Climatic Change, Wildfire, and Conservation

Abstract:  Climatic variability is a dominant factor affecting large wildfires in the western United States, an observation supported by palaeoecological data on charcoal in lake sediments and reconstructions from fire-scarred trees. Although current fire management focuses on fuel reductions to bring fuel loadings back to their historical ranges, at the regional scale extreme fire weather is still the dominant influence on area burned and fire severity. Current forecasting tools are limited to short-term predictions of fire weather, but increased understanding of large-scale oceanic and atmospheric patterns in the Pacific Ocean (e.g., El Niño Southern Oscillation, Pacific Decadal Oscillation) may improve our ability to predict climatic variability at seasonal to annual leads. Associations between these quasi-periodic patterns and fire occurrence, though evident in some regions, have been difficult to establish in others. Increased temperature in the future will likely extend fire seasons throughout the western United States, with more fires occurring earlier and later than is currently typical, and will increase the total area burned in some regions. If climatic change increases the amplitude and duration of extreme fire weather, we can expect significant changes in the distribution and abundance of dominant plant species in some ecosystems, which would thus affect habitat of some sensitive plant and animal species. Some species that are sensitive to fire may decline, whereas the distribution and abundance of species favored by fire may be enhanced. The effects of climatic change will partially depend on the extent to which resource management modifies vegetation structure and fuels.     

Changes of Soil Microbiological Properties Caused by Land Use Changing From Rice–Wheat Rotation to Vegetable Cultivation

A survey was done recently in Jiaxing city of Zhejiang Province in the Yangtze River Delta to compare the differences of soil microbiological properties among paddy soils with different land use including continuous open-field vegetable cultivation (OFVC), plastic-greenhouse vegetable cultivation (PGVC) and traditional rice–wheat rotation (RWR). The soil types included are percolating, permeable and waterlogged paddy soils. The results indicate that the microbial flora was markedly changed as the land use changed for all the three soil types. In continuous vegetable cultivation soils, especially in PGVC soils, the bacteria amounts decreased dramatically, but the fungal and actinomyce amounts increased as compared with RWR soils. The dehydrogenase activities decreased significantly in vegetable soils, especially in PGVC soils as compared with RWR soils. The microbial biomass C and the total phospholipid contents (TPL) in vegetable cultivation soil greatly decreased as compared with RWR soils. Biolog analysis indicated that the kinds of carbon sources that could be metabolized by native microbes in PGVC soils greatly decreased as compared with OFVC soils and RWR soils, revealing that microbial diversity had decreased since land use change. The activities of some soil enzymes including urease, invertase and phosphase were all lower in OFVC soils than those in RWR soils, and those in PGVC soils were the lowest. The degradation of microbiological activities in continuous vegetable cultivation soils, especially in PGVC soils, as compared with RWR soils might have been caused by soil acidification and accumulation of salts due to overuse of both organic and inorganic fertilizers in vegetable cultivation.     

区域土地利用变化对土壤磷含量的影响评价研究

研究土壤磷含量的时空演变规律对改善土地管理水平和提高土壤质量具有重要的指导作用。文章选取江苏省原锡山市作为研究区域,以1982年和2005年土壤全磷和速效磷含量作为研究对象,研究探讨土地利用变化对土壤磷含量的影响,进而表明人类活动对生态系统和环境的影响。通过统计分析表明,20年来原锡山市土壤全磷含量降低0.48g·kg-1,土壤速效磷含量升高26.16mg·kg-1。通过变异函数分析,20年来原锡山市全磷和速效磷的变异函数理论模型都是指数型,但块金方差与基台值的比值、自相关阀值发生了较大变化;Kriging插值分析结果表明,1982年全磷和速效磷的分布比较简单;2005年全磷分布较为简单,土壤速效磷分布较为复杂。Kriging插值分析还表明,20年来原锡山市土壤全磷含量降低,空间变异显著;土壤速效磷含量升高,空间变异显著。     

连云港海平面变化与地震相关性的探讨

为探索海平面变化与地震相关的前兆信息,利用了连云港验潮站长达４３年的验潮资料。结合华北地区４次７级以上强震和江苏及其以东黄海海域１８次中强以上地震的震例分析后认为：经基本消除主要干扰因素的连云港平均海平面变化,表征了与地震有关的地壳形变信息。它对监测华北地区强震和江苏及邻近地区的中强震,具有一定的参考价值。     

The development of first-possession rules in US mining, 1872–1920: theory, evidence, and policy implications

This paper applies a property rights framework to federal mineral lands in the western United States from the enactment of the Mining Law in 1872 until the enactment of the Mineral Leasing Act for fossil fuels in 1920. There are two principal findings. First, the Mining Law appears to have been an effective means for assigning rights to mineral stocks on public lands (at least through 1920). This conclusion is supported by evidence from claim disputes in the West. Second, the impetus for the Mineral Leasing Act did not derive from the different physical characteristics of hardrock minerals and petroleum. The relevance of these conclusions to contemporary mineral policy is also discussed.     

气候变化对莱州湾地区水资源脆弱性的影响

论文首先分析了在现状年(1993年)供水能力和需水条件下,1960～1993年的气候波动对莱州湾地区水资源供需平衡和脆弱性的影响。然后根据未来气候情景分析了在2000规划年和2020规划年供水能力和需水要求下,未来气候变化(2000～2042年)对水资源供需平衡及脆弱性的影响。在农业需水保证率50%时,2000～2019年水资源供需基本平衡,但2020～2042年水资源短缺20～57亿m³。若考虑未来气温的上升,则水资源短缺进一步加大。因此,2020年以后需在调入56亿m³客水资源基础上,从区外调入更多稳定的水量以保证该地区社会经济的可持续发展。     

江苏省耕地面积变化与经济增长的协整性与因果关系分析

江苏省近年来随着社会经济的发展,耕地面积急剧减少,土地利用变化和经济增长二者关系更为明显和完整,具有极好的典型性和代表性。论文利用近20年来耕地面积、经济增长与城市化水平之间的长序列统计资料,对江苏省1981～2004年间的耕地面积与经济增长及城市化水平的协整性和因果关系进行了研究。研究表明:耕地面积、GDP与城市化水平均是不平稳的时间序列,直接对其进行回归分析是不严谨的;江苏省耕地面积变化与经济增长之间不具有长期的协整性;江苏省耕地面积与GDP、城市化水平之间只存在单向的因果关系。通过研究,认为目前的土地利用方式极不合理。因此,降低耕地减少速度,提高土地利用效率是非常紧迫的战略问题。     

CDM Forestry and the Ultimate Objective of the Climate Convention

In its Article 2, the U.N. Framework Convention on Climate Change policymakers gave themselves a long-term dynamic mandate under uncertainty. Taking the example of forestry activities in developing countries, the present article discusses whether land-based climate change mitigation measures in the context of compensation mechanisms for human-induced greenhouse gas emissions are covered under the UNFCCC's ultimate objective. Both the problem of climate change and human intervention act over long, yet finite timeframes. The article argues for taking a dynamic 100-year timeframe as reference for present-day activities. It concludes that increasing biotic carbon storage is legitimate for measures that contribute to biodiversity conservation, as long as it does not serve as a pretext for neglecting technological change. Among all forestry options, the list of priorities should be avoiding deforestation and devegetation, sustainable forest management, and afforestation. The problem of saturation can be encountered by the combination of forestry with the increased use of wood products and bioenergy. Concluding, the article gathers criteria for forest climate activities in the post-2012 regime. JEL Classification: Q23, Q54; Q57; Q58     

Baselines for land-use change in the tropics: application to avoided deforestation projects

Although forest conservation activities, particularly in the tropics, offer significant potential for mitigating carbon (C) emissions, these types of activities have faced obstacles in the policy arena caused by the difficulty in determining key elements of the project cycle, particularly the baseline. A baseline for forest conservation has two main components: the projected land-use change and the corresponding carbon stocks in applicable pools in vegetation and soil, with land-use change being the most difficult to address analytically. In this paper we focus on developing and comparing three models, ranging from relatively simple extrapolations of past trends in land use based on simple drivers such as population growth to more complex extrapolations of past trends using spatially explicit models of land-use change driven by biophysical and socioeconomic factors. The three models used for making baseline projections of tropical deforestation at the regional scale are: the Forest Area Change (FAC) model, the Land Use and Carbon Sequestration (LUCS) model, and the Geographical Modeling (GEOMOD) model. The models were used to project deforestation in six tropical regions that featured different ecological and socioeconomic conditions, population dynamics, and uses of the land: (1) northern Belize; (2) Santa Cruz State, Bolivia; (3) Paraná State, Brazil; (4) Campeche, Mexico; (5) Chiapas, Mexico; and (6) Michoacán, Mexico. A comparison of all model outputs across all six regions shows that each model produced quite different deforestation baselines. In general, the simplest FAC model, applied at the national administrative-unit scale, projected the highest amount of forest loss (four out of six regions) and the LUCS model the least amount of loss (four out of five regions). Based on simulations of GEOMOD, we found that readily observable physical and biological factors as well as distance to areas of past disturbance were each about twice as important as either sociological/demographic or economic/infrastructure factors (less observable) in explaining empirical land-use patterns. We propose from the lessons learned, a methodology comprised of three main steps and six tasks can be used to begin developing credible baselines. We also propose that the baselines be projected over a 10-year period because, although projections beyond 10 years are feasible, they are likely to be unrealistic for policy purposes. In the first step, an historic land-use change and deforestation estimate is made by determining the analytic domain (size of the region relative to the size of proposed project), obtaining historic data, analyzing candidate baseline drivers, and identifying three to four major drivers. In the second step, a baseline of where deforestation is likely to occur–a potential land-use change (PLUC) map—is produced using a spatial model such as GEOMOD that uses the key drivers from step one. Then rates of deforestation are projected over a 10-year baseline period based on one of the three models. Using the PLUC maps, projected rates of deforestation, and carbon stock estimates, baseline projections are developed that can be used for project GHG accounting and crediting purposes: The final step proposes that, at agreed interval (e.g., about 10 years), the baseline assumptions about baseline drivers be re-assessed. This step reviews the viability of the 10-year baseline in light of changes in one or more key baseline drivers (e.g., new roads, new communities, new protected area, etc.). The potential land-use change map and estimates of rates of deforestation could be re-done at the agreed interval, allowing the deforestation rates and changes in spatial drivers to be incorporated into a defense of the existing baseline, or the derivation of a new baseline projection.     

Accounting for time in Mitigating Global Warming through land-use change and forestry

Many proposed activities formitigating global warming in the land-use change and forestry(LUCF) sector differ from measures to avoid fossilfuel emissions because carbon (C) may be held out ofthe atmosphere only temporarily. In addition, thetiming of the effects is usually different. Many LUCFactivities alter C fluxes to and from the atmosphereseveral decades into the future, whereas fossil fuelemissions avoidance has immediate effects. Non-CO₂ greenhouse gases (GHGs), which are animportant part of emissions from deforestation inlow-latitude regions, also pose complications forcomparisons between fossil fuel and LUCF, since themechanism generally used to compare these gases(global warming potentials) assumes simultaneousemissions. A common numeraire is needed to expressglobal warming mitigation benefits of different kindsof projects, such as fossil fuel emissions reduction,C sequestration in forest plantations, avoideddeforestation by creating protected areas and throughpolicy changes to slow rates of land-use changes suchas clearing. Megagram (Mg)-year (also known as`ton-year') accounting provides a mechanism forexpressing the benefits of activities such as these ona consistent basis. One can calculate the atmosphericload of each GHG that will be present in each year,expressed as C in the form of CO₂ and itsinstantaneous impact equivalent contributed by othergases. The atmospheric load of CO₂-equivalent Cpresent over a time horizon is a possible indicator ofthe climatic impact of the emission that placed thisload in the atmosphere. Conversely, this index alsoprovides a measure of the benefit of notproducing the emission. One accounting methodcompares sequestered CO₂ in trees with theCO₂ that would be in the atmosphere had thesequestration project not been undertaken, whileanother method (used in this paper) compares theatmospheric load of C (or equivalent in non-CO₂GHGs) in both project and no-project scenarios.Time preference, expressed by means of a discount rateon C, can be applied to Mg-year equivalencecalculations to allow societal decisions regarding thevalue of time to be integrated into the system forcalculating global warming impacts and benefits. Giving a high value to time, either by raising thediscount rate or by shortening the time horizon,increases the value attributed to temporarysequestration (such as many forest plantationprojects). A high value for time also favorsmitigation measures that have rapid effects (such asslowing deforestation rates) as compared to measuresthat only affect emissions years in the future (suchas creating protected areas in countries with largeareas of remaining forest). Decisions on temporalissues will guide mitigation efforts towards optionsthat may or may not be desirable on the basis ofsocial and environmental effects in spheres other thanglobal warming. How sustainable development criteriaare incorporated into the approval and creditingsystems for activities under the Kyoto Protocol willdetermine the overall environmental and social impactsof pending decisions on temporal issues.