Climate change. A single climate mover for Antarctica.
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That we are in a period of extraordinary rates of climate change is today evident. These climate changes are likely to impact local weather conditions with direct impacts on precipitation patterns and urban drainage. In recent years several studies have focused on revealing the nature, extent and consequences of climate change on urban drainage and urban runoff pollution issues. This study uses predictions from a regional climate model to look at the effects of climate change on extreme precipitation events. Results are presented in terms of point rainfall extremes. The analysis involves three steps: Firstly, hourly rainfall intensities from 16 point rain gauges are averaged to create a rain gauge equivalent intensity for a 25 x 25 km square corresponding to one grid cell in the climate model. Secondly, the differences between present and future in the climate model is used to project the hourly extreme statistics of the rain gauge surface into the future. Thirdly, the future extremes of the square surface area are downscaled to give point rainfall extremes of the future. The results and conclusions rely heavily on the regional model's suitability in describing extremes at timescales relevant to urban drainage. However, in spite of these uncertainties, and others raised in the discussion, the tendency is clear: extreme precipitation events effecting urban drainage and causing flooding will become more frequent as a result of climate change.
Climate change would have a range of impacts on human health. Health impacts would be caused by the direct effect of climatic factors on human health, such as heat stress, and possible changes in the frequency and intensity of extreme weather events such as storms, floods and droughts. Impacts on health would also be mediated by the indirect effects of climate change, such as changes in availability of food and water and the distribution of vector-borne diseases. The majority of health impacts would be adverse and would depend greatly on the vulnerability of populations.
Human activities are resulting in increases in atmospheric greenhouse gases, such as carbon dioxide, and changes in global climate. These, in turn, are likely to have had, and will continue to have, impacts on human health. While such impacts have received increasing attention in recent years, the impacts of climate change on aeroallergens and related allergic diseases have been somewhat neglected. Despite this, a number of studies have revealed potential impacts of climate change on aeroallergens that may have enormous clinical and public health significance. The purpose of this review is to synthesize this work and to outline a number of research challenges in this area. There is now considerable evidence to suggest that climate change will have, and has already had, impacts on aeroallergens. These include impacts on pollen amount, pollen allergenicity, pollen season, plant and pollen distribution, and other plant attributes. There is also some evidence of impacts on other aeroallergens, such as mould spores. There are many research challenges along the road to a more complete understanding of the impacts of climate change on aeroallergens and allergic diseases such as asthma and hayfever. It is important that public health authorities and allergy practitioners be aware of these changes in the environment, and that research scientists embrace the challenges that face further work in this area.
Climate change is expected to alter the distribution and abundance of many species. Predictions of climate-induced population extinctions are supported by geographic range shifts that correspond to climatic warming, but few extinctions have been linked mechanistically to climate change. Here we show that extinctions of two populations of a checkerspot butterfly were hastened by increasing variability in precipitation, a phenomenon predicted by global climate models. We model checkerspot populations to show that changes in precipitation amplified population fluctuations, leading to rapid extinctions. As populations of checkerspots and other species become further isolated by habitat loss, climate change is likely to cause more extinctions, threatening both species diversity and critical ecosystem services.
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We study the interactions between the geochemical cycles of carbon and long-term changes in climate. Climate change is studied with a simple, zonally averaged energy balance climate model that includes the greenhouse effect of carbon dioxide explicitly. The geochemical model balances the rate of consumption of carbon dioxide in silicate weathering against its release by volcanic and metamorphic processes. The silicate weathering rate is expressed locally as a function of temperature, carbon dioxide partial pressure, and runoff. The global weathering rate is calculated by integrating these quantities over the land area as a function of latitude. Carbon dioxide feedback stabilizes the climate system against a reduction in solar luminosity and may contribute to the preservation of equable climate on the early Earth, when solar luminosity was low. The system responds to reduced land area by increasing carbon dioxide partial pressure and warming the globe. Our model makes it possible to study the response of the system to changing latitudinal distribution of the continents. A concentration of land area at high latitudes leads to high carbon dioxide partial pressures and high global average temperature because weathering of high-latitude continents is slow. Conversely, concentration of the continents at low latitudes yields a cold globe and ice at low latitudes, a situation that appears to be representative of the late Precambrian glacial episode. This model is stable against ice albedo catastrophe even when the ice line occurs at low latitudes. In this it differs from energy balance models that lack the coupling to the geochemical cycle of carbon.
In this paper the scientific challenges of observing, modelling, understanding and predicting rapid changes in climate are discussed, with a specific focus on the role of the Atlantic thermohaline circulation. The palaeo and present-day observational and modelling studies being carried out to meet these challenges, under the aegis of a new NERC Rapid Climate Change thematic programme (RAPID), are outlined. In particular, the paper describes the work being done to monitor changes in the meridional overturning circulation of the North Atlantic. The paper concludes with some speculative comments about potential mechanisms for rapid changes.
There is near unanimous scientific consensus that greenhouse gas emissions generated by human activity will change Earth's climate. The recent (globally averaged) warming by 0.5 degrees C is partly attributable to such anthropogenic emissions. Climate change will affect human health in many ways-mostly adversely. Here, we summarise the epidemiological evidence of how climate variations and trends affect various health outcomes. We assess the little evidence there is that recent global warming has already affected some health outcomes. We review the published estimates of future health effects of climate change over coming decades. Research so far has mostly focused on thermal stress, extreme weather events, and infectious diseases, with some attention to estimates of future regional food yields and hunger prevalence. An emerging broader approach addresses a wider spectrum of health risks due to the social, demographic, and economic disruptions of climate change. Evidence and anticipation of adverse health effects will strengthen the case for pre-emptive policies, and will also guide priorities for planned adaptive strategies.
Large, abrupt, and widespread climate changes with major impacts have occurred repeatedly in the past, when the Earth system was forced across thresholds. Although abrupt climate changes can occur for many reasons, it is conceivable that human forcing of climate change is increasing the probability of large, abrupt events. Were such an event to recur, the economic and ecological impacts could be large and potentially serious. Unpredictability exhibited near climate thresholds in simple models shows that some uncertainty will always be associated with projections. In light of these uncertainties, policy-makers should consider expanding research into abrupt climate change, improving monitoring systems, and taking actions designed to enhance the adaptability and resilience of ecosystems and economies.
Climate change has led to shifts in phenology in many species distributed widely across taxonomic groups. It is, however, unclear how we should interpret these shifts without some sort of a yardstick: a measure that will reflect how much a species should be shifting to match the change in its environment caused by climate change. Here, we assume that the shift in the phenology of a species' food abundance is, by a first approximation, an appropriate yardstick. We review the few examples that are available, ranging from birds to marine plankton. In almost all of these examples, the phenology of the focal species shifts either too little (five out of 11) or too much (three out of 11) compared to the yardstick. Thus, many species are becoming mistimed due to climate change. We urge researchers with long-term datasets on phenology to link their data with those that may serve as a yardstick, because documentation of the incidence of climate change-induced mistiming is crucial in assessing the impact of global climate change on the natural world.
Climate change is expected to have important impacts on aquatic ecosystems. On the Boreal Shield, mean annual air temperatures are expected to increase 2 to 4 degrees C over the next 50 years. An important challenge is to predict how changes in climate and climate variability will impact natural systems so that sustainable management policies can be implemented. To predict responses to complex ecosystem changes associated with climate change, we used long-term biotic databases to evaluate how important elements of the biota in Boreal Shield lakes have responded to past fluctuations in climate. Our long-term records span a two decade period where there have been unusually cold years and unusually warm years. We used coherence analyses to test for regionally operating controls on climate, water temperature, pH, and plankton richness and abundance in three regions across Ontario: the Experimental Lakes Area, Sudbury, and Dorset. Inter-annual variation in air temperature was similar among regions, but there was a weak relationship among regions for precipitation. While air temperature was closely related to lake surface temperatures in each of the regions, there were weak relationships between lake surface temperature and richness or abundance of the plankton. However, inter-annual changes in lake chemistry (i.e., pH) were correlated with some biotic variables. In some lakes in Sudbury and Dorset, pH was dependent on extreme events. For example, El Nino related droughts resulted in acidification pulses in some lakes that influenced phytoplankton and zooplankton richness. These results suggest that there can be strong heterogeneity in lake ecosystem responses within and across regions.
The spread of exotic species and climate change are among the most serious global environmental threats. Each independently causes considerable ecological damage, yet few data are available to assess whether changing climate might facilitate invasions by favoring introduced over native species. Here, we compare our long-term record of weekly sessile marine invertebrate recruitment with interannual variation in water temperature to assess the likely effect of climate change on the success and spread of introduced species. For the three most abundant introduced species of ascidian (sea squirt), the timing of the initiation of recruitment was strongly negatively correlated with winter water temperature, indicating that invaders arrived earlier in the season in years with warmer winters. Total recruitment of introduced species during the following summer also was positively correlated with winter water temperature. In contrast, the magnitude of native ascidian recruitment was negatively correlated with winter temperature (more recruitment in colder years) and the timing of native recruitment was unaffected. In manipulative laboratory experiments, two introduced compound ascidians grew faster than a native species, but only at temperatures near the maximum observed in summer. These data suggest that the greatest effects of climate change on biotic communities may be due to changing maximum and minimum temperatures rather than annual means. By giving introduced species an earlier start, and increasing the magnitude of their growth and recruitment relative to natives, global warming may facilitate a shift to dominance by nonnative species, accelerating the homogenization of the global biota.
Human activity has contributed to climate change. The relationship between climate and child health has not been well investigated. This review discusses the role of climate change on child health and suggests 3 ways in which this relationship may manifest. First, environmental changes associated with anthropogenic greenhouse gases can lead to respiratory diseases, sunburn, melanoma, and immunosuppression. Second, climate change may directly cause heat stroke, drowning, gastrointestinal diseases, and psychosocial maldevelopment. Third, ecologic alterations triggered by climate change can increase rates of malnutrition, allergies and exposure to mycotoxins, vector-borne diseases (malaria, dengue, encephalitides, Lyme disease), and emerging infectious diseases. Further climate change is likely, given global industrial and political realities. Proactive and preventive physician action, research focused on the differential effects of climate change on subpopulations including children, and policy advocacy on the individual and federal levels could contain climate change and inform appropriate prevention and response.
A major component of climate change is a manifestation of changes in air quality. This paper explores the question of air quality from the climate change modelling perspective. It reviews recent research advances on the cause-effect relationships between atmospheric air composition and climate change, primarily based on the Intergovernmental Panel on Climate Change (IPCC) assessment of climate change over the past decade. There is a growing degree of confidence that the warming world over the past century was caused by human-related changes in the composition of air. Reliability of projections of future climate change is highly dependent on future emission scenarios that have been identified that in turn depend on a multitude of complicated interacting social-economic factors. Anticipated improvements in the performance of climate models is a major source of optimism for better climate projections in the future, but the real benefits of its contribution will be closely coupled with other sources of uncertainty, and in particular emission projections.
This paper considers the potential impact on human health from waterborne and vector-borne infections. It concentrates on the impact of two possible changes to climate; increased frequency of heavy rainfall events, with associated flooding and increased temperature. Flooding is associated with increased risk of infection in developing nations but not in the West unless water sources are compromised. There have been numerous reported of outbreaks that followed flooding that led to contamination of underground sources of drinking water. Heavy rainfall also leads to deterioration in the quality of surface waters that could adversely affect the health of those engaged in recreational water contact. It is also concluded that there may be an increase in the number of cyanobacterial blooms because of a combination of increased nutrient concentrations and water temperature. It is considered unlikely that climate change will lead to an increase in disease linked to mains drinking water, although private supplies would be at risk from increased heavy rainfall events. Although increased temperature could lead to climatic conditions favourable to increases in certain vector-borne diseases such as malaria, the infrastructure in the UK would prevent the indigenous spread of malaria.
Climate policy decisions driving future greenhouse gas mitigation efforts will strongly influence the success of compliance with Article 2 of the United Nations Framework Convention on Climate Change, the prevention of "dangerous anthropogenic interference (DAI) with the climate system." However, success will be measured in very different ways by different stakeholders, suggesting a spectrum of possible definitions for DAI. The likelihood of avoiding a given threshold for DAI depends in part on uncertainty in the climate system, notably, the range of uncertainty in climate sensitivity. We combine a set of probabilistic global average temperature metrics for DAI with probability distributions of future climate change produced from a combination of several published climate sensitivity distributions and a range of proposed concentration stabilization profiles differing in both stabilization level and approach trajectory, including overshoot profiles. These analyses present a "likelihood framework" to differentiate future emissions pathways with regard to their potential for preventing DAI. Our analysis of overshoot profiles in comparison with non-overshoot profiles demonstrates that overshoot of a given stabilization target can significantly increase the likelihood of exceeding "dangerous" climate impact thresholds, even though equilibrium warming in our model is identical for non-overshoot concentration stabilization profiles having the same target.
Understanding how climate change will affect the planet is a key issue worldwide. Questions concerning the pace and impacts of climate change are thus central to many ecological and biogeochemical studies, and addressing the consequences of climate change is now high on the list of priorities for funding agencies. Here, we review the interactions between climate change and plankton communities, focusing on systematic changes in plankton community structure, abundance, distribution and phenology over recent decades. We examine the potential socioeconomic impacts of these plankton changes, such as the effects of bottom-up forcing on commercially exploited fish stocks (i.e. plankton as food for fish). We also consider the crucial roles that plankton might have in dictating the future pace of climate change via feedback mechanisms responding to elevated atmospheric CO(2) levels. An important message emerges from this review: ongoing plankton monitoring programmes worldwide will act as sentinels to identify future changes in marine ecosystems.