Grazed grassland systems are an important component of the global carbon cycle and also influence global climate change through their emissions of nitrous oxide and methane. However, there are huge uncertainties and challenges in the development and parameterisation of process-based models for grazed grassland systems because of the wide diversity of vegetation and impacts of grazing animals. A process-based biogeochemistry model, DeNitrification-DeComposition (DNDC), has been modified to describe N₂O emissions for the UK from regional conditions. This paper reports a new development of UK-DNDC in which the animal grazing practices were modified to track their contributions to the soil nitrogen (N) biogeochemistry. The new version of UK-DNDC was tested against datasets of N₂O fluxes measured at three contrasting field sites. The results showed that the responses of the model to changes in grazing parameters were generally in agreement with observations, showing that N₂O emissions increased as the grazing intensity increased.

Traditionally, life cycle assessment (LCA) does not estimate a key property: surface albedo. Here an enhancement of the LCA methodology has been proposed through the development and employment of a time-dependent climatological model for including the effect of surface albedo on climate. The theoretical findings derived by the time-dependent model have been applied to the case study of a black and a white roof evaluated in the time-frames of 50 and 100 years focusing on the impact on global warming potential. The comparative life cycle impact assessment of the two roofs shows that the high surface albedo plays a crucial role in offsetting radiative forcings. In the 50-year time horizon, surface albedo is responsible for a decrease in CO₂eq of 110–184 kg and 131–217 kg in 100 years. Furthermore, the white roof compared to the black roof, due to the high albedo, decreases the annual energy use of about 3.6–4.5 kWh/m².

Hydrochemical sampling of South Pennine (UK) headwater streams draining eroded upland peatlands demonstrates these systems are nitrogen saturated, with significant leaching of dissolved inorganic nitrogen (DIN), particularly ammonium, during both stormflow and baseflow conditions. DIN leaching at sub-catchment scale is controlled by geomorphological context; in catchments with low gully densities ammonium leaching dominates whereas highly gullied catchments leach ammonium and nitrate since lower water tables and increased aeration encourages nitrification. Stormflow flux calculations indicate that: approximately equivalent amounts of nitrate are deposited and exported; ammonium export significantly exceeds atmospheric inputs. This suggests two ammonium sources: high atmospheric loadings; and mineralisation of organic nitrogen stored in peat. Downstream trends indicate rapid transformation of leached ammonium into nitrate. It is important that low-order headwater streams are adequately considered when assessing impacts of atmospheric loads on the hydrochemistry of stream networks, especially with respect to erosion, climate change and reduced precipitation.

Nitrous oxide (N₂O) emissions from Phragmites australis (reed) – dominated zones in Baiyangdian Lake, the largest shallow lake of Northern China, were investigated under different hydrological conditions with mesocosm experiments during the growing season of reeds. The daily and monthly N₂O emissions were positively correlated with air temperature and the variation of aboveground biomass of reeds (p < 0.05), respectively. The N₂O emissions from reeds were about 45.8–52.8% of that from the sediments. In terms of the effect of hydrological conditions, N₂O emissions from the aquatic-terrestrial ecotone were 9.4–26.1% higher than the submerged zone, inferring that the variation of water level would increase N₂O emissions. The annual N₂O emission from Baiyangdian Lake was estimated to be about 114.2 t. This study suggested that N₂O emissions from shallow lakes might be accelerated by the climate change as it has increased air temperature and changed precipitation, causing the variation of water level.

The pH change and the release of organic matter and metals from sediment, due to the potential CO₂ acidified seawater leakages from a CCS (Carbon Capture and Storage) site are presented. Column leaching test is used to simulate a scenario where a flow of acidified seawater is in contact with recent contaminated sediment. The behavior of pH, dissolved organic carbon (DOC) and metals As, Cd, Cr, Cu, Ni, Pb, Zn, with liquid to solid (L/S) ratio and pH is analyzed. A stepwise strategy using empirical expressions and a geochemical model was conducted to fit experimental release concentrations. Despite the neutralization capacity of the seawater-carbonate rich sediment system, important acidification and releases are expected at local scale at lower pH. The obtained results would be relevant as a line of evidence input of CCS risk assessment, in an International context where strategies to mitigate the climate change would be applied.

For a given emissions inventory, the general levels of air pollutants and the spatial distribution of their concentrations are determined by the physiochemical state of the atmosphere. Apart from the trivial seasonal and daily cycles, most of the variability is associated with the atmospheric synoptic scale. A simple methodology for assessing future levels of air pollutants' concentrations based on synoptic forecasts is presented. At short time scales the methodology is comparable and slightly better than persistence and seasonal forecasts at categorical classification of pollution levels. It's utility is shown for air quality studies at the long time scale of a changing climate scenario, where seasonality and persistence cannot be used. It is demonstrated that the air quality variability due to changes in the pollution emissions can be expected to be much larger than that associated with the effects of climatic changes.

The global distribution and long-range transport of polyfluoroalkyl substances (PFASs) were investigated using seawater samples collected from the Greenland Sea, East Atlantic Ocean and the Southern Ocean in 2009–2010. Elevated levels of ΣPFASs were detected in the North Atlantic Ocean with the concentrations ranging from 130 to 650 pg/L. In the Greenland Sea, the ΣPFASs concentrations ranged from 45 to 280 pg/L, and five most frequently detected compounds were perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS), perfluorohexanoic acid (PFHxA), perfluorooctane sulfonate (PFOS) and perfluorobutane sulfonate (PFBS). PFOA (15 pg/L) and PFOS (25–45 pg/L) were occasionally found in the Southern Ocean. In the Atlantic Ocean, the ΣPFASs concentration decreased from 2007 to 2010. The elevated PFOA level that resulted from melting snow and ice in Greenland Sea implies that the Arctic may have been driven by climate change and turned to be a source of PFASs for the marine ecosystem.

Recent changes in ocean temperature have impacted marine ecosystem function globally. Nevertheless, the responses have depended upon the rate of change of temperature and the season when the changes occur, which are spatially variable. A rigorous statistical analysis of sea surface temperature observations over 25years was used to examine spatial variability in overall and seasonal temperature trends within the wider Caribbean. The basin has experienced high spatial variability in rates of change of temperature. Most of the warming has been due to increases in summer rather than winter temperatures. However, warming was faster in winter in the Loop Current area and the south-eastern Caribbean, where the annual temperature ranges have contracted. Waters off Florida, Cuba and the Bahamas had a tendency towards cooling in winter, increasing the amplitude of annual temperature ranges. These detailed patterns can be used to elucidate ecological responses to climatic change in the region.

The keynote paper by Garrett Hardin 44years ago introduced the term ‘tragedy of the commons’ into our language (Hardin, 1968); this term is now used widely, but it is neither universally accepted nor fully understood. Irrespective, the ‘tragedy of the commons’ is an increasing reality for more than 500 million people that rely on the biodiversity resources and services of tropical coral reefs, mangrove forests, seagrass beds and associated fisheries. These natural resources continue to decline despite major advances in our scientific understanding of how ecosystems and human populations interact, and the application of considerable conservation and management efforts at scales from local user communities to oceans. Greater effort will be required to avert increasing damage from over-exploitation, pollution and global climate change; all deriving from increasing exploitation driven by poverty and progress i.e. continuing to expand development indefinitely and extraction of resources at industrial scales. However, the ‘tragedy’ concept has been widely criticized as a simple metaphor for a much larger set of problems and solutions. We argue that the ‘tragedy’ is essentially real and will continue to threaten the lives of millions of people unless there are some major moral and policy shifts to reverse increasing damage to coastal habitats and resources. We agree with the conclusion by Hardin that the solution to the tragedy will not be through the application of natural sciences, but via implementing exceedingly difficult and controversial moral decisions. An extreme example of a moral and controversial direction suggested by Hardin was in re-examining the ‘freedom to breed’ as an inherent human value. The need for ‘moral decisions’ is even greater in 2012.