Uncertainty communication in environmental assessments: views from the Dutch science-policy interface

Scientific assessments of environmental problems, and policy responses to those problems, involve uncertainties of many sorts. Meanwhile, potential impacts of wrong decisions can be far-reaching. This article explores views on uncertainty and uncertainty communication in the Dutch science-policy interface and studies several issues concerning presentation of uncertainty information. Respondents considered uncertainty communication to be important, but it should be concise and policy relevant. Several factors influence policy relevance, including the place of an issue in the policy cycle, and its novelty, topicality and controversiality. Respondents held particular interest in explicit communication on the implications of uncertainty. Related to this, they appreciated information on different sources and types of uncertainty and qualitative aspects of uncertainty (e.g. pedigree charts). The article also studies probability terms, particularly for IPCC's 33–66% probability interval (‘about as likely as not’). Several terms worked reasonably well, with a median interpretation of 40–60%. Finally, as various target groups have different information needs and different amounts of attention for various parts of a report or communication process, it is important to progressively disclose uncertainty information throughout the communication. Improved communication of uncertainty information leads to a deeper understanding and increased awareness of the phenomenon of uncertainty and its policy implications.     

A data support infrastructure for Clean Development Mechanism forestry implementation: an inventory perspective from Cameroon

Clean Development Mechanism (CDM) forestry project development requires highly multi-disciplinary and multiple-source information that can be complex, cumbersome and costly to acquire. Yet developing countries in which CDM projects are created and implemented are often data poor environments and unable to meet such complex information requirements. Using Cameroon as an example, the present paper explores the structure of an enabling host country data support infrastructure for CDM forestry implementation, and also assesses the supply potential of current forestry information. Results include a conceptual data model of CDM project data needs; the list of meso- and macro-level data and information requirements (Demand analysis); and an inventory of relevant data available in Cameroon (Supply analysis). From a comparison of demand and supply, we confirm that data availability and the relevant infrastructure for data or information generation is inadequate for supporting carbon forestry at the micro, meso and macro-levels in Cameroon. The results suggest that current CDM afforestation and reforestation information demands are almost impenetrable for local communities in host countries and pose a number of cross-scale barriers to project adoption. More importantly, we identify proactive regulatory, institutional and capacity building policy strategies for forest data management improvements that could enhance biosphere carbon management uptake in poor countries. CDM forestry information research needs are also highlighted.     

Twin–twin transfusion syndrome: mathematical modelling

Twin–twin transfusion syndrome (TTTS) represents a pregnancy complication with a high risk for perinatal mortality and postnatal morbidity. Mathematical models have been utilized to examine the mechanisms of disease and potential treatment modalities. We developed four consecutive models based on pathophysiology mechanisms. Conceptually, these models remained simple, but with increased complexity in details. We present our models tutorially with the necessary equations expressed in words. The aetiology of TTTS was related to AV anastomoses from donor to recipient and their growth commensurate with placental growth. We assessed that natural growth of placenta and foetuses causes the diameter and length of the AV, as well as the AV's pressure gradient, to increase proportional to gestational age. The AV transfusion then increases faster than natural foetal growth. A progressively increasing discordance subsequently develops, not compensated for by foetal growth. A simulation is performed to show how this discordance in blood volumetric development causes successive discordances in other functions, particularly renal, circulatory, and cardio-vascular, resulting in disease progression to the various stages of TTTS. In conclusion, mathematical modelling of TTTS has provided an understanding of the sequence of events that leads to the various presentations of TTTS stages as well as the efficacy of therapies. Copyright © 2008 John Wiley & Sons, Ltd.     

On the relationships among work characteristics and learning-related behavior: Does age matter?

This 3-wave longitudinal study examined (a) the causal direction of the relationships among psychosocial work characteristics (e.g., job demands, job control, and supervisor support) and indicators of learning-related behavior (e.g., motivation to learn and active problem solving), and (b) whether these relationships differed across age, by comparing the results for young (≤30), middle-aged (31–44) and older (≥45) workers. The results for the total sample revealed significant reciprocal causal relationships among job demands, job control, and learning-related behavior. Furthermore, significant age differences were found in the level of the work characteristics and learning-related behavior, as well as in the cross-lagged relationships among the variables. Compared to earlier—predominantly cross-sectional—results, the present study underlines the importance of taking a dynamic as well as a life-span view on the relationships between work and learning-related behavior. Copyright © 2009 John Wiley & Sons, Ltd.     

The effect of atmospheric mercury depletion events on the net deposition flux around Hudson Bay,Canada

Atmospheric Mercury Depletion Events (AMDE) occur in Arctic and Antarctic regions during polar sunrise. During AMDE, reactive gaseous Hg is rapidly formed through in-situ oxidation of gaseous Hg⁰ by halogens, notably atomic Br and radical BrO. This leads to high Hg deposition fluxes yet an unknown fraction of deposited Hg is reemitted to the atmosphere through subsequent photo-reduction, so that the net deposition flux related to AMDE is not well constrained. Here, Hg and halogens were measured in lichens hanging in tree branches around Hudson Bay where AMDE were reported. Hg concentrations are strongly correlated to halogen elements Br, Cl and I (r² of 0.91, 0.76, 0.81) and decrease with distance from Hudson Bay. We interpret this trend as the result of AMDE, supported by a 1D numerical Br and BrO oxidation model for Hg⁰. Organic carbon normalized Hg contents of down-core lake sediments reported in the literature also show a decreasing trend away from Hudson Bay. Combined observations suggest that at least 50% of Hg deposited during AMDE is reemitted to the atmosphere. Finally, the latitudinal Hg gradient observed in lake sediments suggests that AMDE were active in the Hudson Bay area during the last 90 to 200 years.     

The Southeastern Aerosol Research and Characterization Study, part 3: continuous measurements of fine particulate matter mass and composition

Deployment of continuous analyzers in the Southeastern Aerosol Research and Characterization Study (SEARCH) network began in 1998 and continues today as new technologies are developed. Measurement of fine particulate matter (PM2.5) mass is performed using a dried, 30 degrees C tapered element oscillating microbalance (TEOM). TEOM measurements are complemented by observations of light scattering by nephelometry. Measurements of major constituents include: (1) SO4(2-) via reduction to SO2; (2) NH4+ and NO3- via respective catalytic oxidation and reduction to NO, (3) black carbon (BC) by optical absorption, (4) total carbon by combustion to CO2, and (5) organic carbon by difference between the latter two measurements. Several illustrative examples of continuous data from the SEARCH network are presented. A distinctive composite annual average diurnal pattern is observed for PM2.5 mass, nitrate, and BC, likely indicating the influence of traffic-related emissions, growth, and break up of the boundary layer and formation of ammonium nitrate. Examination of PM2.5 components indicates the need to better understand the continuous composition of the unmeasured "other" category, because it contributes a significant fraction to total mass during periods of high PM2.5 loading. Selected episodes are presented to illustrate applications of SEARCH data. An SO2 conversion rate of 0.2%/hr is derived from an observation of a plume from a coal-fired power plant during early spring, and the importance of local, rural sources of NH3 to the formation of ammonium nitrate in particulate matter (PM) is demonstrated.     

Steam demand reduction of water–gas shift reaction in IGCC power plants with pre-combustion CO2 capture

This paper presents the results of system assessments that were conducted to compare conventional and advanced water–gas shift reactor sections. The latter are specifically tailored for Integrated Gasification Combined Cycles (IGCC) power plants with pre-combustion CO₂ capture. The advanced shift reactor section comprises four staged reactors with distributed feeds of synthesis gas and quench water in between the reactors. Conventional shift reactor sections consist of two sequential reactors with intermediate cooling, where the entire synthesis gas stream passes both reactors.The advanced shift reactor section reduces the steam requirement of the water–gas shift reaction up to 70% in comparison with conventional configurations, at carbon dioxide capture ratios of approximately 85%. This reduction allows for lower electric efficiency penalties, thus higher net electric outputs for IGCC power plants with CO₂ capture. For each case, the CO₂ capture ratio was optimised for the lowest specific lost work per amount of captured CO₂. Both the number of reactors and the total catalyst volume are higher for the advanced shift reactor sections, resulting in increased capital expenses. In case of four staged reactors, the additional expenses are expected to be outperformed by the increased revenues associated with the higher net electric output.