Global change and the boreal forest: thresholds, shifting states or gradual change?

Changes in boreal climate of the magnitude projected for the 21st century have always caused vegetation changes large enough to be societally important. However, the rates and patterns of vegetation change are difficult to predict. We review evidence suggesting that these vegetation changes may be gradual at the northern forest limit or where seed dispersal limits species distribution. However, forest composition may be quite resilient to climate change in the central portions of a species range until some threshold is surpassed. At this point, changes can be rapid and unexpected, often causing a switch to very different ecosystem types. Many of these triggers for change are amenable to management, suggesting that our choice of policies in the coming decades will substantially influence the ecological and societal consequences of current climatic change.     

Impact of future climate changes on high pollution levels

Changes in climate variability as well as changes in extreme weather and climate events in the 20th century, especially those that took place during the last two to three decades of the 20th century, have been discussed in many recent scientific publications. Attempts to project the results of such studies in the future have been made under different assumptions. In this paper, we have chosen one of the well-known scenarios predicting changes of the climate in the world during the last 30 years of the 21st century. This scenario is used, together with several general predictions related to the future climate, to produce three climatic scenarios. The derived climatic scenarios are used to calculate predictions for future pollution levels in Denmark and in Europe by applying the Unified Danish Eulerian Model (UNI-DEM), on a space domain containing the whole of Europe.     

Challenges of climate change: an Arctic perspective

Climate change is being experienced particularly intensely in the Arctic. Arctic average temperature has risen at almost twice the rate as that of the rest of the world in the past few decades. Widespread melting of glaciers and sea ice and rising permafrost temperatures present additional evidence of strong Arctic warming. These changes in the Arctic provide an early indication of the environmental and societal significance of global consequences. The Arctic also provides important natural resources to the rest of the world (such as oil, gas, and fish) that will be affected by climate change, and the melting of Arctic glaciers is one of the factors contributing to sea level rise around the globe. An acceleration of these climatic trends is projected to occur during this century, due to ongoing increases in concentrations of greenhouse gases in the Earth's atmosphere. These Arctic changes will, in turn, impact the planet as a whole.     

Climate change impact on distribution and abundance of wildlife species: an analytical approach using GIS

An analytical approach to modelling the likely impact of climate change on the distribution and abundance of wildlife species is described using examples from Scotland. Data for present day distribution of wildlife and habitat are analysed using map data describing geographic variation in climatic factors. Climate data for the present day and under specified scenarios of change are themselves modelled within a GIS; climate modelling uses meteorological station data, climate change scenarios developed from GCMs and a variety of spatial interpolation techniques. The analytical procedure generates hypotheses defining ecological relationships between species distribution and climatic factors (monthly, seasonal and annual data). These relationships are then used to model the distribution of the species directly from climate and predict impacts of climate change. The analysis takes account of both direct impacts of climate on wildlife and indirect effects manifested through habitat response to climate change. The analytical procedure is implemented as a generic tool for inductive spatial analysis in GIS.     

Microrefugia: Not for everyone

Microrefugia are sites that support populations of species when their ranges contract during unfavorable climate episodes. Here, we review and discuss two aspects relevant for microrefugia. First, distributions of different species are influenced by different climatic variables. Second, climatic variables differ in the degree of local decoupling from the regional climate. Based on this, we suggest that only species limited by climatic conditions decoupled from the regional climate can benefit from microrefugia. We argue that this restriction has received little attention in spite of its importance for microrefugia as a mechanism for species resilience (the survival of unfavorable episodes and subsequent range expansion). Presence of microrefugia will depend on both the responses of individual species to local climatic variation and how climate-forcing factors shape the correlation between local and regional climate across space and time.     

Impact of Climate Change on Fish Population Dynamics in the Baltic Sea: A Dynamical Downscaling Investigation

Understanding how climate change, exploitation and eutrophication will affect populations and ecosystems of the Baltic Sea can be facilitated with models which realistically combine these forcings into common frameworks. Here, we evaluate sensitivity of fish recruitment and population dynamics to past and future environmental forcings provided by three ocean-biogeochemical models of the Baltic Sea. Modeled temperature explained nearly as much variability in reproductive success of sprat (Sprattus sprattus; Clupeidae) as measured temperatures during 1973-2005, and both the spawner biomass and the temperature have influenced recruitment for at least 50 years. The three Baltic Sea models estimate relatively similar developments (increases) in biomass and fishery yield during twenty-first century climate change (ca. 28 % range among models). However, this uncertainty is exceeded by the one associated with the fish population model, and by the source of global climate data used by regional models. Knowledge of processes and biases could reduce these uncertainties.     

Climate change and the adaptability of agriculture: a review

The assessment of climate change impacts on agriculture has emerged as a recognizable field of research over the past 15 years or so. In a relatively short period, this area of work has undergone a number of important conceptual and methodological developments. Among many questions that have been debated are the adaptability of agriculture to climate change and the importance of land management adjustments in reducing the adverse effects of climate change. In turn, this latter focus has spawned a discussion regarding the nature of adaptation and the ability of agriculture to respond to sudden and rapid climatic changes. In this paper we present an overview of this debate. It is argued that the first generation of climate change impact studies generally ignored the possibility that agriculturalists may adjust their farming practices in order to cope with climate change or to take advantage of new production opportunities. This conceptual oversight has been largely eliminated over the past five years or so. However, questions remain surrounding the likelihood that various adaptive strategies will actually be deployed in particular places. In this paper, we stress the importance of studying adaptation in the context of decision-making at the individual farm level and beyond.     

Economics of a global strategy for reduction of carbon emissions

The evolution of natural systems that feed and sustain human populations, and indeed the evolution of modern society, has occurred in the context of a moderate and stable climate. Therefore, recent trends in climate change, most likely caused by increasing concentrations of carbon dioxide and other radiative trace gases in the atmosphere, and the expected consequent global warming, are now a major concern. Carbon emissions from energy systems are considered one of the major contributors to climate change and are the focus of all studies on the prevention of climate changes and adaptation strategies. Two global energy scenarios (each with several options) are analysed in this paper: from a dynamic-as-usual concept to a more advanced concept with the goal of stabilising carbon dioxide concentrations in the atmosphere (equivalent to about a 60% reduction of carbon emission compared with today's level). It is shown that the stabilisation approach will require dramatic changes in energy systems: the share of non-carbon fuels will increase to about three quarters of the total primary energy consumption, which will itself grow by a factor of two by the middle of the next century. Surprisingly, the implementation costs turn out to be approximately the same for all scenarios (taking into account possible errors in the cost appraisals for several decades ahead). However, the cost distributions between energy production and use are quite different. Globally, these costs are 3-4% of the GNP, but for developing countries the share of energy investments is, on average, about 7-8% of the GNP, which is cause for concern and will greatly hamper economic and social progress in the Third World. The introduction of energy taxes or carbon taxes in developed countries and the raising of 'global energy funds' could help developing countries to overcome these difficulties. It is supposed that such a policy would stimulate economic growth in developing countries and, as a feedback, overlap the GNP losses in developed countries. The paper attempts to evaluate an optimal strategy for reducing carbon emissions for the next couple of decades, when large uncertainties surround global warming, and to show ways of establishing 'no-regret' policy.     

Fossil fuels in the 21st century

An overview of the importance of fossil fuels in supplying the energy requirements of the 21st century, their future supply, and the impact of their use on global climate is presented. Current and potential alternative energy sources are considered. It is concluded that even with substantial increases in energy derived from other sources, fossil fuels will remain a major energy source for much of the 21st century and the sequestration of CO2 will be an increasingly important requirement.     

Climate change: potential impact on plant diseases

Global climate has changed since pre-industrial times. Atmospheric CO(2), a major greenhouse gas, has increased by nearly 30% and temperature has risen by 0.3 to 0.6 degrees C. The intergovernmental panel on climate change predicts that with the current emission scenario, global mean temperature would rise between 0.9 and 3.5 degrees C by the year 2100. There are, however, many uncertainties that influence these predictions. Despite the significance of weather on plant diseases, comprehensive analysis of how climate change will influence plant diseases that impact primary production in agricultural systems is presently unavailable. Evaluation of the limited literature in this area suggests that the most likely impact of climate change will be felt in three areas: in losses from plant diseases, in the efficacy of disease management strategies and in the geographical distribution of plant diseases. Climate change could have positive, negative or no impact on individual plant diseases. More research is needed to obtain base-line information on different disease systems. Most plant disease models use different climatic variables and operate at a different spatial and temporal scale than do the global climate models. Improvements in methodology are necessary to realistically assess disease impacts at a global scale.     

Climate Change and the Adaptability of Agriculture: A Review

ABSTRACT

The assessment of climate change impacts on agriculture has emerged as a recognizable field of research over the past 15 years or so. In a relatively short period, this area of work has undergone a number of important conceptual and methodological developments. Among many questions that have been debated are the adaptability of agriculture to climate change and the importance of land management adjustments in reducing the adverse effects of climate change. In turn, this latter focus has spawned a discussion regarding the nature of adaptation and the ability of agriculture to respond to sudden and rapid climatic changes. In this paper we present an overview of this debate.

It is argued that the first generation of climate change impact studies generally ignored the possibility that agriculturalists may adjust their farming practices in order to cope with climate change or to take advantage of new production opportunities. This conceptual oversight has been largely eliminated over the past five years or so. However, questions remain surrounding the likelihood that various adaptive strategies will actually be deployed in particular places. In this paper, we stress the importance of studying adaptation in the context of decision-making at the individual farm level and beyond.     

Climate change and air pollution jointly creating nightmare for tourism industry

The objective of the study is to examine the long-run and causal relationship between climate change (i.e., greenhouse gas emissions, hydrofluorocarbons, per fluorocarbons, and sulfur hexafluoride), air pollution (i.e., methane emissions, nitrous oxide emissions, and carbon dioxide emissions), and tourism development indicators (i.e., international tourism receipts, international tourism expenditures, natural resource depletion, and net forest depletion) in the World’s largest regions. The aggregate data is used for robust analysis in the South Asia, the Middle East and North Africa, sub-Saharan Africa, and East Asia and the Pacific regions, over a period of 1975–2012. The results show that climatic factors and air pollution have a negative impact on tourism indicators in the form of deforestation and natural resource depletion. The impact is evident, as we have seen the systematic eroding of tourism industry, due to severe changes in climate and increasing strain of air pollution. There are several channels of cause–effect relationship between the climatic factors, air pollution, and tourism indicators in the World’s region. The study confirms the unidirectional, bidirectional, and causality independent relationship between climatic factors, air pollution, and tourism indicators in the World. It is conclusive that tourism industry is facing all time bigger challenges of reduce investment, less resources, and minor importance from the government agencies because of the two broad challenges, i.e., climate change and air pollution, putting them in a dismal state.     

Climate Change,Land Use Conflicts,Predation and Ecological Degradation as Challenges for Reindeer Husbandry in Northern Europe: What do We Really Know After Half a Century of Research?

Reindeer grazing has been entitled as ecological keystone in arctic-alpine landscapes. In addition, reindeer husbandry is tightly connected to the identity of the indigenous Sámi people in northern Europe. Nowadays, reindeer husbandry is challenged in several ways, of which pasture degradation, climate change, conflicting land uses and predation are the most important. Research on reindeer-related topics has been conducted for more than half a century and this review illuminates whether or not research is capable to match these challenges. Despite its high quality, traditional reindeer-related research is functionally isolated within the various disciplines. The meshwork of ecology, socio-economy, culture and politics, however, in which reindeer husbandry is embedded by various interactions, will remain unclear and difficult to manage, if actors and relationships are kept separate. We propose some targets for new integrative research approaches that incorporate traditional knowledge and focus on the entire human-ecological system 'reindeer husbandry' to develop solutions for its challenges.     

Effect of climate change on air quality

Air quality is strongly dependent on weather and is therefore sensitive to climate change. Recent studies have provided estimates of this climate effect through correlations of air quality with meteorological variables, perturbation analyses in chemical transport models (CTMs), and CTM simulations driven by general circulation model (GCM) simulations of 21st-century climate change. We review these different approaches and their results. The future climate is expected to be more stagnant, due to a weaker global circulation and a decreasing frequency of mid-latitude cyclones. The observed correlation between surface ozone and temperature in polluted regions points to a detrimental effect of warming. Coupled GCM–CTM studies find that climate change alone will increase summertime surface ozone in polluted regions by 1–10 ppb over the coming decades, with the largest effects in urban areas and during pollution episodes. This climate penalty means that stronger emission controls will be needed to meet a given air quality standard. Higher water vapor in the future climate is expected to decrease the ozone background, so that pollution and background ozone have opposite sensitivities to climate change. The effect of climate change on particulate matter (PM) is more complicated and uncertain than for ozone. Precipitation frequency and mixing depth are important driving factors but projections for these variables are often unreliable. GCM–CTM studies find that climate change will affect PM concentrations in polluted environments by ±0.1–1 μg m^?3 over the coming decades. Wildfires fueled by climate change could become an increasingly important PM source. Major issues that should be addressed in future research include the ability of GCMs to simulate regional air pollution meteorology and its sensitivity to climate change, the response of natural emissions to climate change, and the atmospheric chemistry of isoprene. Research needs to be undertaken on the effect of climate change on mercury, particularly in view of the potential for a large increase in mercury soil emissions driven by increased respiration in boreal ecosystems.     

Increase in summer European ozone amounts due to climate change

The local and regional distribution of pollutants is significantly influenced by weather patterns and variability along with the spatial patterns of emissions. Therefore, climatic changes which affect local meteorological conditions can alter air quality. We use the regional air quality model CHIMERE driven by meteorological fields from regional climate change simulations to investigate changes in summer ozone mixing ratios over Europe under increased greenhouse gas (GHG) forcing. Using three 30-year simulation periods, we find that daily peak ozone amounts as well as average ozone concentrations substantially increase during summer in future climate conditions. This is mostly due to higher temperatures and reduced cloudiness and precipitation over Europe and it leads to a higher number of ozone events exceeding information and warning thresholds. Our results show a pronounced regional variability, with the largest effects of climate change on ozone concentrations occurring over England, Belgium, Germany and France. The temperature-driven increase in biogenic emissions appears to enhance the ozone production and isoprene was identified as the most important chemical factor in the ozone sensitivity. We also find that summer ozone levels in future climate projections are similar to those found during the exceptionally warm and dry European summer of 2003. Our simulations suggest that in future climate conditions summer ozone might pose a much more serious threat to human health, agriculture and natural ecosystems in Europe, so that the effects of climate trends on pollutant amounts should be considered in future emission control measures.     

Climatic sensitivity of temperate forests

Climatic change and associated global changes are of major interest to foresters, both in terms of forest ecology and of future forest production. Predicting the likely effects of global change on forests is extremely difficult due to the critical lack of information on regional changes in meteorological factors relevant to forests. However, existing models of forest production and forest distribution fail to take adequate account of what is already known. Climate and carbon dioxide concentrations have shown substantial changes over the last 100 years. Although the rate of change is likely to increase, recent proposed and implemented control strategies, together with better climatic models, are tending to suggest that the rate of change will be less than initially thought. This means that past changes may provide an increasingly useful source of information. In particular, information on the impact on forests of both long-term climate change and short-term climatic events is rapidly increasing. Such information should be built into future forest response models.     

Global climate change: The quantifiable sustainability challenge

Population growth and the pressures spawned by increasing demands for energy and resource-intensive goods, foods, and services are driving unsustainable growth in greenhouse gas (GHG) emissions. Recent GHG emission trends are consistent with worst-case scenarios of the previous decade. Dramatic and near-term emission reductions likely will be needed to ameliorate the potential deleterious impacts of climate change. To achieve such reductions, fundamental changes are required in the way that energy is generated and used. New technologies must be developed and deployed at a rapid rate. Advances in carbon capture and storage, renewable, nuclear, and transportation technologies are particularly important; however, global research and development efforts related to these technologies currently appear to fall short relative to needs. Even with a proactive and international mitigation effort, humanity will need to adapt to climate change, but the adaptation needs and damages will be far greater if mitigation activities are not pursued in earnest. In this review, research is highlighted that indicates increasing global and regional temperatures and ties climate changes to increasing GHG emissions. GHG mitigation targets necessary for limiting future global temperature increases are discussed, including how factors such as population growth and the growing energy intensity of the developing world will make these reduction targets more challenging. Potential technological pathways for meeting emission reduction targets are examined, barriers are discussed, and global and U.S. modeling results are presented that suggest that the necessary pathways will require radically transformed electric and mobile sectors. While geoengineering options have been proposed to allow more time for serious emission reductions, these measures are at the conceptual stage with many unanswered cost, environmental, and political issues.

Implications:?This paper lays out the case that mitigating the potential for catastrophic climate change will be a monumental challenge, requiring the global community to transform its energy system in an aggressive, coordinated, and timely manner. If this challenge is to be met, new technologies will have to be developed and deployed at a rapid rate. Advances in carbon capture and storage, renewable, nuclear, and transportation technologies are particularly important. Even with an aggressive international mitigation effort, humanity will still need to adapt to significant climate change.     

Hydroclimatic changes and drivers in the Sava River Catchment and comparison with Swedish catchments

In this study, we investigate long-term hydroclimatic changes and their possible relation to regional changes in climate, land-use and water-use over the twentieth century in the transboundary Sava River Catchment (SRC) in South Eastern Europe. In a hydropower dominated part of the SRC, unlike in an unregulated part, we find increase in average annual evapotranspiration and decrease in temporal runoff variability, which are not readily explainable by observed concurrent climate change in temperature and precipitation and may be more related to landscape-internal change drivers. Among the latter investigated here, results indicate hydropower developments as most closely related to the found hydroclimatic shifts, consistent with previous such indications in studies of Swedish hydropower catchments. Overall, the present results have quantitatively framed the recent history and present state of hydroclimate in the SRC, of relevance for water resources in several countries and for a majority of their populations. This provides a useful basis for further assessment of possible future hydroclimatic changes, under different scenarios of climate change and land/water-use developments in the region.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0641-0) contains supplementary material, which is available to authorized users.     

Global climate change in the instrumental period

The instrumental period of climate history began in the 18th century with the commencement of routine weather observations at fixed sites. Estimates of global-mean climate (e.g. temperature and precipitation) were not possible, however, until the establishment of extensive observing networks midway through the 19th century. This paper reviews our knowledge of global climate change in the instrumental period. Time series of global-mean temperature and precipitation are examined and a comparison is made between two independent 30-year climatologies: 1931-1960 and 1961-1990. Examples are also provided of regional-scale climate changes. Such assessments are important for two reasons. First, they establish the variability of climate on the time-scale of decades, time-scales upon which it is reasonable to plan economic and socio-political activities. Second, and more specifically, they enable us to quantify the magnitude of global-mean climate change which has occurred over this period. Such detailed diagnostic climate information is a necessary, although not sufficient, prerequisite for the detection of global-scale warming which may have occurred due to the enhanced greenhouse effect. Some attention is given to explanations of the observed changes in global-mean climate.