All adrift: aviation,shipping, and climate change policy     

Alice Bows-Larkin 《Climate Policy》2013,13(6):681-702

All sectors face decarbonization for a 2 °C temperature increase to be avoided. Nevertheless, meaningful policy measures that address rising CO₂ from international aviation and shipping remain woefully inadequate. Treated with a similar approach within the United Nations Framework Convention on Climate Change (UNFCCC), they are often debated as if facing comparable challenges, and even influence each others’ mitigation policies. Yet their strengths and weaknesses have important distinctions. This article sheds light on these differences so that they can be built upon to improve the quality of debate and ensuing policy development. The article quantifies ‘2 °C’ pathways for these sectors, highlighting the need for mitigation measures to be urgently accelerated. It reviews recent developments, drawing attention to one example where a change in aviation mitigation policy had a direct impact on measures to cut CO₂ from shipping. Finally, the article contrasts opportunities and barriers towards mitigation. The article concludes that there is a portfolio of opportunities for short- to medium-term decarbonization for shipping, but its complexity is its greatest barrier to change. In contrast, the more simply structured aviation sector is pinning too much hope on emissions trading to deliver CO₂ cuts in line with 2 °C. Instead, the solution remains controversial and unpopular – avoiding 2 °C requires demand management.

Policy relevance

The governance arrangements around the CO₂ produced by international aviation and shipping are different from other sectors because their emissions are released in international airspace and waters. Instead, through the Kyoto Protocol, the International Civil Aviation Authority (ICAO) and the International Maritime Organization (IMO) were charged with developing policies towards mitigating their emissions. Slow progress to date, coupled with strong connections with rapidly growing economies, has led to the CO₂ from international transport growing at a higher rate than the average rate from all other sectors. This article considers this rapid growth, and the potential for future CO₂ growth in the context of avoiding a 2 °C temperature rise above pre-industrial levels. It explores similarities and differences between these two sectors, highlighting that a reliance on global market-based measures to deliver required CO₂ cuts will likely leave both at odds with the overarching climate goal.  相似文献   

WAVERYS: a CMEMS global wave reanalysis during the altimetry period     

Law-Chune  Stéphane  Aouf  Lotfi  Dalphinet  Alice  Levier  Bruno  Drillet  Yann  Drevillon  Marie 《Ocean Dynamics》2021,71(3):357-378

Ocean Dynamics - As part of the Copernicus Marine Service, WAVERYS is the multi-year wave reanalysis that provides global wave data with a fine grid resolution of 1/5°. This wave reanalysis...  相似文献   

Distinguished Service Award: Dr Paul Ashley Keown     

Lex Chalmers 《New Zealand geographer》2013,69(1):64-64

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When is star formation episodic? A delay differential equation 'negative feedback' model     

Alice C. Quillen  Joss Bland-Hawthorn 《Monthly notices of the Royal Astronomical Society》2008,386(4):2227-2234

We introduce a differential equation for star formation in galaxies that incorporates negative feedback with a delay. When the feedback is instantaneous, solutions approach a self-limiting equilibrium state. When there is a delay, even though the feedback is negative, the solutions can exhibit cyclic and episodic solutions. We find that periodic or episodic star formation only occurs when two conditions are satisfied. First the delay time-scale must exceed a cloud consumption time-scale. Secondly, the feedback must be strong. This statement is quantitatively equivalent to requiring that the time-scale to approach equilibrium be greater than approximately twice the cloud consumption time-scale. The period of oscillations predicted is approximately four times the delay time-scale. The amplitude of the oscillations increases with both feedback strength and delay time.
We discuss applications of the delay differential equation (DDE) model to star formation in galaxies using the cloud density as a variable. The DDE model is most applicable to systems that recycle gas and only slowly remove gas from the system. We propose likely delay mechanisms based on the requirement that the delay time is related to the observationally estimated time between episodic events. The proposed delay time-scale accounting for episodic star formation in galaxy centres on periods similar to   P ∼ 10 Myr  , irregular galaxies with   P ∼ 100 Myr  , and the Milky Way disc with   P ∼ 2  Gyr, could be that for exciting turbulence following creation of massive stars, that for gas pushed into the halo to return and interact with the disc and that for spiral density wave evolution, respectively.  相似文献   

Flow-induced vegetation uprooting in a meandering bend:Experimental investigation     

Donatella Termini  Alice Di Leonardo 《国际泥沙研究》2022,37(3):399-410

Vegetation uprooting is a complex process which depends on many interrelated factors. In this paper,attention is focused on the flow-induced uprooting in river bends, where the flow characteristics vary as effected by the channel’s curvature and its continuous changing in the downstream direction. Results are presented by an experimental work done in a high-amplitude meandering flume with mature herbaceous vegetation on the bed. In the first part of the paper, the variation along the bend of the...  相似文献   

Using in situ cosmogenic 10Be to identify the source of sediment leaving Greenland          下载免费PDF全文

Alice H. Nelson  Paul R. Bierman  Jeremy D. Shakun  Dylan H. Rood 《地球表面变化过程与地形》2014,39(8):1087-1100

We use the concentration of in situ ¹⁰Be in quartz isolated from fluvial and morainal sand to trace sediment sources and to determine the relative contribution of glacerized and deglaciated terrain to Greenland's sediment budget. We sampled along the western, eastern, and southern margins of the Greenland Ice Sheet, and collected sediment sourced from glacerized (n = 19) and non‐glacerized terrain (n = 10), from channels where sediment from glacerized and non‐glacerized terrain is mixed (n = 28), from Holocene glacial‐fluvial terraces (n = 4), and from one sand dune. In situ ¹⁰Be concentrations in sediment range from 1600 to 34 000 atoms g^‐1. The concentration of in situ ¹⁰Be in sediment sourced from non‐glacerized terrain is significantly higher than in sediment sourced from glacerized areas, in mixed channel sediment, and in terrace sediment that was deposited during the Holocene. To constrain the timing of landscape exposure for the deglaciated portion of the Narsarsuaq field area in southern Greenland, we measured in situ ¹⁰Be concentration in bedrock (n = 5) and boulder (n = 6) samples. Paired bedrock and boulder ages are indistinguishable at 1σ uncertainty and indicate rapid exposure of the upland slopes at ~10.5 ka. The isotope concentration in sediment sourced from non‐glacerized terrain is higher than in sediment sourced from glacerized terrain because the non‐glacerized landscape has been exposed to cosmic radiation since early Holocene deglaciation. Sediment from glacerized areas contains a low, but measurable concentration of ¹⁰Be that probably accumulated at depth during a prolonged period of exposure, probably before the establishment of the Greenland Ice Sheet. The concentration of ¹⁰Be in mixed fluvial sediment and in terrace sediment is low, and similar to the concentration in sediment from glacerized areas, which indicates that the Greenland Ice Sheet is the dominant source of sediment moving through the landscape outside the glacial margin in the areas we sampled. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Combining IR and X‐ray microtomography data sets: Application to Itokawa particles and to Paris meteorite     

Zelia Dionnet  Rosario Brunetto  Alice Alon‐Toppani  Stefano Rubino  Donia Baklouti  Ferenc Borondics  Anne‐Ccile Buellet  Zahia Djouadi  Andrew King  Tomoki Nakamura  Alessandra Rotundi  Christophe Sandt  David Troadec  Akira Tsuchiyama 《Meteoritics & planetary science》2020,55(7):1645-1664

In the near future, a new generation of sample return missions (Hayabusa2, OSIRIS‐REx, MMX, etc.) will collect samples from small solar system bodies. To maximize the scientific outcome of laboratory studies and minimize the loss of precious extraterrestrial samples, an analytical sequence from less destructive to more destructive techniques needs to be established. In this work, we present a combined X‐ray and IR microtomography applied to five Itokawa particles and one fragment of the primitive carbonaceous chondrite Paris. We show that this analytical approach is able to provide a 3‐D physical and chemical characterization of individual extraterrestrial particles, using the measurement of their 3‐D structure and porosity, and the detection of mineral and organic phases, and their spatial co‐localization in 3‐D. We propose these techniques as an efficient first step in a multitechnique analytical sequence on microscopic samples collected by space missions.  相似文献   

Possible effects of human impacts on epibenthic communities and coral rubble features in the marine Park of Bunaken (Indonesia)     

Federica Fava  Massimo Ponti  Alice Scinto  Barbara Calcinai  Carlo Cerrano 《Estuarine, Coastal and Shelf Science》2009

Indo-Pacific coral reefs are considered among the most complex and biodiversified ecosystems in the world. Their existence is threatened by both natural and anthropogenic factors. Therefore, the assessment of anthropogenic disturbances is necessary to protect and manage these marine natural resources. In Bunaken Marine Park (North Sulawesi, Indonesia) epibenthic assemblages and coral rubble features at four impacted sites (each of them located close to villages and frequently exploited as recreational diving spots), and four well preserved sites (far from villages and scarcely frequented by divers), were investigated at 6, 12 and 18 m depth, in order to identify possible reef modifications. The assemblages were sampled by way of photographs. Coral rubble cover was estimated both by way of photographs and along belt transects, while grain size and the living fraction of the coral rubble were assessed by direct samples. The data showed significant differences between the study sites and between depths with regard to human activity. The hard coral cover and the assemblage heterogeneity are higher in control sites than in the impacted site where, especially in shallow water, the mechanical damage can strongly affect the assemblage structure.  相似文献   

Residence times in a hypersaline lagoon: Using salinity as a tracer     

Stephen M. Mudge  John D. Icely  Alice Newton 《Estuarine, Coastal and Shelf Science》2008

Generally the waters of the Ria Formosa Lagoon, Portugal have a short residence time, in the order of 0.5 days (Tett, P., Gilpin, L., Svendsen, H., Erlandsson, C.P., Larsson, U., Kratzer, S., Fouilland, E., Janzen, C., Lee, J., Grenz, C., Newton, A., Ferreira, J.G., Fernandes, T., Scory, S., 2003. Eutrophication and some European waters of restricted exchange. Continental Shelf Research 23, 1635–1671). This estimation is based on the measurements of currents and the modelling of water exchange at the outlets to the ocean. However, observations of the temperature and salinity in the inner channels imply that residence time is greater in these regions of the lagoon. To resolve this apparent contradiction, spatial measurements of the temperature and salinity were made with a meter for conductivity, temperature and depth along the principal channels of the western portion of the lagoon, with a sampling frequency of two per second. Evaporation rates of 5.4 mm day⁻¹ were measured in a salt extraction pond adjacent to the lagoon and used to determine the residence time through salinity differences with the incoming seawater. In June 2004, the water flooding in from the ocean had an average salinity of 36.07 which contrasted with a maximum of 37.82 at mid ebb on a spring tide, corresponding to a residence time of >7 days; the mean residence time was 2.4 days. As the tide flooded into the channels, the existing water was advected back into the lagoon. Although there was a small amount of mixing with water from another inlet, the water body from the inner lagoon essentially remained distinct with respect to temperature and salinity characteristics. The residence time of the water was further prolonged at the junction between the main channels, where distinct boundaries were observed between the different water masses. As the water ebbed out, the shallow Western Channel was essentially isolated from the rest of the outer lagoon, and the water from this channel was forced down the Ramalhete Channel, from where it was unable to exit the lagoon in one tidal cycle due to the extensive path length of ∼14 km to the sea.  相似文献   

Population statistics study of radio and gamma-ray pulsars in the Galactic plane     

Peter L. Gonthier  Sarah A. Story  Brian D. Clow  Alice K. Harding 《Astrophysics and Space Science》2007,309(1-4):245-251

We present results of our pulsar population synthesis of normal and millisecond pulsars in the Galactic plane. Over the past several years, a program has been developed to simulate pulsar birth, evolution and emission using Monte Carlo techniques. We have added to the program the capability to simulate millisecond pulsars, which are old, recycled pulsars with extremely short periods. We model the spatial distribution of the simulated pulsars by assuming that they start with a random kick velocity and then evolve through the Galactic potential. We use a polar cap/slot gap model for γ-ray emission from both millisecond and normal pulsars. From our studies of radio pulsars that have clearly identifiable core and cone components, in which we fit the polarization sweep as well as the pulse profiles in order to constrain the viewing geometry, we develop a model describing the ratio of radio core-to-cone peak fluxes. In this model, short period pulsars are more cone-dominated than in our previous studies. We present the preliminary results of our recent study and the implications for observing these pulsars with GLAST and AGILE.   相似文献