National Inventories of Terrestrial Carbon Sources and Sinks: The U.K. Experience

The U.K. has extensive databases on soils, land cover and historic land use change which have made it possible to construct a comprehensive inventory of the principal terrestrial sources and sinks of carbon for approximately the year 1990, using methods that are consistent with, and at least as accurate as, the revised 1996 guidelines recommended by IPCC where available – and including categories which are not currently considered under the UN Framework Convention on Climate Change. This country inventory highlights issues concerning methodology, uncertainty, double counting, the importance of soils and the relative magnitude of sources and sinks which are reported to the UNFCCC relative to other sources and sinks. The carbon sinks (negative values in MtC a^-1) for categories reported to the UNFCCC, based on the IPCC categories, were estimated to be: forest trees and litter (–2.1), U.K. forest products (–0.5, ignoring imports and exports), non-forest biomass (–0.3), forest soils (–0.1) and soils on set-aside land (–0.4). The carbon sources (positive values) reported under the UNFCCC were estimated to be: losses of soil organic carbon resulting from cultivation of semi-natural land (6.2) and from urbanization (1.6), drainage of peatlands (0.3) and fenlands (0.5), and peat extraction (0.2). A range of other sources and sinks not covered by the IPCC guidelines were also quantified, namely, the accumulation of carbon in undrained peatlands (–0.7, ignoring methane emission), sediment accretion in coastal marshes (–0.1), the possible U.K. share of the CO₂ and N fertilization carbon sink (–2.0) and riverine organic and particulate carbon export to the sea (1.4, which may be assumed to be a source if most of this carbon is released as CO₂ in the sea). All sinks totalled –6.2 and sources 10.2, giving a net flux to the atmosphere in 1990 of 4.0 MtC a^-1. Uncertainties associated with categories, mostly based on best guesses, ranged from ±15% for forest biomass and litter to ±60% for CO₂ and N fertilization.     

Community volunteer assessment of recreational water quality in the Hutt River,Wellington

ABSTRACT

Water is an important component of many recreational opportunities and New Zealand invests significant resources in recreational water quality (RWQ) monitoring to assess risks to public health. However, monitoring primarily focuses on microbiological hazards and RWQ is considerably broader than this. The goal of this study was to take a comprehensive approach to evaluating RWQ while exploring the potential for greater public involvement in monitoring. A popular river swimming site was co-monitored weekly by volunteers and a council field officer. The attributes monitored–water temperature, visual clarity, benthic cyanobacteria and filamentous periphyton cover, E. coli and rubbish–were identified from a volunteer workshop. There was good concordance between volunteer and council data suggesting that volunteer measurements can be considered reliable. This highlights the potential for volunteers, with professional support, including training and quality assurance, to extend council RWQ surveillance to additional monitoring sites while improving public engagement on water management.     

Measurement of vertical distribution of isoprene in surface seawater, its chemical fate, and its emission from several phytoplankton monocultures

Concurrent measurements of isoprene (2-methyl-1,3-butadiene) in seawater together with atmospheric concentrations in the Gulf Stream off the Florida coast were made. Florida Straits surface water concentrations of isoprene varied between 9.8 and 50.8 pmol 1⁻¹. Surface water isoprene concentrations showed a positive correlation with measured chlorophyll fluorescence, consistent with the biogenic origin of this non-methane hydrocarbon. Depth profiles showed a maximum in isoprene concentration similar to that of biological productivity as indicated by chlorophyll fluorescence. Daytime atmospheric mixing ratios of isoprene were never above 11 parts-per-trillion (pptv) and eight of eleven samples taken were below the ˜ 5 pptv detection limit. Using an estimated value of the Henry's law constant (K_H ˜ 3.1) a supersaturation of surface seawater of 2 to 3 orders of magnitude is estimated.Laboratory grown monocultures of several common phytoplankton species showed production of isoprene. Processes controlling the isoprene concentration in the photic zone of the ocean and the marine boundary layer are discussed. A calculation using a simple time dependent photochemical box model confirmed that isoprene is rapidly consumed by its reaction with the OH radical in the marine atmosphere.     

Relative sea‐level change and postglacial isostatic adjustment along the coast of south Devon,United Kingdom

Previous sea‐level studies suggest that southwest Britain has the fastest subsiding coastline in the United Kingdom, but tide‐gauge data, GPS and gravity measurements and geophysical models show little evidence of anomalous subsidence in this region. In this paper we present 15 new sea‐level index points from four coastal barrier systems in south Devon. Eight are from compaction‐free basal sediments and others were corrected for autocompaction. Our data suggest that relative sea level along the south Devon coastline has risen by 21 ± 4 m during the past 9000 years. Sea‐level rise slowed during the middle and late Holocene and a rise of 8 ± 1 m has occurred since ca. 7000 cal. yr BP. Anomalous ages for many rejected points are attributed to sediment reworking during barrier transgression. The relative sea‐level history during the early and middle Holocene shows a good fit with geophysical model predictions, but the geological and modelled data diverge in the later Holocene. Unlike the geophysical models, sea‐level index points cannot differentiate between late Holocene relative sea‐level histories of south Devon and southwest Cornwall. It is suggested that this discrepancy can be resolved by obtaining additional high‐quality sea‐level index points covering the past 4000 years. Copyright © 2008 John Wiley & Sons, Ltd.     

An improved glacial isostatic adjustment model for the British Isles

The glacial isostatic adjustment (GIA) of the British Isles is of interest due to the constraints that can be provided on key model parameters such as the global meltwater signal, local ice sheet history and viscoelastic earth structure. A number of recent studies have modelled relative sea‐level (RSL) data from this region to constrain model parameters. As indicated in these studies, the sensitivity of these data to both local and global parameters results in a highly non‐unique problem. This study aims to address this inherent non‐uniqueness by combining a previously published British–Irish ice model that is based on the most recent geomorphological data with a new global ice sheet model that provides an accurate prediction of eustatic sea‐level change. In addition, constraints from Global Positioning System (GPS) measurements of present‐day vertical land motion are considered alongside the entirety of RSL data from both Great Britain and Ireland. A model solution is found that provides a high‐quality fit to both the RSL data and the GPS data. Within the range of earth viscosity values considered, the optimal data model fits were achieved with a relatively thin lithosphere (71 km), upper mantle viscosities in the range 4–6 × 10²⁰ Pa s and lower mantle viscosities ≥ 3 × 10²² Pa s. Copyright © 2011 John Wiley & Sons, Ltd.     

Unravelling property relations around forest carbon

Market‐based interventions to Reduce Emissions from Deforestation and Forest Degradation (REDD+) enable the carbon stored in land and forests to be traded as a new and intangible form of property. Using examples from Cambodia, the Philippines and Papua New Guinea, we examine the property negotiations underpinning this new forest carbon economy. We show that the institutions and land use negotiations needed to ‘produce’ forest carbon interact recursively with existing property claims over land and forests. Even where customary rights are formally recognized (PNG, Philippines), claims to forest carbon are still complicated by ambiguities and complexities surrounding rights to forested land. Meanwhile the new value attached to forest carbon can stimulate efforts to appropriate land and forest resources associated with it, creating new power relations and property dynamics. This interplay between forest carbon and underlying contested property claims in rural forest settings creates an unstable basis for forest carbon markets and raises questions about future access to forested land.