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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↗

PubMed2007

CO2-forced climate and vegetation instability during Late Paleozoic deglaciation.

The late Paleozoic deglaciation is the vegetated Earth's only recorded icehouse-to-greenhouse transition, yet the climate dynamics remain enigmatic. By using the stable isotopic compositions of soil-formed minerals, fossil-plant matter, and shallow-water brachiopods, we estimated atmospheric partial pressure of carbon dioxide (pCO2) and tropical marine surface temperatures during this climate transition. Comparison to southern Gondwanan glacial records documents covariance between inferred shifts in pCO2, temperature, and ice volume consistent with greenhouse gas forcing of climate. Major restructuring of paleotropical flora in western Euramerica occurred in step with climate and pCO2 shifts, illustrating the biotic impact associated with past CO2-forced turnover to a permanent ice-free world.

Animals↗

PubMed1995

Plio-Pleistocene African climate.

Marine records of African climate variability document a shift toward more arid conditions after 2.8 million years ago (Ma), evidently resulting from remote forcing by cold North Atlantic sea-surface temperatures associated with the onset of Northern Hemisphere glacial cycles. African climate before 2.8 Ma was regulated by low-latitude insolation forcing of monsoonal climate due to Earth orbital precession. Major steps in the evolution of African hominids and other vertebrates are coincident with shifts to more arid, open conditions near 2.8 Ma, 1.7 Ma, and 1.0 Ma, suggesting that some Pliocene (Plio)-Pleistocene speciation events may have been climatically mediated.

Africa↗

PubMed2000

The relationship between mortality caused by cardiovascular diseases and two climatic factors in densely populated areas in Norway and Ireland.

BACKGROUND: Seasonal variations in mortality due to cardiovascular disease have been demonstrated in many countries, with the highest levels occurring during the coldest months of the year. It has been suggested that this can be explained by cold climate. In this study, we examined the relationship between mortality and two different climatic factors in two densely populated areas (Dublin, Ireland and Oslo/Akershus, Norway). METHODS: Meteorological data (mean daily air temperatures and wind speed) and registered daily mortality data for three groups of cardiovascular disease for the period 1985-1994 were obtained for the two respective areas. The daily mortality ratio for both men and women of 60 years and older was calculated from the mortality data. The wind chill temperature equivalent was calculated from the Siple and Passels formula. RESULTS: The seasonal variations in mortality were greater in Dublin than in Oslo/Akershus, with mortality being highest in winter. This pattern was similar to that previously shown for the two respective countries as a whole. There was a negative correlation between mortality and both air temperature and wind chill temperature equivalent for all three groups of diseases. The slopes of the linear regression lines describing the relationship between mortality and air temperature were a lot steeper for the Irish data than for the Norwegian data. However, the difference between the steepness of the linear regression lines for the relationship between mortality and wind chill temperature equivalent was considerably less between the two areas. This can be explained by the fact that Dublin is a much windier area than Oslo/Akershus. CONCLUSION: The results of this study demonstrate that the inclusion of two climatic factors rather than just one changes the impression of the relationship between climate and cardiovascular disease mortality.

Adult↗

PubMed2004

Intrinsic and climatic factors in North-American animal population dynamics.

BACKGROUND: Extensive work has been done to identify and explain multi-year cycles in animal populations. Several attempts have been made to relate these to climatic cycles. We use advanced time series analysis methods to attribute cyclicities in several North-American mammal species to abiotic vs. biotic factors. RESULTS: We study eleven century-long time series of fur-counts and three climatic records--the North Atlantic Oscillation (NAO), the El-Niño-Southern Oscillation (ENSO), and Northern Hemisphere (NH) temperatures--that extend over the same time interval. Several complementary methods of spectral analysis are applied to these 14 times series, singly or jointly. These spectral analyses were applied to the leading principal components (PCs) of the data sets. The use of both PC analysis and spectral analysis helps distinguish external from intrinsic factors that influence the dynamics of the mammal populations. CONCLUSIONS: Our results show that all three climatic indices influence the animal-population dynamics: they explain a substantial part of the variance in the fur-counts and share characteristic periods with the fur-count data set. In addition to the climate-related periods, the fur-count time series also contain a significant 3-year period that is, in all likelihood, caused by biological interactions.

Animals↗

PubMed2006

Web-based climate information resources for malaria control in Africa.

Malaria remains a major public health threat to more than 600 million Africans and its control is recognized as critical to achieving the Millennium Development Goals. The greatest burden of malaria in Africa occurs in the endemic regions where the disease pathogen is continuously present in the community. These regions are characterized by an environment that is conducive to interactions between the Anopheles mosquito, malaria parasites and human hosts, as well as housing of generally poor quality, which offers little protection from mosquito-human contact. Epidemic malaria tends to occur along the geographical margins of endemic regions, when the equilibrium between the human, parasite and mosquito vector populations is occasionally disturbed and a sharp but temporary increase in disease incidence results. When malaria control measures are inadequate, as is the case in much of sub-Saharan Africa, the disease distribution is closely linked with seasonal patterns of the climate and local environment. In the absence of good epidemiological data on malaria distribution in Africa, climate information has long been used to develop malaria risk maps that illustrate the boundaries of 'climatic suitability for endemic transmission.' The best known of these are produced by the Pan-African-based MARA Collaboration. This paper describes the development of additional malaria suitability maps which have been produced in an online, interactive format to enable temporal information (i.e., seasonality of climate conditions) to be queried and displayed along with spatial information. These maps and the seasonal information that they contain should be useful to the malaria control and health service communities for their planning and operational activities.

Africa↗

PubMed2001

Comments on the process and product of the health impacts assessment component of the national assessment of the potential consequences of climate variability and change for the United States.

In 1990 Congress formed the U.S. Global Change Research Program and required it to conduct a periodic national assessment of the potential impacts of climate variability and change on all regions and select economic/resource sectors of the United States. Between 1998 and 2000, a team of experts collaborated on a health impacts assessment that formed the basis for the first National Assessment's analysis of the potential impacts of climate on human health. The health impacts assessment was integrated across a number of health disciplines and involved a search for and qualitative expert judgment review of data on the potential links between climate events and population health. Accomplishments included identification of vulnerable populations, adaptation strategies, research needs, and data gaps. Experts, stakeholders, and the public were involved. The assessment is reported in five articles in this issue; a summary was published in the April 2000 issue of Environmental Health Perspectives. The assessment report will enhance understanding of ways human health might be affected by various climate-associated stresses and of the need for further empirical and predictive research. Improved understanding and communication of the significance and inevitability of uncertainties in such an assessment are critical to further research and policy development.

Animals↗

PubMed2006

Climate change, health, and vulnerability in Canadian northern Aboriginal communities.

BACKGROUND: Canada has recognized that Aboriginal and northern communities in the country face unique challenges and that there is a need to expand the assessment of vulnerabilities to climate change to include these communities. Evidence suggests that Canada's North is already experiencing significant changes in its climate--changes that are having negative impacts on the lives of Aboriginal people living in these regions. Research on climate change and health impacts in northern Canada thus far has brought together Aboriginal community members, government representatives, and researchers and is charting new territory. METHODS AND RESULTS: In this article we review experiences from two projects that have taken a community-based dialogue approach to identifying and assessing the effects of and vulnerability to climate change and the impact on the health in two Inuit regions of the Canadian Arctic. CONCLUSIONS: The results of the two case projects that we present argue for a multi-stakeholder, participatory framework for assessment that supports the necessary analysis, understanding, and enhancement of capabilities of local areas to respond and adapt to the health impacts at the local level.

Acclimatization↗

PubMed2004

Genetic response to climatic change: insights from ancient DNA and phylochronology.

Understanding how climatic change impacts biological diversity is critical to conservation. Yet despite demonstrated effects of climatic perturbation on geographic ranges and population persistence, surprisingly little is known of the genetic response of species. Even less is known over ecologically long time scales pertinent to understanding the interplay between microevolution and environmental change. Here, we present a study of population variation by directly tracking genetic change and population size in two geographically widespread mammal species (Microtus montanus and Thomomys talpoides) during late-Holocene climatic change. We use ancient DNA to compare two independent estimates of population size (ecological and genetic) and corroborate our results with gene diversity and serial coalescent simulations. Our data and analyses indicate that, with population size decreasing at times of climatic change, some species will exhibit declining gene diversity as expected from simple population genetic models, whereas others will not. While our results could be consistent with selection, independent lines of evidence implicate differences in gene flow, which depends on the life history strategy of species.

Animals↗

PubMed2006

Climate cycles and forecasts of cutaneous leishmaniasis, a nonstationary vector-borne disease.

BACKGROUND: Cutaneous leishmaniasis (CL) is one of the main emergent diseases in the Americas. As in other vector-transmitted diseases, its transmission is sensitive to the physical environment, but no study has addressed the nonstationary nature of such relationships or the interannual patterns of cycling of the disease. METHODS AND FINDINGS: We studied monthly data, spanning from 1991 to 2001, of CL incidence in Costa Rica using several approaches for nonstationary time series analysis in order to ensure robustness in the description of CL's cycles. Interannual cycles of the disease and the association of these cycles to climate variables were described using frequency and time-frequency techniques for time series analysis. We fitted linear models to the data using climatic predictors, and tested forecasting accuracy for several intervals of time. Forecasts were evaluated using "out of fit" data (i.e., data not used to fit the models). We showed that CL has cycles of approximately 3 y that are coherent with those of temperature and El Niño Southern Oscillation indices (Sea Surface Temperature 4 and Multivariate ENSO Index). CONCLUSIONS: Linear models using temperature and MEI can predict satisfactorily CL incidence dynamics up to 12 mo ahead, with an accuracy that varies from 72% to 77% depending on prediction time. They clearly outperform simpler models with no climate predictors, a finding that further supports a dynamical link between the disease and climate.

Animals↗

PubMed2004

Past changes in Arctic terrestrial ecosystems, climate and UV radiation.

At the last glacial maximum, vast ice sheets covered many continental areas. The beds of some shallow seas were exposed thereby connecting previously separated landmasses. Although some areas were ice-free and supported a flora and fauna, mean annual temperatures were 10-13 degrees C colder than during the Holocene. Within a few millennia of the glacial maximum, deglaciation started, characterized by a series of climatic fluctuations between about 18,000 and 11,400 years ago. Following the general thermal maximum in the Holocene, there has been a modest overall cooling trend, superimposed upon which have been a series of millennial and centennial fluctuations in climate such as the "Little Ice Age spanning approximately the late 13th to early 19th centuries. Throughout the climatic fluctuations of the last 150,000 years, Arctic ecosystems and biota have been close to their minimum extent within the most recent 10,000 years. They suffered loss of diversity as a result of extinctions during the most recent large-magnitude rapid global warming at the end of the last glacial stage. Consequently, Arctic ecosystems and biota such as large vertebrates are already under pressure and are particularly vulnerable to current and projected future global warming. Evidence from the past indicates that the treeline will very probably advance, perhaps rapidly, into tundra areas, as it did during the early Holocene, reducing the extent of tundra and increasing the risk of species extinction. Species will very probably extend their ranges northwards, displacing Arctic species as in the past. However, unlike the early Holocene, when lower relative sea level allowed a belt of tundra to persist around at least some parts of the Arctic basin when treelines advanced to the present coast, sea level is very likely to rise in future, further restricting the area of tundra and other treeless Arctic ecosystems. The negative response of current Arctic ecosystems to global climatic conditions that are apparently without precedent during the Pleistocene is likely to be considerable, particularly as their exposure to co-occurring environmental changes (such as enhanced levels of UV-B, deposition of nitrogen compounds from the atmosphere, heavy metal and acidic pollution, radioactive contamination, increased habitat fragmentation) is also without precedent.

Animals↗

PubMedDate not supplied

[Climate change in spain and risk of infectious and parasitic diseases transmitted by arthropods and rodents].

Due to Spain's being located near Africa, being a stopping-off point for migrating birds and individuals and due to its climate conditions, nearing those of areas where there are vector-borne diseases, this is a country where this type of diseases could taken on greater importance due to the climate change. The possible risk would result from the geographical spread of already established vectors or due to subtropical vectors adapted to surviving in cooler, dried climates being imported and taking up residence. Hypothetically, the vector-borne diseases subject to be influenced by the climate change in Spain would be those transmitted by dipterans, such as dengue fever, West Nile encephalitis, Rift Valley fever, malaria and leishmaniasis; tick-transmitted diseases, such as Crimean-Congo hemorrhagic fever, tick-borne encephalitis, Lyme disease, spotted fever and endemic relapsing fever; and rodent-transmitted diseases. But the greatest, most viable threat would be the Aedes albopictus mosquito, which would be capable of transmitting viral diseases such as West Nile encephalitis or dengue fever, taking up residence. But, for actual areas of endemia being established, a combination of other factors, such as the massive, simultaneous influx of animal or human reservoirs and the deterioration of the social healthcare conditions and of the Public Health services.

Animals↗

PubMed2006

Dramatic declines in mussel bed community diversity: response to climate change?

Mussel beds along the wave-exposed coast of the eastern North Pacific Ocean serve as an important habitat, harboring a high diversity of species. A comparison of California mussel bed community diversity in 2002 to historical data (1960s to 1970s) revealed large declines (mean loss 58.9%), including some declines >141 species (approximately 80% loss). Concurrent work revealed inconsistent changes in mussel populations (biomass and bed thickness) along the California coast, suggesting that diversity declines may be related to large-scale processes rather than local habitat destruction. Potential factors causing declines in mussel community diversity are discussed, with regional climate change associated with the Pacific Decadal Oscillation and climate change induced alterations of ecological interactions and biological processes suggested as likely causes. Although extensive literature has predicted the potential effects of climate change on global diversity, this study is one of the few examples of declines attributed to climate change.

Animals↗

PubMed2006

Historical climate and stream flow trends and future water demand analysis in the Calgary region, Canada.

The city of Calgary has been one of fastest growing cities in Canada in recent years. Rapid population growth and a warming climate trend have raised concerns about sustainable water supply. In this study, historic climate, stream flow and population data are analyzed in order to develop models of future climate trends and river-water resource availability. Daily water demands for the next 60 years were projected using the relationship between daily maximum temperature and water demand under simulated climate and population growth scenarios. To maintain sustainable growth Calgary will require water conservation efforts that reduce per capita water use to less than half of the current level over the next 60 years, an interval when the civic population is expected to be doubled.

Alberta↗

PubMed1992

Modelling the Phanerozoic carbon cycle and climate: constraints from the 87Sr/86Sr isotopic ratio of seawater.

A numerical model describing the coupled evolution of the biogeochemical cycles of carbon, sulfur, calcium, magnesium, phosphorus, and strontium has been developed to describe the long-term changes of atmospheric carbon dioxide and climate during the Phanerozoic. The emphasis is on the effects of coupling the cycles of carbon and strontium. Various interpretations of the observed Phanerozoic history of the seawater 87Sr/86Sr ratio are investigated with the model. More specifically, the abilities of continental weathering, volcanism, and surface lithology in generating that signal are tested and compared. It is suggested that the observed fluctuations are mostly due to a changing weatherability over time. It is shown that such a conclusion is very important for the modelling of the carbon cycle. Indeed, it implies that the conventional belief that the evolution of atmospheric carbon dioxide and climate on a long time scale is governed by the balance between the volcanic input of CO2 and the rate of silicate weathering is not true. Rather carbon exchanges between the mantle and the exogenic system are likely to have played a key role too. Further, the increase of the global weathering rates with increasing surface temperature and/or atmospheric CO2 pressure usually postulated in long-term carbon cycle and climate modelling is also inconsistent with the new model. Other factors appear to have modulated the weatherability of the continents through time, such as mountain building and the existence of glaciers and ice sheets. Based on these observations, a history of atmospheric carbon dioxide and climate during Phanerozoic time, consistent with the strontium isotopic data, is reconstructed with the model and is shown to be compatible with paleoclimatic indicators, such as the timing of glaciation and the estimates of Cretaceous paleotemperatures.

Atmosphere↗

PubMed2006

Periparturient climatic, animal, and management factors influencing the incidence of milk Fever in grazing systems.

The objective of the present study was to quantify the climatic, animal, and management factors influencing incidence of milk fever (MF) in cows exposed to grazing systems. Data were extracted on 4,469 calvings of multiparous cows in a seasonal calving research herd between 1970 and 2000. Climatic data during the calving period also were extracted for these years. Poisson regression was used to investigate the effect of climate on frequency of MF within year; the offset variable was the number of cows at risk for MF at that time. Generalized estimating equations, with cow included as a repeated effect, were used to quantify the effect of parturition-associated cow and management factors on the logit of the probability of MF. Both univariate and multivariate analyses were performed. Explanatory variables investigated included time of calving relative to the herd-year calving period, parity, body weight, breed of cow, body condition score at calving, weight and gender of the calf, incidence of twin calves, calving inductions, and calving assistance. Odds of recurring MF within cow, as well as the timing of MF relative to day of calving, was quantified using generalized estimating equations with cow included as a repeated effect. Results show significant effects of evaporation, minimum grass temperature, difference between ambient maximum and minimum temperature, and rainfall on the odds of MF occurring, with a greater incidence at greater evaporation, larger diurnal variation in air temperature, greater rainfall, and lesser grass minimum temperature. Cow factors, such as age, excessive or poor body condition score, and requirement for calving assistance increased the odds of MF; a lesser odds ratio was observed in cows hormonally induced to calve and those that had twin births. Results indicate that herd managers may identify the day of greatest risk for MF and cows that are at greatest risk of MF based on climatic, cow, and management factors.

Animals↗

PubMed2006

Climatic factors and secondary sex ratio in dairy cows.

The hypothesis for this study was that the prevailing climate around the time of conception was associated with changes in the secondary sex ratio (SSR) in grazing, seasonally bred dairy cattle. Calving date, parity, cow breed, and calf sex were obtained for 8,621 lactations (with single births only) from 1,897 cows between 1970 and 2003 (inclusive). Conception date was estimated by subtracting a gestation length of 282 d from the date at calving. Climatic factors, including maximum and minimum ambient temperature, relative humidity, rainfall, sunlight hours, and evaporation rate, were averaged across the week immediately prior to conception for all lactations. Sun radiation data were available after 1976. Generalized estimating equations, with cow included as a repeated effect, were used to determine the effect of climate around the time of conception on the logit of the probability of a male calf. Breed of cow, year of conception, and parity at conception did not affect the SSR. The odds of a male calf being born were 3.74 times greater when the immediately previous calf born was male. A male calf was more likely to be born following periods of elevated air temperature, greater evaporation, or both. A 1 degrees C increase in average maximum air temperature from the average (18.3 degrees C), during the week immediately prior to conception, was associated with a 1-percentage unit increase in the probability of a male calf being born (i.e., from 52 to 53%). A corresponding 1 degrees C increase in average minimum air temperature was reflected in a 0.5-percentage unit increase in the probability of a male calf being born. The probability of a male calf being born increased by 2.9 percentage units with each additional millimeter of evaporation per day. Results indicate that climatic factors associated with elevated temperatures and greater evaporation may influence the SSR in dairy cattle.

Analysis of Variance↗

PubMed1988

Interactions of climatic factors affecting milk yield and composition.

Objectives were to evaluate effects of interactions of maximum temperature, minimum relative humidity, and solar radiation on milk yield and constituent traits. Effects of climate variables and their interactions were significant but small in most cases. Second order regression models were developed for several variables. Six were examined in detail: Holstein and Jersey milk yields, Holstein fat and Feulgen-DNA reflectance percent, and Jersey protein percent and yield. Maximum temperature had greatest influence on each response, followed by minimum relative humidity and solar radiation. Optimum conditions for milk production were at maximum temperatures below 19.4 degrees C, increasing solar radiation, and minimum relative humidity between 33.4 and 78.2% (cool sunny days, moderate humidity). Maximum Holstein fat percent of 3.5% was predicted for maximum temperatures below 30.8 degrees C, minimum relative humidity below 89%, and solar radiation below 109 Langleys; actual mean Holstein fat percent was 3.35%. Optimum climatic conditions for Jersey protein percent were at maximum temperature of 10.6 degrees C with solar radiation at 300 Langleys and relative humidity at 16% (cool sunny days, low humidity). Because noteworthy interactions existed between climate effects, response surface methodology was suitable for determining optimum climatic conditions for milk production.

Animals↗