taiga interface across its circumpolar extent reveals a more complex situation. The regional climatic history of the tundra-taiga interface is highly varied, and consequently it is to be expected that the forest tundra boundary zone will respond differently to climate change depending on local variations in climate, evolutionary history, soil development, and hydrology. Investigations reveal considerable stability at present in the position of the treeline and while there may be a long-term advance northwards there are oceanic regions where climatic warming may result in a retreat southwards due to increased bog development. Reinforcing this trend is an increasing human impact, particularly in the forest tundra of Russia, which forces the limit of the forested areas southwards. Local variations will therefore require continued observation and research, as they will be of considerable importance economically as well as for ecology and conservation.

Arctic Regions↗
PubMed2003

Response surfaces for climate change impact assessments in urban areas.

Assessment of the impacts of climate change in real-world water systems, such as urban drainage networks, is a research priority for IPCC (Intergovernmental Panel of Climate Change). The usual approach is to force a hydrological transformation model with a changed climate scenario. To tackle uncertainty, the model should be run with at least high, middle and low change scenarios. This paper shows the value of response surfaces for displaying multiple simulated responses to incremental changes in air temperature and precipitation. The example given is inflow, related to sewer infiltration, at the Lycksele waste water treatment plant. The range of plausible changes in inflow is displayed for a series of runs for eight GCMs (Global Circulation Model; ACACIA; Carter, 2002, pers. comm.). These runs are summarised by climate envelopes, one for each prediction time-slice (2020, 2050, 2080). Together, the climate envelopes and response surfaces allow uncertainty to be easily seen. Winter inflows are currently sensitive to temperature, but if average temperature rises to above zero, inflow will be most sensitive to precipitation. Spring inflows are sensitive to changes in winter snow accumulation and melt. Inflow responses are highly dependent on the greenhouse gas emission scenario and GCM chosen.

Cities↗
PubMed2004

Multi-decadal climate variability, New South Wales, Australia.

Traditional hydrological risk estimation has treated the observations of hydro-climatological extremes as being independent and identically distributed, implying a static climate risk. However, recent research has highlighted the persistence of multi-decadal epochs of distinct climate states across New South Wales (NSW), Australia. Climatological studies have also revealed multi-decadal variability in the magnitude and frequency of El Niño/Southern Oscillation (ENSO) impacts. In this paper, examples of multi-decadal variability are presented with regard to flood and drought risk. The causal mechanisms for the observed variability are then explored. Finally, it is argued that the insights into climate variability provide (a) useful lead time for forecasting seasonal hydrological risk, (b) a strong rationale for a new framework for hydrological design and (c) a strong example of natural climate variability for use in the testing of General Circulation Models of climate change.

Climate↗
PubMed2004

Making the best of climatic variability: options for upgrading rainfed farming in water scarce regions.

Coping with climatic variability for livelihood security is part of everyday life for rural communities in semi-arid and dry sub-humid savannas. Water scarcity caused by rainfall fluctuations is common, causing meteorological droughts and dry spells. However, this paper indicates, based on experiences in sub-Saharan Africa and India, that the social impact on rural societies of climatically induced droughts is exaggerated. Instead, water scarcity causing food deficits is more often caused by management induced droughts and dry spells. A conceptual framework to distinguish between manageable and unmanageable droughts is presented. It is suggested that climatic droughts require focus on social resilience building instead of land and water resource management. Focus is then set on the manageable part of climatic variability, namely the almost annual occurrence of dry spells, short 2-4 week periods of no rainfall, affecting farmer yields. On-farm experiences in savannas of sub-Saharan Africa of water harvesting systems for dry spell mitigation are presented. It is shown that bridging dry spells combined with soil fertility management can double and even triple on-farm yield levels. Combined with innovative systems to ensure maximum plant water availability and water uptake capacity, through adoption of soil fertility improvement and conservation tillage systems, there is a clear opportunity to upgrade rainfed farming systems in vulnerable savanna environments, through appropriate local management of climatic variability.

Africa↗