The economic benefits of the adoption of conservation tillage depend on site-specific factors including soil characteristics,
local climatic conditions, cropping patterns, and other attributes of the overall farming operation. While it is possible
to draw some general inferences about components of economic returns and costs, a comprehensive assessment of the net private
benefits from greater use of conservation tillage is not feasible.
Received: 4 December 1997 · Accepted: 30 March 1998 相似文献
ABSTRACT. This article examines the dramatic changes brought to English townscapes by Islam, Hinduism, and Sikhism. These “new” religions have arrived with the large‐scale immigration and subsequent natural growth of the minority ethnic populations of Great Britain since the 1950s. The article traces the growth and distribution of these populations and religions, as well as the development of their places of worship from front‐room prayer rooms to cathedral‐scale buildings. It explores the way in which the British planning process, dedicated to preserving the traditional, has engaged with the exotic. 相似文献
Abstract It is argued here that stringent, early emission reductions are necessary in order to minimize ‘dangerous anthropogenic interference in the climate system’ (DAI), the stated Objective of Article 2 of the UNFCCC (United Nations Framework Convention on Climate Change). Given probability distribution functions (pdfs) for climate sensitivity and the temperature threshold for harm consistent with currently available evidence, and accepting a 10% risk of unacceptable damage as the threshold for ‘danger’, it is not possible to avoid DAI. Having adopted a precautionary approach in setting emission trajectories, the possibility arises that future resolution of uncertainties concerning climate sensitivity and the harm threshold may show the climate sensitivity to be low (1–2 K) and the harm threshold high (2 K rather than 1 K). Using a simple coupled climate-carbon cycle model, it is shown that if the climate sensitivity were to be definitively determined to be 2 K in 2020, then the emission reductions achieved by that time and planned for the next two decades are still fully needed. Only if climate sensitivity is very low (1 K) and the harm threshold is high (2 K) would the emissions achieved by 2020 not have been fully necessary. However, this would still lead to changes in ocean chemistry that are likely to be highly detrimental to marine life. Thus, when the full spectrum of impacts is considered, there is no plausible set of assumptions under which stringent near-term emission reductions are rendered unnecessary. 相似文献
We carry out a structured review of the peer-reviewed literature to assess the factors that constrain and enable the uptake of long-term climate information in a wide range of sectoral investment and planning decisions. Common applications of long-term climate information are shown to relate to urban planning and infrastructure, as well as flood and coastal management. Analysis of the identified literature highlights five categories of constraints: disconnection between users and producers of climate information, limitations of climate information, financial and technical constraints, political economy and institutional constraints and finally psycho-social constraints. Five categories of enablers to the uptake of long-term climate information in decision-making are also identified: collaboration and bridge work, increased accessibility of climate information, improvement in the underlying science, institutional reform and windows of opportunity for building trust.Policy relevanceOur review suggests that stand-alone interventions aimed at promoting the uptake of climate information into decision-making are unlikely to succeed without genuine and sustained relationships between producers and users. We also highlight that not every decision requires consideration of long-term climate information for successful outcomes to be achieved. This is particularly the case in the context of developing countries, where the immediacy of development challenges means that decision makers often prioritize short-term interventions. Care should therefore be taken to ensure that information is targeted towards investments and planning decisions that are relevant to longer-term timescales. 相似文献
Involving a wide-range of stakeholders at different moments in the planning of urban adaptation to climate change can help to overcome different barriers to adaptation, such as a lack of common perception, or control over options. This Article argues for an approach that involves a wide range of actors throughout the planning process in order to confront the challenges of urban adaptation to climate change. It builds on the results of a three-year participatory action research project to identify the catalysts with which local administrations can overcome the lack of data, the low level of engagement around the climate issue, and the cause-and-effect linkages of climate change impacts on the urban environment. Significant factors include territorial rootedness, leveraging actors’ experience, interaction between actors, as well as the valuing of local actors as experts of territorial management rather than as novices with regard to climate change adaptation. In addition to contributing towards the engagement of a large number of stakeholders around adaptation issues, a planning process that involves representatives from various sectors and during several stages contributes to a greater understanding of these issues and their linkages. It follows that such a process will bring changes to urban practices by better articulating local concerns about climatic issues.Policy relevanceAlthough participation is commonly advocated in policy responses to climate change, only few empirical studies have investigated the ways in which local actors' knowledge can be integrated into climate change adaptation planning processes. The article builds on the results of an action research project carried out in Québec City, Canada, to address the relevance of involving a progressively broader range of actors as the adaptation process moves through its various phases. Given that a multitude of barriers to adaptation are at play at different times in a municipality, collaborations between local stakeholders emerge as a key factor. These collaborations provide greater insight into the linkages between climate change impacts and the urban environment and, in doing so, bring into question ordinary urban management and design practices. 相似文献
ABSTRACTForest and agricultural sector response to comprehensive climate policy is well represented in the literature. Less analysis has been devoted to piecemeal solutions. We use the Forest and Agriculture Sector Optimization Model with Greenhouse Gases (FASOMGHG) to project the individual and combined effect of three existing U.S. Department of Agriculture programmes with potential to increase greenhouse gas (GHG) mitigation. We find that a combined policy scenario may achieve greater mitigation than individual constituent programmes, suggesting the possibility of complementary spillover effects in some periods. Mitigation varies over time, however, and some periods experience net emissions as markets and management practices respond to initial policy shocks. The regional distribution of GHG mitigation also varies between policy scenario. Differences in the magnitude and imputed cost of mitigation under each scenario, generating negative values for some programmes and time periods, reinforces the need to evaluate portfolio design to cost-effectively achieve near-term GHG mitigation.Key policy insights
Increased near-term GHG mitigation in the forest and agriculture sectors in the US may be possible by expanding or refocusing the emphasis of existing programmes.
Implementing several such forest and agricultural programmes simultaneously may lead to greater GHG mitigation than when implemented separately, indicating the possibility of positive spillover effects.
Programmes targeted to agricultural management may hold outsized potential to achieve near-term GHG mitigation; Policies aimed at influencing land use conversion appear to be more vulnerable to reversion and subject to larger inter-annual swings.
The staged implementation of programmes could also be useful, helping to encourage increased mitigation (or the retention of already achieved mitigation) over time as markets re-equilibrate to initial shocks.
Though the particular scenarios assessed here are unique to the US, our findings may be applicable to other locations outside the US where land management is influenced by individual market actors and there is competition between forest and agricultural land uses.
A novel approach is described for limiting transport emissions through a cap-and-trade emissions trading scheme, whereby local governments would be the participants of emissions trading. It is proposed that emissions trading for passenger road transport has the effect of channelling the carbon costs away from fuel prices to land use costs. A ‘municipal emissions trading scheme’ could achieve this—local governments would have to cover vehicle traffic emissions generated by homes, businesses and industry on their territory. Municipalities are able to participate in an emissions trading scheme because they have planning control over development on their territory, and could control the amount of future vehicular traffic. Through planning, municipalities have access to a wide range of strategies to minimize transport emissions. Municipal emissions can be calculated as a share of total national road transport emissions with the help of a gravity model of traffic attraction. A municipal emissions trading system would result in capping and controlling passenger road transport emissions, not through raising fuel prices or importing credits, but by enforcing prudent and climate-efficient urban planning practices. 相似文献