Root distribution plays an important role in both vegetation establishment and restoration of degraded land through influencing soil property and vegetation growth. Root distribution at 0~60 cm depth of A. halodendron was investigated in Horqin Sandy Land. Soil organic carbon (SOC) and nitrogen (SN) concentration as well as carbon and nitrogen in root biomass and necromass were measured. Root length density (RLD) was estimated. Total root biomass, necromass and the RLD at 0~60 cm depth was 172 g/m2, 245 g/m2, and 368 m/m2, respectively. Both biomass and necromass of A. halodendron roots decreased with soil depth, live roots were mainly at 0~20 cm (76% of biomass and 63% of root length), while 73% of the necromass was within 0~30 cm depth. N concentration of roots (biomass and necromass) was about 1.0% and 1.5%, respectively. There were significant differences in SOC concentration between soil layers, but insignificant for SN. Soil C/N ratio decreased with depth (P<0.05). C and N storage for belowground system at 0~60 cm decreased markedly with depth; 41.4% of C and 31.7% of N were allocated to the 0~10 cm layer. Root bio- and necromass together contained similar amount of C to that of the soil itself in the top layer. N stock was dominated by soil nitrogen at all depths, but more so in deeper layers. It is clear that differentiating between soil layers will aid in interpreting A. halodendron efficiency in soil restoration in sandy land. 相似文献
This article provides an ex post analysis of the compliance of the Parties to the Kyoto Protocol during the first commitment period (2008–2012) based on the final data for national GHG emissions and exchanges in carbon units that became available at the end of 2015. On the domestic level, among the 36 countries that fully participated in the Kyoto Protocol, only nine countries emitted higher levels of GHGs than committed and therefore had to resort to flexibility mechanisms. On the international level – i.e. after the use of flexibility mechanisms – all Annex B Parties are in compliance. Countries implemented different compliance strategies: purchasing carbon units abroad, stimulating the domestic use of carbon credits by the private sector and incentivizing domestic emission reductions through climate policies.
Overall, the countries party to the Protocol surpassed their aggregate commitment by an average 2.4 GtCO2e yr–1. Of the possible explanations for this overachievement, ‘hot-air’ was estimated at 2.2 GtCO2e yr–1, while accounting rules for land use, land-use change and forestry (LULUCF) further removed 0.4 GtCO2e yr–1 from the net result excluding LULUCF. The hypothetical participation of the US and Canada would have reduced this overachievement by a net 1 GtCO2e yr–1. None of these factors – some of which may be deemed illegitimate – would therefore on its own have led to global non-compliance, even without use of the 0.3 GtCO2e of annual emissions reductions generated by the Clean Development Mechanism. The impact of domestic policies and ‘carbon leakage’ – neither of which is quantitatively assessed here – should not be neglected either.
Policy relevance
Given the ongoing evolution of the international climate regime and the adoption of the Paris Agreement in December 2015, we believe that there is a need to evaluate the results of the first commitment period of the Kyoto Protocol. To our knowledge there has been no overarching quantitative ex post assessment of the Kyoto Protocol based on the final emissions data for 2008–2012, which became available in late 2015. This article attempts to fill this gap, focusing on the domestic and international compliance of the Parties to the Kyoto Protocol in the first commitment period. 相似文献
This article assesses the relevance of ex post transaction costs in the choice of climate policy instruments in the EU (focusing mainly on the example of Germany) and the US. It reviews all publicly available empirical ex post transaction cost studies of climate policy instruments broken down by the main private and public sector cost factors and offers hypotheses on how these factors may scale depending on instrument design and other contextual factors. The key finding from the evaluated schemes is that it is possible to reject the hypothesis that asymmetries in ex post transaction costs across instruments are large and, thus, play a pivotal role in climate policy instrument choice. Both total and relative ex post transaction costs can be considered low. This conjecture differs from the experience in other areas of environmental policy instruments where high total transaction costs are considered to be important factors in the overall assessment of optimal environmental policy choice. Against this background, the main claim of this article is that in climate policy instrument choice, ex post transaction cost considerations play a minor role in large countries that feature similar institutional characteristics as the EU and the US. Rather, the focus should be on the efficiency properties of instruments for incentivizing abatement, as well as equity and political economy considerations (and other societally relevant objectives). In order to inform transaction cost considerations in climate policy instrument choice in countries that adopt new climate policies, more data would be desirable in order to enable more robust estimates of design- and context-specific transaction-cost scaling factors.
Policy relevance
The findings of this study can help inform policy makers who plan to set up novel climate policy instruments. The results indicate that ex post transaction costs play a minor role for large countries that feature similar institutional characteristics as the EU and the US. For instrument design the focus should rather be on efficiency properties of instruments in incentivizing abatement, as well as equity and political economy considerations (and other societally relevant objectives). 相似文献
This study is Part II of a series that documents the development of a suite of calibration reference materials for in situ SIMS analysis of stable isotope ratios in Ca‐Mg‐Fe carbonates. Part I explored the effects of Fe2+ substitution on SIMS δ18O bias measured from the dolomite–ankerite solid solution series [CaMg(CO3)2–CaFe(CO3)2], whereas this complementary work explores the compositional dependence of SIMS δ13C bias (calibrated range: Fe# = 0.004–0.789, where Fe# = molar Fe/(Mg+Fe)). Under routine operating conditions for carbonate δ13C analysis at WiscSIMS (CAMECA IMS 1280), the magnitude of instrumental bias increased exponentially by 2.5–5.5‰ (session‐specific) with increasing Fe‐content in the dolomite structure, but appeared insensitive to minor Mn substitution [< 2.6 mole % Mn/(Ca+Mg+Fe+Mn)]. The compositional dependence of bias (i.e., the matrix effect) was expressed using the Hill equation, yielding calibration residual values ≤ 0.3‰ relative to CRM NBS‐19 for eleven carbonate reference materials (6‐μm‐diameter spot size measurements). Based on the spot‐to‐spot repeatability of a drift monitor material that ‘bracketed’ each set of ten sample‐spot analyses, the analytical precision was ± 0.6–1.2‰ (2s, standard deviations). The analytical uncertainty for individual sample analyses was approximated by combining the precision and calibration residual values (propagated in quadrature), suggesting an uncertainty of ± 1.0–1.5‰ (2s). 相似文献
Mangrove forests are ecologically important and carbon-rich coastal ecosystems that provide direct and indirect livelihood support for coastal communities. In recent years there has been increased discussion in the policy and scientific communities over how to include mangrove forests in climate change mitigation initiatives such as REDD+. There are a number of challenges to establishing a successful REDD+ project in mangrove areas, with land tenure and stakeholder entitlements arguably the most challenging. This study examines how REDD+ approaches might be applied to better balance timber production and conservation objectives in the Matang Mangrove Forest Reserve (MMFR), a 40,466 ha mangrove forest area in Malaysia. Stakeholder profiles and needs are linked with ecosystem services to develop an integrated profile of this complex social-ecological system, which has been managed for timber production for more than 100 years, and has recently revealed evidence of declining ecosystem health. The results provide insights into how REDD+ might be operationalised in existing forest areas with traditions of multiple uses, potentially contributing to improved social-ecological outcomes for forests and their diverse stakeholders. 相似文献
Understanding the mechanisms responsible for long-term storage of organic carbon (OC) in marine environment is important for studying the marine carbon cycling and predicting how the global carbon cycle will respond to climate change. It is estimated that more than 20% of the OC in marine sediments is associated with iron oxides and thus these complexes are one of the most important factors in the long-term storage of OC. The OC-iron oxide (OC-Fe) association can be formed through either adsorption or co-precipitation, but the dominant mechanism of OC-Fe association in marine environments is co-precipitation. The combination of OC from different sources with iron oxides is selective. Iron oxides preferentially combine with marine OC in most marine environments, but in estuarine delta regions they prefer terrestrial OC. Due to large inputs of terrestrial materials, high primary production and frequent re-suspension, estuarine and marginal seas are suitable sites for OC-Fe association studies, which should be emphasized in the future. 相似文献