Susan Subak

Pressures, trends, and impacts in coastal zones: Interactions between socioeconomic and natural systems

This paper assesses the status of coastal zones in the context of expected climate change and its related impacts, as well as current and future socioeconomic pressures and impacts. It is argued that external stresses and shocks relating to sea-level rise and other changes will tend to exacerbate existing environmental pressures and damage in coastal zones. Coastal zones are under increasing stress because of an interrelated set of planning failures including information, economic market, and policy intervention failures. Moves towards integrated coastal zone management are urgently required to guide the coevolution of natural and human systems. Overtly technocentric claims that assessments of vulnerability undertaken to date are overestimates of likely future damages from global warming are premature. While it is the case that forecasts of sea-level rise have been scaled down, much uncertainty remains over, for example, combined storm, sea surge, and other events. In any case, within the socioeconomic analyses of the problem, resource valuations have been at best only partial and have failed to incorporate sensitivity analysis in terms of the discount rates utilized. This would indicate an underestimation of potential damage costs. Overall, a precautionary approach is justified based on the need to act ahead of adequate information acquisition, economically efficient resource pricing and proactive coastal planning.

Global environmental costs of beef production

This paper evaluates the impact on greenhouse gas emissions of beef produced under different management systems and compares these results with the estimated biophysical capital alteration of these same systems. The environmental impacts of a specific intensive US feedlot system and a traditional African pastoral system are calculated using a methodology that includes the major land-use and energy-related emissions. Although assessments of carbon dioxide emissions find much greater impacts related to the US feedlot mode, the methane intensity of the pastoral mode is much larger because of the lower productivity of these systems. It is found that when indirect sources, which include emissions from fossil fuels and foregone carbon storage on appropriated land, are considered as well as emissions from enteric fermentation and wastes, the social costs of the feedlot system at 15 kg CO2 equivalent:kg beef are more than double that of the pastoralist system. Accordingly, the results of the more complete greenhouse gas emissions analysis were found to converge somewhat with the biophysical capital alteration approach in this example, although it is also argued that the entropy-based environmental indicators may have limited use in evaluating agro-ecosystems’ contribution to climate change. Given an assumed, albeit uncertain, climate change impact value, a tax on beef production of about 9% of the unit price would represent the upper limit of the shadow costs of the associated greenhouse gas emissions flux from feedlot systems as estimated here, and a central value would correspond to a tax of about 4%.

Methane embodied in the international trade of commodities: Implications for global emissions☆

Abstract Countries are now setting goals seeking to limit emissions of carbon dioxide (CO 2 ), and many countries are also addressing measures to control methane (CH 4 ), the next most important gas after CO 2 . Current methods for estimating domestic greenhouse gas emissions do not take into account CH 4 and other gases released abroad when producing the imported goods. In this paper, the amount of CH 4 that is currently released in countries that have not adopted greenhouse gas emissions targets to produce exports consumed in countries that have pledged to stabilize or reduce CH 4 emissions, is analysed. Commodity trading in 1990 that involved the most CH 4 intensive agricultural goods — rice, meat, and milk products — is assessed for six developed countries, the USA, UK, Germany, Japan, France and Canada. The amount of CH 4 ‘embodied’, or released in exporting countries while producing the goods traded with these six countries, is calculated. The total amount of CH 4 embodied in imports from developing countries for these six nations in 1990 is estimated to be nearly 1200 kt, about 7% of emissions from livestock for these importing countries, and 9% of emissions from rice produced within the importing countries own borders. This level is greater than domestic anthropogenic CH 4 released from all sources for most countries (103 out of 140 countries surveyed). The UK is the greatest importer of CH 4 embodied goods, with imports of agricultural products equivalent to 23% of emissions from these agricultural sources. While currently the CH 4 released in producing imports to these countries is small, the rate could grow considerably in the future. Factors that will influence this growth include removal of traditional subsidies and levies in Europe, Japan, the USA and in some developing countries. As developing country livestock production becomes more competitive, the opportunity for trade in CH 4 embodied products is likely to increase. Possible circumvention of national CH 4 targets could be controlled by changing the methodology for estimating national greenhouse gas emissions so that trade is taken into account. The more practical and equitable approach is to extend greenhouse gas emissions targets to all countries participating in the climate convention, using an emission trading scheme or an international funding mechanism for transferring resources.

Estimating above-ground Carbon Fluxes from UK Agricultural Land

Land use changes can result in emissions and removals from the atmosphere of the most important greenhouse gas, carbon dioxide (CO2), thus influencing potential climatic change. In this study, annual agricultural census data is used to estimate the net flux from land use change on UK agricultural land, which comprises over three quarters of the UK land area. The assessment includes a new estimate of changes in carbon storage on arable land due to improvements in yield and changes in area devoted to different crops. The study complements recent assessments of CO2 flux in the forestry sector, and provides an alternative to a previous assessment of CO2 flux in the agricultural sector based on periodic land cover surveys. In this study the authors estimate changes in CO2 emissions and storage from above-ground biomass on agricultural land for the period 1970-1992. Annual CO2-C flux on agricultural land is estimated as 200 to 417 kC per year in the period 1970-1988 and 339 to 371 kC per year during 1988-1992. These results are consistent with the estimated range for 1990 published in the UK national communication to the Framework Convention on Climate Change, but may provide a preferable point estimate for the agricultural sector. The intervals used in this study were selected in order to identify flux changes resulting from important new UK land use policy: the introduction in 1988 of incentives to take arable land out of production, known as set-aside. To date, the set-aside programme has resulted in very little carbon sequestration. However such a policy could result in much greater carbon sequestration in future, as the rotation requirement for such land use has been waived from 1996 onwards.

Forest certification eligibility as a screen for CDM sinks projects

Parties negotiating the Kyoto Protocol recently agreed that Clean Development Mechanism (CDM) investments can include carbon sequestration projects in developing countries. However, guidelines for achieving the socio-economic and environmental objectives of the CDM, and other concerns with sinks projects, have yet to be elaborated. Independently of the Kyoto process, international efforts have advanced to define and certify sustainably managed forests through processes, such as that of the Forest Stewardship Council (FSC). In this paper, the FSC-US principles and criteria for sustainable forest management are evaluated in light of current concerns for guiding afforestation and reforestation projects in the CDM. It is found that the FSC criteria would help to meet some of the objectives of the Kyoto Protocol, including provisions to reduce the risk of premature carbon loss, and features that could somewhat lessen leakage of emissions outside the project area. Existing FSC monitoring and verification procedures provide some, but insufficient, overlap with expected requirements for measuring carbon stock changes. FSC principles and criteria articulate stringent guidelines for meeting environmental and social goals that reflect years of negotiations between environmental, timber, human rights and labor interests.

The contribution of the paper cycle to global warming

Worldwide, paper production is a major industry that contributes about 3 percent of Gross World Product. The paper cycle involves a broad range of natural resource and environmental impacts because fiber supply relies on trees, paper manufacturing requires fuel inputs, and paper waste disposal can contribute to emissions of the potent greenhouse gas (GHG), methane (CH4). In some countries, the paper cycle may be seen as a net sink for GHG because of reliance on renewable wood by-products and the maintenance of forest plantations. On a worldwide basis, however, this study demonstrates that the paper cycle is a significant contributor to GHG emissions, adding emissions at least comparable in magnitude to that of Australia each year. The estimated global warming contribution of paper in landfills is estimated to be similar to that of paper manufacturing processes, on a heating-equivalent basis. In some temperate regions, original old-growth forests are still harvested to supply pulpwood, resulting in a significant loss of carbon (C) storage. In theory, the paper cycle holds the promise of achieving zero net emissions if pulpwood production, consumption and disposal are carefully managed. In practice, even stabilization of emissions at current levels would be challenging and entail changes comparable to a 20 percent reduction in CH4 generation from landfilled paper, and a 2.5 percent annual increase in plantation establishment would be needed to offset the projected increase in emissions from paper manufacturing.

On evaluating accuracy of national methane inventories

Abstract In the last few years, nearly all industrialized countries have submitted estimates of national inventories of methane and other greenhouse gases as required under the Framework Convention on Climate Change. National inventories of methane emissions in industrialized countries are fairly complete but give some suggestion of underestimation when inventory totals are compared with recent atmospheric measurements and global budgets. In this paper, possible discrepancies are assessed for fossil fuel sources and landfills based on comparisons between independent estimates and national communications. The Kyoto Protocol to the Framework Convention and the European Union make new provisions to develop procedures for technical review of national inventories and projections, and requirements for more thorough documentation from parties, which should improve accuracy. Limits to accuracy and the political implications of underestimation are discussed in this article, along with suggestions for improving inventories through better analysis, documentation and review procedures.

Analysis of weather effects on variability in Lyme disease incidence in the northeastern United States.

In this study, variability in reported Lyme disease incidence between 1993 and 2001 was analyzed in seven states in the northeastern part of the USA. Positive significant correlations at p < 0.05 were found in all states between early summer disease incidence and the June moisture index in the region two years prior. These correlations may reflect an enhanced nymphal Ixodes scapularis survival under wetter conditions. In some states, significant correlations were observed related to warmer winter weather a year and a half prior to disease incidence, which may have been due to higher survival and activity levels of the white-footed mouse, an important host for I. scapularis ticks.