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The present-day arctic flora replaced Arcto-Tertiary forest when global temperatures dropped markedly towards the end of the Pliocene 3-4 million years ago. During the Quaternary (from 1.8 mya) recurrent cycles of ice ages (glaciations) interspersed with shorter warmer periods (interglacials) have caused arctic and alpine plants to experience frequent range fragmentations and expansions. The application of molecular phylogenetic and phylogeographic analysis, along with an accumulating body of pollen and macrofossil evidence, is providing a greater understanding of the nature and effects of these events. To report what is new in this regard and also to assess what changes might lie ahead as a result of rapid climate warming, a Botanical Society of Scotland Symposium was held in June 2007 at the University of St Andrews on the History, evolution and future of arctic and alpine flora. This special issue contains papers based on presentations given at this meeting. Its aim is to highlight the fusion of recent fossil, molecular and ecological evidence that has advanced our understanding of events that moulded the origin and composition of arctic and alpine floras. In addition, a brief assessment is made of the future of these floras in a rapidly warming world. [ABSTRACT FROM AUTHOR]

Long-term trends in Arctic sea ice are of particular interest in studies of global temperature, climate change, and industrial application. This paper analyzes intra-annual and interannual trends in Ku-band backscatter over first-year (FY) and multiyear (MY) sea ice to develop a new sea-ice-type classification method. Histograms of backscatter are derived from high-resolution backscatter images created using the scatterometer image reconstruction (SIR) algorithm applied to measurements obtained by the SeaWinds instrument aboard QuikSCAT. The backscatter of FY and MY sea ice are clearly identifiable and are observed to vary seasonally. Using an average of the annual backscatter trends obtained from QuikSCAT, a classification of MY ice is obtained, which uses a time-dependent threshold value. Validation of the classification method is done using regional ice charts from the Canadian Ice Service. Differences in ice classification are found to be less than 6\% for the winters of 2006–2007 and 2007–2008, and the end of 2008. Anomalies in the distribution of sea ice backscatter from year to year suggest a reduction in MY ice cover between 2003 and 2009 and an approximately equivalent increase in FY ice cover. [ABSTRACT FROM PUBLISHER]

This paper suggests that the Polar Regions are excellent places for thinking about historical interactions between climate change, science, and politics from the beginning of the Cold War up to the present. Since the second half of the 1940s, science has played a central role in contesting claims to political authority in both the Arctic and the Antarctic. Research conducted in the Polar Regions has made a major contribution to the science of climate change on a global scale, and research agendas have been closely connected in the two regions. Viewed from a comparative perspective, however, the historical experiences of global warming in the Arctic and Antarctica have been quite different. Climate research has suggested that warming is generally happening faster over much of the Arctic than the Antarctic. In addition, the recent histories of the two regions show that climate change in the Arctic is destabilizing politics there, whereas in Antarctica climate change is helping to reinforce the existing political structures framed by the Antarctic Treaty System (ATS). A comparative approach to the history of climate change in the Polar Regions helps to demonstrate that science, politics, and environmental change have each played important roles without making any single factor deterministic. WIREs Clim Change 2012, 3:145-159. doi: 10.1002/wcc.161 For further resources related to this article, please visit the . [ABSTRACT FROM AUTHOR]

Recent scientific findings, as presented in the Arctic Climate Impact Assessment (AdA), indicate that climate change in the Arctic is happening now, at a faster rate than elsewhere in the world, and with major implications for peoples of the Arctic (especially indigenous peoples) and the rest of the planet. This paper examines scientific and political representations of Arctic indigenous peoples that have been central to the production and articulation of these claims. ACIA employs novel forms and strategies of representation that reflect changing conceptual models and practices of global change science and depict indigenous peoples as expert, exotic, and at-risk. These portrayals emerge alongside the growing political activism of Arctic indigenous peoples who present themselves as representatives or embodiments of climate change itself as they advocate for climate change mitigation policies. These mutually constitutive forms of representation suggest that scientific ways of seeing the global environment shape and are shaped by the public image and voice of global citizens. Likewise, the authority, credibility, and visibility of Arctic indigenous activists derive, in part, from their status as at-risk experts, a status buttressed by new scientific frameworks and methods that recognize and rely on the local experiences and knowledges of indigenous peoples. Analyses of these relationships linking scientific and political representations of Arctic climate change build upon science and technology studies (STS) scholarship on visualization, challenge conventional notions of globalization, and raise questions about power and accountability in global climate change research. [ABSTRACT FROM AUTHOR]

Climate change is already occurring in the Arctic and the Arctic Climate Impact Assessment recently concluded that future climate change could be devastating for Inuit. This paper characterises vulnerability to climate change in two Inuit communities in the Canadian territory of Nunavut, focusing on the resource harvesting sector. In both communities, Inuit have demonstrated significant adaptability in the face of current changes in climatic conditions. This adaptability is facilitated by traditional Inuit knowledge, strong social networks, flexibility in resource use, and institutional support. Changing Inuit livelihoods, however, have undermined certain aspects of adaptive capacity and have resulted in emerging vulnerabilities. Global and regional climate projections indicate that climatic conditions which currently pose risks are expected to be negatively affected by future climate change. These projections are not without precedent and analysis of current vulnerability and identification of adaptation constraints by Inuit in the two communities indicate the continued importance of traditional coping mechanisms. The ability to draw on these coping mechanisms in light of future climate change, however, will be unequal and the research indicates that young Inuit and those without access to economic resources, in particular, are vulnerable. [ABSTRACT FROM AUTHOR]

The climate change projections of the Intergovernmental Panel on Climate Change are based on scenarios for future emissions, but these are not statistically-based and do not have a full probabilistic interpretation. Raftery et al. (Nat Clim Change 7:637–641, 2017) and Liu and Raftery (Commun Earth Environ 2:1–10, 2021) developed probabilistic forecasts for global average temperature change to 2100, but these do not give forecasts for specific parts of the globe. Here we develop a method for probabilistic long-term spatial forecasts of local average annual temperature change, combining the probabilistic global method with a pattern scaling approach. This yields a probability distribution for temperature in any year and any part of the globe in the future. Out-of-sample predictive validation experiments show the method to be well calibrated. Consistent with previous studies, we find that for long-term temperature changes, high latitudes warm more than low latitudes, continents more than oceans, and the Northern Hemisphere more than the Southern Hemisphere, except for the North Atlantic. There is a 5% chance that the temperature change for the Arctic would reach 16 ∘ C. With probability 95%, the temperature of North Africa, West Asia and most of Europe will increase by at least 2 ∘ C. We find that natural variability is a large part of the uncertainty in early years, but this declines so that by 2100 most of the overall uncertainty comes from model uncertainty and uncertainty about future emissions. [ABSTRACT FROM AUTHOR]

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The article presents a paper that discusses increase in global warming in the Arctic Region twice as fast as compared to other regions on the Earth. It informs that some of the scientists suggest Arctic amplification as one of the reason for the increase that can alter atmospheric circulation patterns and effect weather in the U.S., Europe and Asia. It also presents views of climatologist Dim Coumou at the Potsdam Institute for Climate Impact Research in Germany.

Sea ice is influential in regulating energy exchanges between the ocean and the atmosphere, and has figured prominently in scientific studies of climate change and climate feedbacks. However, sea ice is also a vital component of everyday life in Inuit communities of the circumpolar Arctic. Therefore, it is important to understand the links between the potential impacts of climate change on Arctic sea ice extent, distribution, and thickness as well as the related consequences for northern coastal populations. This paper explores the relationship between sea ice and climate change from both scientific and Inuit perspectives. Based on an overview of diverse literature the experiences, methods, and goals which differentiate local and scientific sea ice knowledge are examined. These efforts are considered essential background upon which to develop more accurate assessments of community vulnerability to climate, and resulting sea ice, change. Inuit and scientific perspectives may indeed be the ideal complement when investigating the links between sea ice and climate change, but effective and appropriate conceptual bridges need to be built between the two types of expertise. The complementary nature of these knowledge systems may only be realized, in a practical sense, if significant effort is expended to: (i) understand sea ice from both Inuit and scientific perspectives, along with their underlying differences; (ii) investigate common interests or concerns; (iii) establish meaningful and reciprocal research partnerships with Inuit communities; (iv) engage in, and improve, collaborative research methods; and, (v) maintain ongoing dialogue. [ABSTRACT FROM AUTHOR]

The Arctic is experiencing rapid climate change in response to changes in greenhouse gases, aerosols, and other climate drivers. Emission changes in general, as well as geographical shifts in emissions and transport pathways of short‐lived climate forcers, make it necessary to understand the influence of each climate driver on the Arctic. In the Precipitation Driver Response Model Intercomparison Project, 10 global climate models perturbed five different climate drivers separately (CO2, CH4, the solar constant, black carbon, and SO4). We show that the annual mean Arctic amplification (defined as the ratio between Arctic and the global mean temperature change) at the surface is similar between climate drivers, ranging from 1.9 (± an intermodel standard deviation of 0.4) for the solar to 2.3 (±0.6) for the SO4 perturbations, with minimum amplification in the summer for all drivers. The vertical and seasonal temperature response patterns indicate that the Arctic is warmed through similar mechanisms for all climate drivers except black carbon. For all drivers, the precipitation change per degree global temperature change is positive in the Arctic, with a seasonality following that of the Arctic amplification. We find indications that SO4 perturbations produce a slightly stronger precipitation response than the other drivers, particularly compared to CO2. Key Points: Arctic amplification of surface warming is similar between global drivers of climate changeBlack carbon induces differing vertical and seasonal amplification patternsSulfate affects Arctic precipitation responses more strongly than other drivers, particularly in the summer season [ABSTRACT FROM AUTHOR]

Temperatures were examined at 118 stations located in the Arctic and compared to observations at 50 European stations whose records averaged 200 years and in a few cases extend to the early 1700s. Nearly all stations exhibited warming trends. For each station, the temperature relative to the average value during 1961-1990 was found. The resulting temperature change averaged over the Arctic stations was plotted. For the period 1820-2014, trends were found for the January, July and annual temperatures of 1.0, 0.0 and 0.7 °C per century, respectively. Decadal variations are evident and much of the temperature increase occurred during the 1990s. Over the past century, Siberia, Alaska and Western Canada have experienced somewhat greater warming than Eastern Canada, Greenland and Northern Europe. The temperature change experienced by the Arctic stations during the last two centuries closely tracks that found for the European stations. [ABSTRACT FROM AUTHOR]

Arctic warming has sparked a growing interest because of its possible impacts on mid-latitude climate. A number of unusually harsh cold winters have occurred in many parts of East Asia and North America in the past few years, and observational and modelling studies have suggested that atmospheric variability linked to Arctic warming might have played a central role. Here we identify two distinct influences of Arctic warming which may lead to cold winters over East Asia or North America, based on observational analyses and extensive climate model results. We find that severe winters across East Asia are associated with anomalous warmth in the Barents-Kara Sea region, whereas severe winters over North America are related to anomalous warmth in the East Siberian-Chukchi Sea region. Each regional warming over the Arctic Ocean is accompanied by the local development of an anomalous anticyclone and the downstream development of a mid-latitude trough. The resulting northerly flow of cold air provides favourable conditions for severe winters in East Asia or North America. These links between Arctic and mid-latitude weather are also robustly found in idealized climate model experiments and CMIP5 multi-model simulations. We suggest that our results may help improve seasonal prediction of winter weather and extreme events in these regions. [ABSTRACT FROM AUTHOR]

The role of tourism in local development, combined with globalisation and climate change, are generating both opportunities and threats across Arctic communities. The impacts of climate change are felt more intensely in communities that are dependent on natural resources. This is increasingly occurring through Arctic tourism, which is often based on nature, and is the foundation of the economy of many small Arctic communities. The interplay between tourism and community-based adaptation represents a significant focus in Arctic tourism studies and can bring invaluable information to governments about the local level climate change impacts on livelihoods and on the potential future challenges. The results from a vulnerability study conducted in two case study communities in Finnish Lapland indicate that both external and internal stresses, combined with the impacts of climate change, force the communities to reconsider their current development paths. The communities are still able to absorb the changes taking place in weather patterns, but the current development paths do not fully support the idea of sustainable adaptation, with its concepts of environmental integrity, social justice and participation. Though several adaptation strategies are deployed, future vulnerability may increase due to ineffective adaptation mechanisms and the increasing role of nature in tourism development. [ABSTRACT FROM AUTHOR]

The Arctic is opening. Global warming is leading to seasonal sea-ice retreat, which in turn opens hitherto impassable shipping routes and new areas for resource exploitation. Such changes are elevating the Arctic's geostrategic value and stoking inter-state competition. The admission of five Asian states as Arctic Council observers in 2013 underlines the increased importance of the High North in global politics. And as the sea ice retreats, so military forces are redeployed northwards, raising the prospect of conflict. Christian Le Mière and Jeffrey Mazo bring much-needed sobriety to the discussion of change in the Arctic, outlining the possibilities of and limits to economic opportunities in the High North while providing a detailed examination of the political and military changes this might bring. Their analysis provides an invaluable guide as the region transforms from a parochial concern to a global interest. [ABSTRACT FROM AUTHOR]

Climate change incurs costs, but government adaptation budgets are limited. Beyond a certain point, individuals must bear the costs or adapt to new circumstances, creating political-economic tipping points that we explore in three examples. First, many Alaska Native villages are threatened by erosion, but relocation is expensive. To date, critically threatened villages have not yet been relocated, suggesting that we may already have reached a political-economic tipping point. Second, forest fires shape landscape and ecological characteristics in interior Alaska. Climate-driven changes in fire regime require increased fire-fighting resources to maintain current patterns of vegetation and land use, but these resources appear to be less and less available, indicating an approaching tipping point. Third, rapid sea level rise, for example from accelerated melting of the Greenland ice sheet, will create a choice between protection and abandonment for coastal regions throughout the world, a potential global tipping point comparable to those now faced by Arctic communities. The examples illustrate the basic idea that if costs of response increase more quickly than available resources, then society has fewer and fewer options as time passes. [ABSTRACT FROM AUTHOR]

Temperature change is acknowledged to have a significant effect on soil biological processes and the corresponding sequestration of carbon and cycling of nutrients. Soils at high latitudes are likely to be particularly impacted by increases in temperature. Icelandic soils experience unusually frequent freeze and thaw cycles compare to other Arctic regions, which are increasing due to a warming climate. As a consequence these soils are frequently affected by short term temperature fluctuations. In this study, the short term response of a range of soil microbial parameters (respiration, nutrient availability, microbial biomass carbon, arylphosphatase and dehydrogenase activity) to temperature changes was measured in sub-arctic soils collected from across Iceland. Sample sites reflected two soil temperature regimes (cryic and frigid) and two land uses (pasture and arable). The soils were sampled from the field frozen, equilibrated at -20 °C and then incubated for two weeks at -10 °C, °2 °C, +2 °C and +10°. Respiration and enzymatic activity were temperature dependent. The soil temperature regime affected the soil microbial biomass carbon sensitivity to temperatures. When soils where sampled from the cryic temperature regime a decreasing soil microbial biomass was detected when temperatures rose above the freezing point. Frigid soils, sampled from milder climatic conditions, where unaffected by difference in temperatures. Nitrogen mineralisation did not change with temperature. At -10 °C, dissolved organic carbon accounted for 88% of the fraction of labile carbon which was significantly greater than that recorded at +10 °C when dissolved organic carbon accounted for as low as 42% of the labile carbon fraction. [ABSTRACT FROM AUTHOR]

One of the reported changes of arctic ecosystems in response to warming climate is the advance of the leaf appearance in spring. Such phenological changes play a role in the structural changes within tundra ecosystem communities. Recently, we developed a model that estimates the leaf appearance date for deciduous trees in taiga. We apply this model to the whole low-arctic tundra, and we compare the simulated green-up dates with the green-up dates obtained from satellite observations and to in situ measurements of deciduous shrub leaf appearance. The model, although calibrated for taiga, performs remarkably well in tundra, with root mean square error ranging between 4 and 8 days for most of the tundra region, the same order as in taiga regions. The results seem to indicate that air temperature is the main factor controlling spring leaf phenology in tundra, just as in taiga, although these results do not permit us to reject soil temperature as the main trigger for leaf appearance in tundra. Because our model performs in tundra as well as in taiga, it can be used across the ecotone, and during a northward migration of the species from the taiga to the low-arctic region. The leaf appearance model and the satellite observations reveal that leaf appearance has tended to occur earlier by approximately 10 days both in Alaska since 1975, and in west Siberian tundra since 1965. [ABSTRACT FROM AUTHOR]

The article reflects on the climate lessons from the first International Polar Year (IPY). The section focuses on a unique glimpse of the Arctic from a period before the present era of climate warming is found in the records of the first IPY of 1882-83. The purpose of the study was to discover the fundamental laws governing global meteorological and geophysics phenomena. The study also aims to contribute significant information to the upcoming fourth IPY scheduled for 2007-08: to understand the climate changes currently unfolding in the Arctic/Antarctic within the context of the past.

The article offers information on a study by Norwegian researchers which suggests that large and increasingly frequent forest fires in boreal regions are the primary cause of atmospheric long-range transport of carbon particles to the Arctic, where they speed up melting of glaciers and sea ice. South and east Asian anthropogenic emissions are found in the study to be less important sources than has been suggested. The study warns, however, that global warming will mean even more boreal forest fires.