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Results for “climate warming”

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At least 19 recordsLinked to original sources

PubMed2003

Treatment of patients with postpolio syndrome in a warm climate.

PURPOSE: Treatment in warm climate of various patient groups including patients with postpolio syndrome is controversial. METHOD: Eighty-eight patients with postpolio syndrome (61 women) were recruited, stratified according to sex, age (above/below 60 years old) and use/not use of electrical wheelchair, and randomized to three groups. Group 1 (n=30) underwent treatment in a rehabilitation centre in Tenerife for four weeks in November/December 1999. Group 2 (n=29) were treated in two similar centres in Norway for the same period of time, while Group 3 (n=29), the control group, followed their ordinary health care programme. All patients were tested at the start of study, and 3 and 6 months later, including physical tests and several questionnaire and qualitative interviews. Patients in Group 1 and 2 were also tested after the rehabilitation period. RESULTS: Group 1 and 2 improved significantly both in physical tests and subjective ratings. The positive effects in Group 1 tended to exceed the positive effects in Group 2, and the effects lasted longer. Six minutes walking distance in the two groups was 347 m and 316 m, respectively, before the treatment period, 429 m and 362 m immediately after, and 431 m and 356 m 3 months later. Subjective rating of pain (VAS-scale) was 42 and 43, respectively, before treatment, 17 and 31 immediately after, and 28 and 44 3-months later. In the control group, only minor changes were found. CONCLUSIONS: The study seems to document a positive effect of treatment of patients with postpolio syndrome in warm climate.

Adult↗

PubMed2006

Global genetic change tracks global climate warming in Drosophila subobscura.

Comparisons of recent with historical samples of chromosome inversion frequencies provide opportunities to determine whether genetic change is tracking climate change in natural populations. We determined the magnitude and direction of shifts over time (24 years between samples on average) in chromosome inversion frequencies and in ambient temperature for populations of the fly Drosophila subobscura on three continents. In 22 of 26 populations, climates warmed over the intervals, and genotypes characteristic of low latitudes (warm climates) increased in frequency in 21 of those 22 populations. Thus, genetic change in this fly is tracking climate warming and is doing so globally.

Animals↗

PubMed2006

Changing habitat associations of a thermally constrained species, the silver-spotted skipper butterfly, in response to climate warming.

1. The impact of climate change on the distribution, abundance, phenology and ecophysiology of species is already well documented, whereas the influence of climate change on habitat choice and utilization has received little attention. Here we report the changing habitat associations of a thermally constrained grassland butterfly, Hesperia comma, over 20 years. 2. Between 1982 and 2001-2, the optimum percentage of bare ground within habitat used for egg-laying shifted from 41% to 21%. 3. Egg-laying rates are temperature-dependent and females actively adjust microhabitat usage in response to temperature variations; relatively warmer host plants are chosen or oviposition at low ambient temperatures, and cooler host plants at high ambient temperatures. 4. Climate warming has increased the availability of thermally suitable habitat for H. comma at the cool, northern edge of the species' distribution, therefore increasing: (a) egg-laying rate and potentially the realized rate of population increase; (b) effective area of habitat patches as more microhabitats within a given vegetation fragment are now suitable for egg-laying; (c) buffering of populations against environmental variation as eggs are laid within a wider range of microhabitats; and (d) the number of habitat patches in the landscape that are currently available for colonization (including the use of more northerly facing aspects; Thomas et al., Nature, 2001, 411, 577-581). 5. Conservationists often assume the habitat requirements of a species to be constant, and manage habitats to maintain these conditions. For many species, these requirements are likely to change in response to climate warming, and care must be taken not to manage habitats based on outdated prescriptions.

Adaptation, Physiological↗

PubMed2001

[Treatment of patients with postpolio syndrome in warm climate].

BACKGROUND: Treatment in a warm climate of various patient groups, including patients with postpolio syndrome, is controversial. MATERIAL AND METHODS: 88 patients with postpolio syndrome (61 women) were recruited, stratified according to sex, age (<> 60 years old) and use/non-use of electrical wheelchair, and randomized to three groups. Group 1 (n = 30) underwent treatment in a rehabilitation centre in Tenerife for four weeks in November/December 1999. Group 2 (n = 29) was treated in two similar centres in Norway for the same period of time, while Group 3 (n = 29), the control group, followed their ordinary health care programme. All patients were tested at the start of the study and three and six months later with physical tests and several questionnaire and qualitative interviews. Patients in groups 1 and 2 were also tested after the rehabilitation period. RESULTS: Groups 1 and 2 improved significantly both in physical tests and subjective ratings. The positive effects in group 1 tended to exceed the positive effects in group 2, and the effects lasted longer. Six minutes walking distance in the two groups was 347 metres and 316 metres, respectively before the treatment period, 429 metres and 362 metres immediately after, and 431 metres and 356 metres three months later. Subjective rating of pain (VAS scale) was 42 and 43 respectively before treatment, 17 and 31 immediately after, and 28 and 44 three months later. In the control group, only minor changes were found. INTERPRETATION: The study seems to document a positive effect of treatment of patients with postpolio syndrome in a warm climate.

Aged↗

PubMed1996

Economic viability of crosses of Bos taurus and Bos indicus for dairying in warm climates.

Countries in the warm climatic zones need greater domestic supplies of milk. To increase yields, the option that is least expensive and most widely used is to cross dairy breed sires with local cattle. First generation crosses have more vigor than other crosses under stressful environmental conditions; growth rate, milk yield, and reproduction rate exceed those of local breeds and other crossbred combinations. On average, lactating first generation crosses are fed energy at 45 to 60% below their potential response, which limits their capabilities. Other crosses with local breeds fall short of first generation crosses as do some of the present synthetic breeds with 5/8 to 3/4 dairy breeding. Well-fed (> 2.5 maintenance needs) Holstein or Jersey crosses containing 1/4, 1/2, or 3/4 Bos indicus (Zebu) tend to follow projections of parental means for milk yield, reproduction rate, and tolerance to heat stress; however, for crosses, losses exceed predictions for lactation length, persistency of milk yield, feed efficiency, and rate of milking. Size of thoracic and abdominal organs, size of endocrine glands, stomach weight, and intestine length are lower than expected compared with values for purebreds. The smaller digestive system affects feeding intake of B. indicus crosses, and the smaller endocrine glands appear to limit responses to high energy diets. Possible directional dominance of B. indicus needs further investigation. The first generation crosses could support their use for dairy purposes if feeding rate and management were optimal, but prospects for other crosses remain questionable.

Animal Feed↗

PubMed2004

[Treatment of patients with neuromuscular disease in a warm climate].

BACKGROUND: Several patient groups request treatment in a warm climate, in spite of the fact that the effects of such treatment are undocumented. MATERIAL AND METHODS: 47 children and 40 adults with neuromuscular diseases were recruited, stratified according to sex, use or non-use of electric wheelchair, primary myopathy or hereditary neuropathy, and randomised into two adult and two children groups. The patients were treated in a rehabilitation centre, either on Lanzarote or in Norway. All patients were monitored with physical tests and questionnaires at the start of the study, at the end of the treatment period, after three months (all groups) and after six months (adults only). RESULTS: No significant differences in effect between the groups were found. In the warm climate, the adult patient group showed a statistically significant improvement regarding pain, quality of life, depression, and results of physical tests at the end of treatment. After three months, the improvement in physical tests was still present. Among adult patients treated in Norway, improvement in physical tests was statistically significant after three months, but not at the end of the treatment period. INTERPRETATION: This study did not show a statistically significant difference between patients with various neuromuscular diseases treated in a warm climate compared to similar patients treated in Norway.

Adult↗

PubMed2004

[Assessment on the impact of warming climate in winter on schistosomiasis epidemics].

OBJECTIVE: To assess the potential impact of warming climate in winter to the scale and severity of schistosomiasis epidemics in China. METHODS: Based on the data of mean temperature and monthly minimum temperature in January from 126 (out of 733) weather observation stations in China, the trend and oscillation amplitude was analyzed. The impact of warming climate in winter to the scale of schistosomiasis spreading was assessed, using the indices of 0 degrees C mean temperature and -4 degrees C mean monthly minimum temperature in January. Correlation between these two indices was analyzed. RESULTS: Evidences showed the warming climate in winter was seen all over China with the mean monthly minimum temperature and the mean temperature in January had increased 1.3 degrees C and 0.9 degrees C since 1986. The contours of mean monthly minimum temperature -4 degrees C and mean temperature 0 degrees C in January moved 1 - 2 latitudes northward. CONCLUSION: The warming climate phenomenon seen in winter was considered favorable to the living of snails in winter, resulting in the possible increase of northward spreading of snails.Thus, monitoring of snails should be paid special attention.

Animals↗

PubMed2004

[Prediction of the impact of climate warming on transmission of schistosomiasis in China].

OBJECTIVE: To predict the intensity and scale of impact on transmission of schistosomiasis japonica in China caused by the climate warming. METHODS: By using climate data from 193 weather stations in China from 1951 to 2000, the GIS database was created to analyze the tendency of average daily temperature. By using the results from the effective accumulated temperature models on Oncomelania snails and Schistosoma japonicum, the climate-transmission model for schistosomiasis was established at country level, by which the spatio-temporal analysis was performed to create the distribution maps of Oncomelania snails and Schistosoma japonicum, respectively, by means of GIS approaches based on the ratio of effective accumulated temperature to the snail or the parasite development temperature (ET/SDT) in all 193 stations. The potential distribution maps with the dispersal risk areas of schistosomiasis japonica in 2030 and 2050 were created based on forecast data that the average temperature of the country will increase by 1.7 degrees C in 2030 and by 2.2 degrees C in 2050. RESULTS: The GIS database of climate-schistosomiasis of the country was established. It was found that the average temperature in the last 5 decades inclined, especially after 1990 it increased significantly with its increasing regression formula T = 0.0198X - 28.476. The climate-transmission model for schistosomiasis was established, and it was found that the geographical distribution of Schistosoma japonicum was much larger than that of Oncomelania snails based on the ratio of ET/SDT. The prediction maps for distribution of schistosomiasis in 2030 and 2050 were created, respectively, which showed that the sensitive areas were extended with the time, the risk of expansion northward for schistosomiasis will be increasing due to directly the climate warming. CONCLUSION: It is predicted that a northward expansion of transmission area of schistosomiasis may occur due to the climate warming, the expanded potential area for schistosomiasis transmission will be important for future surveillance.

Animals↗

PubMedDate not supplied

[A response of the biota to climatic warming on Europe].

Data on the impact of climatic warming on a number of phenomena in the life of plants, animals, biocenoses, and parasitic systems of transmissible diseases are presented. Emphasis is laid on the ambiguity of responses shown by species to the same exposures, which makes any forecasting of the consequences of climatic warming very difficult, frequently unrealistic and hence it is necessary to arrange an epizootological monitoring of malaria and other transmissible diseases.

Animals↗

PubMedDate not supplied

Effects of elevated CO(2), nutrition and climatic warming on bud phenology in Sitka spruce (Picea sitchensis) and their impact on the risk of frost damage.

Effects of elevated CO(2), clone and plant nutrition on bud dormancy of Sitka spruce (Picea sitchensis (Bong.) Carr.) were examined. Sitka spruce seedlings were fumigated with ambient or elevated (ambient + 350 micro mol mol(-1)) concentrations of CO(2) in open-top chambers for three growing seasons. In 1991 and 1992, elevated CO(2) delayed bud burst in the spring and advanced bud set in the autumn. The effect of the open-top chamber on the thermal requirement for bud burst was greater than the effect of elevated CO(2) (50 and 30 day degrees (D(d)), respectively). In a second study, four clones of Sitka spruce taken from two provenances, at 43 and 54 degrees N, were fumigated with ambient or elevated CO(2). There was a large natural variation in the timing of bud burst and bud set among the clones. Elevated CO(2) had no effect on bud dormancy of the Skidegate a clone, but it reduced the growing season of the North Bend b clone by 20 days. In a third study, Sitka spruce seedlings growing in ambient or elevated CO(2), were supplied with one of three nutrient regimes, low (0.1 x potential), medium (0.5 x potential) or high (2.0 x potential), using a method and solution based on the Ingestad technique. Elevated CO(2) did not affect bud dormancy in the high-nutrient treatment, but it reduced the growing season of plants in the low-nutrient treatment by 22 days. Increasing plant nutrient supply lengthened the growing season, plants flushed earlier in the spring and set bud later in the autumn. The effects of elevated CO(2) plus a 0, 2 or 4 degrees C climatic warming on the timing of bud burst and the subsequent risk of frost damage were assessed using a simulation model and meteorological data from three sites, Edinburgh, Braemar and Masset. The model predicted that (i) doubling the CO(2) concentration in the absence of climatic warming, will delay the onset of bud burst at all three sites, (ii) climatic warming in ambient CO(2) will hasten bud burst and (iii) climatic warming in elevated CO(2) will hasten bud burst at Edinburgh and Braemar but to a lesser extent than climatic warming alone. At Masset, a 4 degrees C warming was required to advance the date of bud burst of seedlings in the elevated CO(2) treatment. At all three sites, elevated CO(2) and climatic warming increased the mean daily temperature on the date of bud burst, thus reducing the risk of subsequent frost damage.

Journal Article↗

PubMed2001

Impacts of chilling temperatures on photosynthesis in warm-climate plants.

Photosynthesis in warm-climate plants is substantially reduced after chilling. Tropical and subtropical species offer the opportunity to study the effects of low temperature on photosynthetic processes undisguised by the myriad of protective responses observed in temperate species. In this article, we highlight the primary components of photosynthesis that are affected by a short chill, in both the dark and the light, and discuss what is known of the mechanisms involved. Recent work implicates impaired redox and circadian regulation among other processes.

Carbohydrate Metabolism↗

PubMed2000

Acclimation of photosynthesis to temperature in eight cool and warm climate herbaceous C(3) species: Temperature dependence of parameters of a biochemical photosynthesis model.

To determine how parameters of a Farquhar-type photosynthesis model varied with measurement temperature and with growth temperature, eight cool and warm climate herbaceous crop and weed species were grown at 15 and 25 degrees C and single leaf carbon dioxide and water vapor exchange rates were measured over the range of 15 - 35 degrees C. Photosynthetic parameters examined were the initial slope of the response of assimilation rate (A) to substomatal carbon dioxide concentration (C(i)), A at high C(i), and stomatal conductance. The first two measurements allow calculation of V(Cmax), the maximum rate of carboxylation of ribulose bisphosphate carboxylase and J(max), the maximum rate of photosynthetic electron transport, of Farquhar-type photosynthesis models. In all species, stomatal conductance increased exponentially with temperature over the whole range of 15 - 35 degrees C, even when A decreased at high measurement temperature. There were larger increases in conductance over this temperature range in the warm climate species (4.3 x) than in the cool climate species (2.5 x). The initial slope of A vs. C(i) exhibited an optimum temperature which ranged from 20 to 30 degrees C. There was a larger increase in the optimum temperature of the initial slope at the warmer growth temperature in the cool climate species than in the warm climate species. The optimum temperature for A at high C(i) ranged from 25 to 30 degrees C among species, but changed little with growth temperature. The absolute values of both the initial slope of A vs. C(i) and A at high C(i) were increased about 10% by growth at the warmer temperature in the warm climate species, and decreased about 20% in the cool climate species. The ratio of J(max) - V(Cmax) normalized to 20 degrees C varied by more than a factor of 2 across species and growth temperatures, but differences in the temperature response of photosynthesis were more related to variation in the temperature dependencies of J(max) and V(Cmax) than to the ratio of their normalized values.

Journal Article↗

PubMed2000

Predicting spring phenology and frost damage risk of Betula spp. under climatic warming: a comparison of two models.

Timing of bud burst and frost damage risk for leaves of Betula spp. in response to climatic warming in Finland was examined with two models. In the first model, ontogenetic development in spring was triggered by an accumulation of chilling temperatures. The second model assumed an additional signal from the light climate. The two models gave radically different estimates of frost damage risk in response to climate warming. The chilling-triggered model forecast a significant and increasing risk with increased warming, whereas the light-climate-triggered model predicted little or no risk. The chilling-triggered model is widely applied in phenological research; however, there is increasing experimental evidence that light conditions play a role in the timing of spring phenology. Although it is not clear if the light response mechanisms are appropriately represented in our model, the results imply that reliance on a light signal for spring development would afford a degree of protection against possible frost damage under climate warming that would not be present if chilling were the sole determinant. Further experimental tests are required to ascertain the light-related mechanisms controlling phenological timing, so that credible model extrapolations can be undertaken.

Journal Article↗

PubMed2025

Intraspecific divergence within Microcystis aeruginosa mediates the dynamics of freshwater harmful algal blooms under climate warming scenarios.

Intraspecific biodiversity can have ecosystem-level consequences and may affect the accuracy of ecological forecasting. For example, rare genetic variants may have traits that prove beneficial under future environmental conditions. The cyanobacterium responsible for most freshwater harmful algal blooms worldwide, Microcystis aeruginosa, occurs in at least three types. While the dominant type occurs in eutrophic environments and is adapted to thrive in nutrient-rich conditions, two additional types have recently been discovered that inhabit oligotrophic and eutrophic environments and have genomic adaptations for survival under nutrient limitation. Here, we show that these oligotrophic types are widespread throughout the Eastern USA. By pairing an experimental warming study with gene expression analyses, we found that the eutrophic type may be most susceptible to climate warming. In comparison, oligotrophic types maintained their growth better and persisted longer under warming. As a mechanistic explanation for these patterns, we found that oligotrophic types responded to warming by widespread elevated expression of heat shock protein genes. Reduction of nutrient loading has been a historically effective mitigation strategy for controlling harmful algal blooms. Our results suggest that climate warming may benefit oligotrophic types of M. aeruginosa, potentially reducing the effectiveness of such mitigation efforts. In-depth study of intraspecific variation may therefore improve forecasting for understanding future whole ecosystem dynamics.

Microcystis↗

PubMed1999

Seasonal transmission of equine cyathostomes in warm climates.

Few studies investigating the seasonal transmission of equine cyathostomes have been done in warm climates. Two Australian studies used experimentally-infected plots to determine hatching, development and survival of free living stages of equine cyathostomes. Four studies in the southern United States used pasture larval counts, and in some instances tracer animals, to determine seasonal availability of infective cyathostome larvae on naturally-infected pastures. With the exception of the dry Australian tropics, a general pattern of peak transmission of cyathostomes during the cooler seasons of the year and minimal transmission during the warmest seasons was observed. Infective larvae and developing stages survived poorly in hot weather, although the rate of development was most rapid during that time. In contrast, infective larvae and developing stages survived well in cool weather, although the rate of development was slower. Adequate moisture was crucial to cyathostome transmission in warm climates, thus hot, dry weather effectively sterilized a pasture, whereas cool, moist weather was optimum for transmission. These data suggest that suppression of cyathostome egg output in feces of horses beginning shortly before the onset of cooler and/or more moist weather, and continued through the favorable period for development and survival of larvae on pasture - usually the autumn and winter should provide adequate control of these parasites. However, the efficacy of such seasonal control programs has yet to be adequately tested against that of traditional year round treatments.

Animals↗

PubMed1994

Climatic warming and increased malaria incidence in Rwanda.

Global climatic change is expected to increase the incidence of vector-borne diseases, especially malaria. This study assessed the contribution of climate to a malaria epidemic in Rwanda, focusing on the catchment area of one health centre where diagnosis was consistent and non-climatic variables well monitored. In late 1987 malaria incidence in the area increased by 337% over the 3 previous years. The increase was greatest in groups with little acquired immunity--children under 2 years (564%) and people in high-altitude areas (501%). Case-fatality rose significantly (relative risk = 4.85, p < 0.001). 1987 also saw record high temperatures and rainfall. An autoregressive equation including lagged effects of these two variables explained 80% of the variance in monthly malaria incidence. Temperature (especially mean minimum) predicted incidence best at higher altitudes where malaria had increased most. Empirically derived relations were consistent with the estimated generation time of the disease and with the known sensitivity of the plasmodium parasite to temperature. The patterns of climatic warming between day and night and among seasons will be critical to the effect on malaria. These findings are most relevant to regions near the altitude or latitude limits of the disease, where several epidemics have lately been reported.

Altitude↗

PubMed2001

20th century climate warming and tree-limit rise in the southern Scandes of Sweden.

Climate warming by ca. 0.8 degree C between the late-19th and late-20th century, although with some fluctuations, has forced multispecies elevational tree-limit advance by > 100 m for the principal tree species in the Swedish part of the Scandinavian mountain range. Predominantly, these processes imply growth in height of old-established individuals and less frequently upslope migration of new individuals. After a slight retardation during some cooler decades after 1940, a new active phase of tree-limit advance has occurred with a series of exceptionally mild winters and some warm summers during the 1990s. The magnitude of total 20th century tree-limit rise varies with topoclimate and is mainly confined to wind-sheltered and snow-rich segments of the landscape. Thickening of birch tree stands in the "advance belt" has profoundly altered the general character of the subalpine/low alpine landscape and provides a positive feedback loop for further progressive change and resilience to short-term cooling episodes. All upslope tree-limit shifts and associated landscape transformations during the 20th century have occurred without appreciable time lags, which constitutes knowledge fundamental to the generation of realistic models concerning vegetation responses to potential future warming. The new and elevated pine tree-limit may be the highest during the past 4000 14C years. Thus, it is tentatively inferred that the 20th century climate is unusually warm in a late-Holocene perspective.

Climate↗

PubMed2006

Climate warming and the risk of frost damage to boreal forest trees: identification of critical ecophysiological traits.

According to a hypothesis presented in the mid-1980s, climate warming will, paradoxically, increase the risk of frost damage to trees in the boreal and temperate zones. Dehardening and even growth onset may occur in trees during mild spells in winter and early spring, resulting in damage during subsequent periods of frost. In the present study, ecophysiological traits critical to the occurrence of frost damage in trees in the boreal zone were identified. Diagnostic computer simulations were performed to examine why one simulation model of frost hardiness in an earlier study predicted heavy frost damage as a consequence of climate warming, whereas another closely related model did not. The modeling comparison revealed that the response of ontogenetic development to air temperature during quiescence is a critical factor determining the risk of frost damage. As the response can be readily determined in growth-chamber experiments, the findings of the present study can be used to guide experimental work on the environmental regulation of the annual cycle of frost hardiness in trees.

Computer Simulation↗