727 research outputs found
EU Peatlands: Current Carbon Stocks and Trace Gas Fluxes
Peatlands in Europe has formed a significant sink for atmospheric CO2 since the last glacial maximum. Currently they are estimated to hold ca. 42 Gt carbon in the form of peat and are therefore a considerable component in the European carbon budget. Due to the generally wet soil conditions in peatlands they are also significant emitters of the strong greenhouse gas (GHG) methane (CH4) and in some cases also of nitrous oxide (N2O). The EU funded CarboEurope-GHG Concerted Action attempts to develop a reliable and complete greenhouse gas budget for Europe and this report aims to provide a review and synthesis of the available information about GHG exchanges in European peatlands and their underlying processes. A best estimate for all the European countries shows that some are currently sinks for atmospheric CO2 while others are sources. In contrast, for CH4 and N2O, only the sources are relevant. Whilst some countries are CO2 sinks, all countries are net GHG emitters from peatlands. The results presented, however, carry large uncertainties, which cannot be adequately quantified yet. One outstanding uncertainty is the distribution of land use types, particular in Russia, the largest European peat nation. The synthesis of GHG exchange, nevertheless, indicates some interesting features. Russia hosts an estimated 41% of European peatlands and contributes most to all GHG exchanges (CO2: 25%, CH4: 52%, N2O: 26%, Total: 37%). Germany is the second-largest emitter (12% of European total) although it contains only 3.2% of European peatlands. The reason is the use of most of the peatland area for intensive cropland and grassland. The largest CO2 emitters are countries with large agricultural peatland areas (Russia, Germany, Belarus, Poland), the largest N2O emitters are those with large agricultural fen areas (Russia, Germany, Finland). In contrast, the largest CH4 emitters are concentrated in regions with large areas of intact mires, namely Russia and Scandinavia. High average emission densities above 3.5 t C-equiv. ha-1 are found in the Southeast Mediterranean, Germany and the Netherlands where agricultural use of peatlands is intense. Low average emission densities below 0.3 t C-equiv. ha-1 occur where mires and peatland forests dominate, e.g. Finland and the UK. This report concludes by pointing at key gaps in our knowledge about peatland carbon stocks and GHG exchanges which include insufficient basic information on areal distribution of peatlands, measurements of peat depth and also a lack of flux datasets providing full annual budgets of GHG exchanges
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Air-Sea Exchange in the Global Mercury Cycle
We present results from a new global atmospheric mercury model coupled with a mixed layer slab ocean. The ocean model describes the interactions of the mixed layer with the atmosphere and deep ocean, as well as conversion between elemental, divalent, and nonreactive mercury species. Our global mean aqueous concentrations of 0.07 pM elemental, 0.80 pM reactive, and 1.51 pM total mercury agree with observations. The ocean provides a 14.1 Mmol yrâ1 source of mercury to the atmosphere, at the upper end of previous estimates. Re-emission of previously deposited mercury constitutes 89% of this flux. Ocean emissions are largest in the tropics and downwind of industrial regions. Midlatitude ocean emissions display a large seasonal cycle induced by biological productivity. Oceans contribute 54% (36%) of surface atmospheric mercury in the Southern (Northern) Hemisphere. We find a large net loss of mercury to the deep ocean (8.7 Mmol yrâ1), implying a âŒ0.7%/year increase in deep ocean concentrations.Earth and Planetary SciencesEngineering and Applied Science
Global Health and Economic Impacts of Future Ozone Pollution
Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).We assess the human health and economic impacts of projected 2000-2050 changes in ozone pollution using the MIT Emissions Prediction and Policy Analysis-Health Effects (EPPA-HE) model, in combination with results from the GEOS-Chem global tropospheric chemistry model that simulated climate and chemistry effects of IPCC SRES emissions. We use EPPA to assess the human health damages (including acute mortality and morbidity outcomes) caused by ozone pollution and quantify their economic impacts in sixteen world regions. We compare the costs of ozone pollution under scenarios with 2000 and 2050 ozone precursor and greenhouse gas emissions (SRES A1B scenario). We estimate that health costs due to global ozone pollution above pre-industrial levels by 2050 will be ) and that acute mortalities will exceed 2 million. We find that previous methodologies underestimate costs of air pollution by more than a third because they do not take into account the long-term, compounding effects of health costs. The economic effects of emissions changes far exceed the influence of climate alone.United States Department of Energy, Office of
Science (BER) grants DE-FG02-94ER61937 and DE-FG02-93ER61677, the United States
Environmental Protection Agency grant EPA-XA-83344601-0, and the industrial and foundation
sponsors of the MIT Joint Program on the Science and Policy of Global Change
Understanding Human and Ecosystem Dynamics in the Kola Arctic : A Participatory Integrated Study
The Lake Imandra watershed is located in one of the most developed regions in the Arctic - the Kola Peninsula of Russia. Approximately 300 000 people live on the roughly 27 000 kmÂČ watershed, making it one of the most densely populated areas of the Arctic. Most of the people are involved in large-scale mineral extraction and processing and the infrastructure needed to support this industry. This paper reports the results of a pilot project staged for the Lake Imandra watershed that has put human dynamics within the framework of ecosystem change to integrate available information and formulate conceptual models of likely future scenarios. The observation period is one of both rapid economic growth and human expansion, with an overall economic decline in the past decade. We are applying the Participatory Integrated Assessment (PIA) approach to integrate information, identify information gaps, generate likely future scenarios, and link scientific findings to the decision-making process. We found an increasingly vulnerable human population in varying states of awareness about their local environment and fully cognizant of their economic troubles, with many determined to attempt maintenance of relatively high population densities in the near future even as many residents of northern Russia migrate south. A series of workshops have involved the citizens and local decision makers in an attempt to tap their knowledge of the region and to increase their awareness about the linkages between the socioeconomic and ecological components.Le bassin hydrographique du lac Imandra est situĂ© dans l'une des rĂ©gions les plus dĂ©veloppĂ©es de l'Arctique, soit la presqu'Ăźle de Kola, en Russie. PrĂšs de 300 000 personnes vivent dans la zone du bassin qui couvre environ 27 000 kmÂČ, ce qui en fait l'une des rĂ©gions les plus peuplĂ©es de l'Arctique. La plupart des habitants travaillent dans l'extraction et le traitement miniers Ă grande Ă©chelle ainsi que dans l'infrastructure qui soutient cette industrie. Le prĂ©sent article rapporte les rĂ©sultats d'un projet pilote mis sur pied pour le bassin du lac Imandra, projet qui a placĂ© la dynamique humaine dans le cadre du changement des Ă©cosystĂšmes, afin d'intĂ©grer l'information disponible et de formuler des modĂšles conceptuels de scĂ©narios probables dans l'avenir. La pĂ©riode d'observation en est une Ă la fois de croissance Ă©conomique et d'expansion dĂ©mographique rapides, suivie d'un dĂ©clin gĂ©nĂ©ral au cours de la derniĂšre dĂ©cennie. On a recours Ă la mĂ©thode d'Ă©valuation participative intĂ©grĂ©e (EPI) pour intĂ©grer l'information, y dĂ©gager des lacunes, gĂ©nĂ©rer des scĂ©narios probables dans l'avenir et Ă©tablir un lien entre rĂ©sultats de la recherche et processus dĂ©cisionnel. On a trouvĂ© qu'il y avait une population humaine de plus en plus vulnĂ©rable qui Ă©tait sensibilisĂ©e Ă divers degrĂ©s aux problĂšmes locaux de l'environnement et pleinement consciente des difficultĂ©s Ă©conomiques, population dont une bonne part Ă©tait fermement dĂ©cidĂ©e Ă tenter de maintenir Ă brĂšve Ă©chĂ©ance des densitĂ©s de population relativement Ă©levĂ©es, alors mĂȘme que les rĂ©sidents du nord de la Russie migrent en grand nombre vers le Sud. On a tenu une sĂ©rie d'ateliers avec citoyens et dĂ©cideurs locaux pour chercher Ă capter leurs connaissances de la rĂ©gion et Ă accroĂźtre leur sensibilisation aux liens existant entre les composantes socio-Ă©conomiques et Ă©cologiques
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Observations of Reactive Gaseous Mercury in the Free Troposphere at the Mount Bachelor Observatory
We measured gaseous elemental mercury (GEM), particulate mercury (PHg), and reactive gaseous mercury (RGM), along with CO, ozone, and aerosol scatter at the Mount Bachelor Observatory (2.7 km above sea level), Oregon, from May to August 2005. The mean mercury concentrations (at standard conditions) were 1.54 ng/m3 (GEM), 5.2 pg/m3 (PHg), and 43 pg/m3 (RGM). RGM enhancements, up to 600 pg/m3, occurred at night and were linked to a diurnal pattern of upslope and downslope flows that mixed in boundary layer air during the day and free tropospheric air at night. During the night, RGM was inversely correlated (P < 0.0001) with CO (r = â0.36), GEM (r = â0.73), and H2O (r = â0.44), was positively correlated with ozone (r = 0.38), and could not be linked to recent anthropogenic emissions from local sources or long-range transport. Principal component analysis and a composite of change in RGM versus change in GEM during RGM enhancements indicate that a nearly quantitative shift in speciation is associated with increases in ozone and decreases in water vapor and CO. This argues that high concentrations of RGM are present in the free troposphere because of in situ oxidation of GEM to RGM. A global chemical transport model reproduces the RGM mean and diurnal pattern but underestimates the magnitude of the largest observed enhancements. Since the only modeled, in situ RGM production mechanisms are oxidation of GEM by ozone and OH, this implies that there are faster reaction rates or additional RGM production mechanisms in the free troposphere.Earth and Planetary SciencesEngineering and Applied Science
Knowledge politics and new converging technologies: a social epistemological perspective
The ânew converging technologiesâ refers to the prospect of advancing the human condition by the integrated study and application of nanotechnology, biotechnology, information technology and the cognitive sciences - or âNBICâ. In recent years, it has loomed large, albeit with somewhat different emphases, in national science policy agendas throughout the world. This article considers the political and intellectual sources - both historical and contemporary - of the converging technologies agenda. Underlying it is a fluid conception of humanity that is captured by the ethically challenging notion of âenhancing evolutionâ
Subnational climate entrepreneurship: innovative climate action in California and SĂŁo Paulo
The distinct role of subnational governments such as states and provinces in addressing climate change has been increasingly acknowledged. But while most studies investigate the causes and consequences of particular governmentsâ actions and networking activities, this article argues that subnational governments can develop climate action as a collective entrepreneurial activity. Addressing many elements explored in this special issue, it focuses on the second question and identifies climate entrepreneurship in two subnational governmentsâthe states of California (USA) and SĂŁo Paulo (Brazil). Examining internal action, as well as interaction with local authorities, national governments and the international regime, entrepreneurial activities are identified in the invention, diffusion and evaluation of subnational climate policy in each case. The article draws from the recent scholarship on policy innovation, entrepreneurship and climate governance. It contributes to the literature by exploring entrepreneurial subnational government activity in addressing climate change and expanding the understanding of the effects of policy innovation at the subnational level
Understanding mercury oxidation and airâsnow exchange on the East Antarctic Plateau: a modeling study
Distinct diurnal and seasonal variations of mercury (Hg) have been observed
in near-surface air at Concordia Station on the East Antarctic Plateau, but
the processes controlling these characteristics are not well understood.
Here, we use a box model to interpret the Hg0 (gaseous elemental
mercury) measurements in thes year 2013. The model includes atmospheric Hg0
oxidation (by OH, O3, or bromine), surface snow HgII (oxidized
mercury) reduction, and airâsnow exchange, and is driven by meteorological
fields from a regional climate model. The simulations suggest that a
photochemically driven mercury diurnal cycle occurs at the airâsnow interface
in austral summer. The fast oxidation of Hg0 in summer may be provided
by a two-step bromine-initiated scheme, which is favored by low temperature
and high nitrogen oxides at Concordia. The summertime diurnal variations of
Hg0 (peaking during daytime) may be confined within several tens of
meters above the snow surface and affected by changing mixed layer depths.
Snow re-emission of Hg0 is mainly driven by photoreduction of snow
HgII in summer. Intermittent warming events and a hypothesized reduction
of HgII occurring in snow in the dark may be important processes
controlling the mercury variations in the non-summer period, although their
relative importance is uncertain. The Br-initiated oxidation of Hg0 is
expected to be slower at Summit Station in Greenland than at Concordia (due to their
difference in temperature and levels of nitrogen oxides and ozone), which may
contribute to the observed differences in the summertime diurnal variations
of Hg0 between these two polar inland stations.</p
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