The impact of surplus units from the first Kyoto period on achieving the reduction pledges of the Cancún Agreements     

Michel G. J. den Elzen  Malte Meinshausen  Andries F. Hof 《Climatic change》2012,114(2):401-408

Countries with emission levels below their emission allowances have surplus Assigned Amount Units (AAUs) or other emission credits. Under the Kyoto Protocol, these surplus credits may effectively be carried from the first to a following commitment period. In the climate negotiations, various rules for carry-over and sale of surplus allowances have been put forward. This paper analyses the effect of these options on the reduction pledges for 2020, taking into account the estimated credits from the Clean Development Mechanism, Joint Implementation projects, and land-use activities for the first commitment period. For current Kyoto Protocol rules of unlimited carry-over of surplus allowances and limited carry-over of other credits, the environmental effectiveness of reduction pledges could be seriously undermined. For the group of countries that showed a willingness to participate in a second commitment period, it could imply that instead of an aggregated 2020 target resulting from the pledges of 18 to 28?% below 1990 levels by 2020, their emissions could return to business-us-usual emission projections. For the EU, a 30?% target by 2020 could imply higher emissions compared to a 20?% target, if surplus allowances would be used for achieving the 30?% but not for the 20?% target. Restricting the use of Kyoto surplus units to domestic use only, would limit the problem, but still seriously undermine the effectiveness of 2020 reduction targets.  相似文献   

The role of the land use, land use change and forestry sector in achieving Annex I reduction pledges   总被引：2，自引：2，他引：0  

Giacomo Grassi  Michel G. J. den Elzen  Andries F. Hof  Roberto Pilli  Sandro Federici 《Climatic change》2012,115(3-4):873-881

Annex I Parties may receive credits or debits from Land Use, Land Use Change and Forestry (LULUCF) activities, contributing to achieving individual emission reduction targets. In the Durban climate negotiations, Parties agreed new LULUCF accounting rules for the second commitment period of the Kyoto Protocol (CP2). By using these new rules, this paper presents key differences among Parties at the minimum (assuming no additional action) and potential (assuming additional actions) contribution of the forest-related LULUCF activities in achieving the pledges for 2020. Overall, the potential contribution of LULUCF is relatively modest (up to about 2 % of 1990 emissions) for the EU, the Annex I Parties likely joining the CP2, and for the Annex I Parties that joined the CP1 as a whole. However, for specific Parties, LULUCF can make a substantial contribution to achieving the pledges. For New Zealand, for instance, the potential contribution of future LULUCF credits may equal 33 % of its 1990 emission level. For Australia, the pledges are expressed relative to 2000 emission levels including LULUCF emissions. Given that LULUCF emissions have strongly declined between 1990 and 2000, and a further decline in foreseen by 2020 (based on Australia’s projections), the minimum contribution of LULUCF to meet the Australian pledges appears to be about 19 % and 7 % relative to its 1990 and 2000 emission level, respectively. A further 3 % potential contribution is estimated from additional actions.  相似文献   

Temporal and Spatial Variations of the Aerodynamic Roughness Length in the Ablation Zone of the Greenland Ice Sheet   总被引：2，自引：1，他引：1  

C. J. P. P. Smeets  M. R. van den Broeke 《Boundary-Layer Meteorology》2008,128(3):315-338

To understand the response of the Greenland ice sheet to climate change the so-called ablation zone is of particular importance, since it accommodates the yearly net surface ice loss. In numerical models and for data analysis, the bulk aerodynamic method is often used to calculate the turbulent surface fluxes, for which the aerodynamic roughness length (z ₀) is a key parameter. We present, for the first time, spatial and temporal variations of z ₀ in the ablation area of the Greenland ice sheet using year-round data from three automatic weather stations and one eddy-correlation mast. The temporal variation of z ₀ is found to be very high in the lower ablation area (factor 500) with, at the end of the summer melt, a maximum in spatial variation for the whole ablation area of a factor 1000. The variation in time matches the onset of the accumulation and ablation season as recovered by sonic height rangers. During winter, snow accumulation and redistribution by snow drift lead to a uniform value of z ₀≈ 10⁻⁴ m throughout the ablation area. At the beginning of summer, snow melt uncovers ice hummocks and z ₀ quickly increases well above 10⁻² m in the lower ablation area. At the end of summer melt, hummocky ice dominates the surface with z ₀ > 5  ×  10⁻³ m up to 60 km from the ice edge. At the same time, the area close to the equilibrium line (about 90 km from the ice edge) remains very smooth with z ₀ = 10⁻⁵ m. At the beginning of winter, we observed that single snow events have the potential to lower z ₀ for a very rough ice surface by a factor of 20 to 50. The total surface drag of the abundant small-scale ice hummocks apparently dominates over the less frequent large domes and deep gullies. The latter results are verified by studying the individual drag contributions of hummocks and domes with a drag partition model.  相似文献   

The Parameterisation of Scalar Transfer over Rough Ice     

C. J. P. P. Smeets  M. R. van den Broeke 《Boundary-Layer Meteorology》2008,128(3):339-355

We test a surface renewal model that is widely used over snow and ice surfaces to calculate the scalar roughness length (z _s ), one of the key parameters in the bulk aerodynamic method. For the first time, the model is tested against observations that cover a wide range of aerodynamic roughness lengths (z ₀). During the experiments, performed in the ablation areas of the Greenland ice sheet and the Vatnajökull ice cap in Iceland, the surface varied from smooth snow to very rough hummocky ice. Over relatively smooth snow and ice with z ₀ below a threshold value of approximately 10^?3 m, the model performs well and in accord with earlier studies. However, with growing hummock size, z ₀ increases well above the threshold and the bulk aerodynamic flux becomes significantly smaller than the eddy-correlation flux (e.g. for z ₀ = 0.01 m, the bulk aerodynamic flux is about 50% smaller). Apparently, the model severely underpredicts z _s over hummocky ice. We argue that the surface renewal model does not account for the deep inhomogeneous roughness sublayer (RSL) that is generated by the hummocks. As a consequence, the homogeneous substrate ice grain cover becomes more efficiently ‘ventilated’. Calculations with an alternative model that includes the RSL and was adapted for use over hummocky ice, qualitatively confirms our observations. We suggest that, whenever exceedance of the threshold occurs (z ₀  >  10^?3 m, i.e., an ice surface covered with at least 0.3-m high hummocks), the following relation should be used to calculate scalar roughness lengths, ln (z _s /z ₀)  =  1.5  ? 0.2 ln (Re _*)  ? 0.11(ln (Re _*))².  相似文献   

Climate benefits of changing diet   总被引：3，自引：3，他引：0  

Elke Stehfest  Lex Bouwman  Detlef P. van Vuuren  Michel G. J. den Elzen  Bas Eickhout  Pavel Kabat 《Climatic change》2009,95(1-2):83-102

Climate change mitigation policies tend to focus on the energy sector, while the livestock sector receives surprisingly little attention, despite the fact that it accounts for 18% of the greenhouse gas emissions and for 80% of total anthropogenic land use. From a dietary perspective, new insights in the adverse health effects of beef and pork have lead to a revision of meat consumption recommendations. Here, we explored the potential impact of dietary changes on achieving ambitious climate stabilization levels. By using an integrated assessment model, we found a global food transition to less meat, or even a complete switch to plant-based protein food to have a dramatic effect on land use. Up to 2,700 Mha of pasture and 100 Mha of cropland could be abandoned, resulting in a large carbon uptake from regrowing vegetation. Additionally, methane and nitrous oxide emission would be reduced substantially. A global transition to a low meat-diet as recommended for health reasons would reduce the mitigation costs to achieve a 450 ppm CO₂-eq. stabilisation target by about 50% in 2050 compared to the reference case. Dietary changes could therefore not only create substantial benefits for human health and global land use, but can also play an important role in future climate change mitigation policies.  相似文献   

The rise and fall of galaxy activity in dark matter haloes     

Anna Pasquali  Frank C. van den Bosch  H. J. Mo  Xiaohu Yang  Rachel Somerville 《Monthly notices of the Royal Astronomical Society》2009,394(1):38-50

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Effects of pipe outlet blocking on hydrological functioning in a degraded blanket peatland     

Taco H. Regensburg  Pippa J. Chapman  Michael G. Pilkington  David M. Chandler  Martin G. Evans  Joseph Holden 《水文研究》2021,35(3):e14102

Peatland restoration practitioners are keen to understand the role of drainage via natural soil pipes, especially where erosion has released large quantities of fluvial carbon in stream waters. However, little is known about pipe-to-stream connectivity and whether blocking methods used to impede flow in open ditch networks and gullies also work on pipe networks. Two streams in a heavily degraded blanket bog (southern Pennines, UK) were used to assess whether impeding drainage from pipe networks alters the streamflow responses to storm events, and how such intervention affects the hydrological functioning of the pipe network and the surrounding peat. Pipeflow was impeded in half of the pipe outlets in one stream, either by inserting a plug-like structure in the pipe-end or by the insertion of a vertical screen at the pipe outlet perpendicular to the direction of the predicted pipe course. Statistical response variable η² showed the overall effects of pipe outlet blocking on stream responses were small with η² = 0.022 for total storm runoff, η² = 0.097 for peak discharge, η² = 0.014 for peak lag, and η² = 0.207 for response index. Both trialled blocking methods either led to new pipe outlets appearing or seepage occurring around blocks within 90 days of blocking. Discharge from four individual pipe outlets was monitored for 17 months before blocking and contributed 11.3% of streamflow. Pipe outlets on streambanks with headward retreat produced significantly larger peak flows and storm contributions to streamflow compared to pipe outlets that issued onto straight streambank sections. We found a distinctive distance-decay effect of the water table around pipe outlets, with deeper water tables around pipe outlets that issued onto straight streambanks sections. We suggest that impeding pipeflow at pipe outlets would exacerbate pipe development in the gully edge zone, and propose that future pipe blocking efforts in peatlands prioritize increasing the residence time of pipe water by forming surface storage higher up the pipe network.  相似文献   

Recovery of the internal orbital structure of galaxies     

G. van de Ven †  P. T. de Zeeuw  R. C. E. van den Bosch 《Monthly notices of the Royal Astronomical Society》2008,385(2):614-646

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Ongoing assembly of massive galaxies by major merging in large groups and clusters from the SDSS     

Daniel H. McIntosh †  Yicheng Guo  Jen Hertzberg ‡  Neal Katz  H. J. Mo  Frank C. van den Bosch  Xiaohu Yang 《Monthly notices of the Royal Astronomical Society》2008,388(4):1537-1556

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Geostatistics for Compositional Data: An Overview   总被引：1，自引：0，他引：1  

Tolosana-Delgado  Raimon  Mueller  Ute  van den Boogaart  K. Gerald 《Mathematical Geosciences》2019,51(4):485-526

Mathematical Geosciences - This paper presents an overview of results for the geostatistical analysis of collocated multivariate data sets, whose variables form a composition, where the components...  相似文献