Expert judgement on the underpinning of the assessment threshold used in project-specific calculations of nitrogen depositions

When using a model for a specific (policy) goal, it must first be determined what the scientific application range of a model is. The application range indicates where the model can be used to make reliable statements (given the purpose for which the calculation results are used). If the results are too uncertain (there is a ‘false certainty’), then the model is insufficiently reliable (not valid) for use. There is always a limit to a model. In the context of deposition modelling of individual sources, the scientifically accepted limit below which results are insufficiently reliable lies between approximately 1 and 35 mol/ha/year. Calculation results lower than 1–35 mol/ha/year are scientifically insufficiently reliable for use in decision-making (the model system is then not fit for purpose). Theoretical and empirical considerations, the agreement with other models and peer consensus do not allow room for policy – due to false certainty – to scientifically calculate nitrogen depositions from individual sources and to attribute effects where the deposition is lower than 1–35 mol/ha/year. The current assessment threshold in the Netherlands of 0.005 mol/ha/year cannot therefore be maintained from a scientific, legal and policy perspective; the new assessment threshold to be chosen should be at least 200 times higher. Which assessment threshold between 1 and 35 mol/ha/year is ultimately chosen is not up to science, because no clear answer can be given, and non-scientific factors such as the precautionary principle also play a role. How this precautionary principle is implemented is not a question that can be answered by science. However, the room for policy here is constrained by the scientifically substantiated range of 1–35 mol/ha/year. In Germany, an assessment threshold of 21 mol/ha/year (more than 4,000 times higher than the current assessment threshold in the Netherlands) was chosen based on the precautionary principle. The Netherlands could follow this approach, but from a scientific point of view, higher or lower assessment thresholds are also possible (provided they are chosen within the substantiated range)

Disciplines

The knowledge that is used in IPCC assessments predominantly stems from a wide variety of academic disciplines. Given the high scientific and political profile of the IPCC, the production of knowledge in disciplines is impacted by the existence and dynamics of the IPCC assessment process. In some cases, the dynamics between academic disciplines and the IPCC is characterised by the presence of positive feedback loops, where the production of knowledge is structured and programmed by the IPCC. The subsequent findings then receive a preeminent role in later IPCC assessments, and so the cycle continues. It is important to critically reflect on these dynamics, in order to determine whether visions of climate change’s past, present, and future – for example, pathways for the climate-change problem and its potential solutions, as far as they exist – have not been unduly constrained by the IPCC process. The IPCC runs the risk of unreflexively foregrounding some scientific and policy approaches at the expense of other approaches

Uncertainty management in the IPCC: agreeing to disagree

Looking back over three and a half Assessment Reports, we see that the Intergovernmental Panel on Climate Change (IPCC) has given increasing attention to the management and reporting of uncertainties, but coordination across working groups (WGs) has remained an issue. We argue that there are good reasons for working groups to use different methods to assess uncertainty, thus it is better that working groups agree to disagree rather than seek to bring everybody on one party line.IPCC; uncertainty

Effects of photoperiod and growth substances on tuberization of potato (Solanum tuberosum L.)

May 1978.Covers not scanned.Includes bibliographical references.Four growth chamber and greenhouse experiments were conducted to determine the effects of photoperiod on tuberization of rooted stem cuttings of Solanum tuberosum L. cv. Russet Burbank, Norchip, and Red McClure. The results showed that tuberization can be controlled by growing the plants under the appropriate photoperiod. Rooted stem cuttings grown under long photoperiods (16 and 18 hours) produce few or no tubers. Short photoperiods (8 and 12 hours) increased the rate of tuberization in all experiments. Maximum tuberization occurred at the 12 hour photoperiod. Long photoperiods also stimulated vegetative top growth, particularly stem elongation while under the short photoperiod stems were relatively short. The fresh weight of tubers per plant decreased as the length of the photoperiod increased. A marked tendency for plants to branch was observed with plants under long photoperiod. Under the 8 hour photoperiod, plants developed a single stem, but as the length of the photoperiod increased, the plants showed a greater tendency to branch. Maximum branching occurred under a 16 hour photoperiod. Rooted Norchip stem cuttings did not appear to respond to the treatment photoperiods when compared to the Russet Burbank and Red McClure cuttings. Norchip is apparently a day neutral potato cultivar. Exposure of Russet Burbank and Red McClure "Mother plants" to inducive (10 hr) and non-inducive (16 hr) photoperiods had a marked effect on the tuberizing ability of apical stem cuttings taken from these plants. Apical stem cuttings from the 10 hour photoperiod treatment tuberized earlier and produced heavier tubers whereas cuttings from the 16 hour photoperiod produced few or no tubers in all experiments. Rooted stem cuttings of Solanum tuberosum L. cv' s. Russet Burbank, Norchip, Red McClure and Centennial Russet were treated with 2,4-dichloranisole (DCA), 2,3,5-tri-fodooenzoic acid (TIBA), Indol-3-Acetic acid (IAA), Naphthalene acetic acid (NAA) and Ethrel (E) at various concentration. No significant trends were observed with any of the growth substances with respect to their potential for increasing the number and fresh weight of tubers per plant

Global Precipitation Measurement (GPM) Ground Validation (GV) Science Implementation Plan

For pre-launch algorithm development and post-launch product evaluation Global Precipitation Measurement (GPM) Ground Validation (GV) goes beyond direct comparisons of surface rain rates between ground and satellite measurements to provide the means for improving retrieval algorithms and model applications.Three approaches to GPM GV include direct statistical validation (at the surface), precipitation physics validation (in a vertical columns), and integrated science validation (4-dimensional). These three approaches support five themes: core satellite error characterization; constellation satellites validation; development of physical models of snow, cloud water, and mixed phase; development of cloud-resolving model (CRM) and land-surface models to bridge observations and algorithms; and, development of coupled CRM-land surface modeling for basin-scale water budget studies and natural hazard prediction. This presentation describes the implementation of these approaches

Impending doom or unnecessary panic? The struggle for discursive hegemony in South Africa's acid mine drainage policy problem

This article contributes to the literature on environmental policy controversies. We utilize an Argumentative Discourse Analysis (ADA)-based approachto analyze the struggle for discursive hegemony that took place between competing story-lines in the context of the acid mine drainage (AMD) environmental policy problem, located in the gold mining areas of greater Johannesburg, South Africa. With this article we make a theoretical contribution by presenting and applying an adapted ADA framework strongly focused on the operationalization of key ADA concepts. Our empirical contribution lies in providing a rich and deep analysis of an environmental policy controversy that has not yet been studied from an ADA perspective. In particular, we demonstrate and discuss the complex path to discourse institutionalization followed by the dominant emergent AMD story-line. In conclusion , we recommend steps for updating the ADA approach and developing an accompanying set of guidelines to further enable the operationalization of its concepts