Carbon dioxide removal (sometimes called carbon removal or CDR) refers to a cluster of technologies, practices and approaches that remove and sequester carbon dioxide from the atmosphere. Despite the common denominator of removing carbon dioxide, these technologies can be very different.
The reduction of anthropogenic greenhouse gas emission rates alone appears insufficient to limit the rise in global temperatures. Negative Emission Technologies (NETs) can be helpful in this critical goal by actively removing CO2 from the atmosphere. Industrialised countries like Scotland will require NETs to address their climate targets and reach net-zero carbon emissions in a timely manner. However, the implementation of NETs has varied energy, economic and environmental implications that need to be analysed in detail. In this paper, we explore the potential energy and economic costs for implementation of land-based NETs in Scotland. This analysis is based on the calculated averaged costs of the different technologies and the availability of resources for its implementation in Scotland. We found that the country has a maximum technical potential to abate 90–100% of its annual CO2 emissions by means of land-based NETs, thanks to its low annual emissions and large land area for implementation of NETs. Even in less optimistic scenarios, Scotland is exceptionally well suited for land NETs, which can complement and enhance the potential of more conventional technologies, like renewable energy resources. Our results show that Scotland could lead the transformation towards a carbon-neutral society.
<p>Achieving climate-smart nutrition security in sub-Saharan Africa is an urgent challenge due to increasing climate risks to agricultural production, population growth and food price volatility This necessitates an integrated evidence base that takes into account not only future food system modelling but stakeholder knowledge and the plausible and desirable transformations that these information streams can provide. Accordingly, we use the integrated Future Estimator for Emissions and Diets (iFEED) to explore scenarios of food system transformation towards nutrition security in Zambia. iFEED integrates climate, crop and land use modelling to explore scenarios of relevance to the Zambian policy landscape, as informed by stakeholders. Four scenarios were defined by stakeholders, based on the extent of market connectivity and technological development, and the level of climate risk. Analysis of cross-scenario implications shows that diversification of agricultural production away from maize and towards more nutrient-dense foods is necessary to achieve nutrition security by mid-century, and that agricultural areas must expand unless yield improvements are faster than seen historically. These transformative changes could result in increased greenhouse gas emissions, which may be a necessary trade-off given the need to ensure nutrition security. We also present results from further analysis that shows how crop diversification and irrigation – both identified as key policy topic areas for Zambia – can contribute to building resilience in the face of increasing climate extremes. Results show that irrigation can help to reduce the interannual variability of food production by mid-century – and hence improve nutrition security in an increasingly volatile future climate. Crop diversification also helps to build resilience through crop risk-spreading, and also increases average production. Whilst these transformations are challenging to achieve, the alternative for a nutrition-secure future is to rely increasingly on imports, which would be economically and politically challenging given the large import increases required.</p>
Is the Labour Party destined to become simply a stage army of loyalists? Pete Smith looks at the implications for Labour and the other political parties.
The international pharmaceutical regulatory academic and industrial toxicology communities are collaborating to improve the efficiency and effectivenes s of cancer hazard identification based on dramatic improvements in our understanding of the cancer process. Guidelines emanating from the International Conference on Harmonization provide for use of in vivo alternatives. Standard practices utilizing lifetime rat and mouse studies are recognized as seriously flawed with over 80% false positive rates. Furthermore, tobacco, the most important human carcinogen commercialized by industry, is negative in these traditional lifetime studies. The lifetime mouse bioassay is generally recognized in pharmaceutical development as not adding value in safety assessment. An international consortium under the aegis of ILSI has recently completed an evaluation of alternative mouse cancer models. Transgenic models are less expensive, use fewer animals and take less time than traditional lifetime bioassays. These alternative models have now been sufficiently evaluated to be considered useful in the safety assessment plan for pharmaceuticals in development. Specifically for example, the rasH2 appears useful in detecting nongenotoxic as well as genotoxic rodent tumorigens with improved concordance with human response. The p53 +/- heterozygous mouse apparently identifies hormonal carcinogenic mechanisms, immunosuppressive carcinogens, and genotoxic carcinogens. The TG:AC predicts for rodent tumorigens applied topically. Recent experiences at FDA, CPMP, and MHW indicate that with good planning and agency interactions, regulatory acceptability can be anticipated.
Abstract When planning sampling in an experiment where soil organic carbon (SOC) content is expected to change, it is necessary to know how many samples will need to be taken to demonstrate a change in SOC and after how long this change will be detectable. Much has been published on the number of samples required to demonstrate the minimum detectable difference in SOC, but less on how long it takes for this change to be detectable. In this paper, a model of SOC dynamics is used to estimate the minimum time taken for a change in total SOC content to become measurable under different carbon inputs, land uses and soil types. For free air carbon dioxide enrichment (FACE), and other experiments in which SOC is expected to increase, relationships between the percentage change in C inputs and the time taken to measure a change in SOC are presented, for two levels of sampling intensity corresponding to the maximum that is practically possible in most experiments (∼100 samples) and that used regularly in field experiments (10–20 samples). In FACE experiments, where C inputs increase by a maximum of about 20–25%, SOC change could be detected with 90% confidence after about 6–10 years if a sampling regime allowing 3% change in background SOC level (probably requiring a very large number of samples) were used, but could not be detected at all if a sampling regime were used that allowed only a 15% change in background SOC to be detected. If increases in C inputs are much below 15%, it might not be possible to detect a change in soil C without an enormous number of samples. Relationships between the change in C inputs and the time taken to measure a change in SOC are robust over a range of soil types and land uses. The results demonstrate how models of SOC dynamics can be used to complement statistical power analyses for planning when, and how intensively, to sample soils during experiments. An advantage of the modelling approach demonstrated here is that estimates of the minimum time taken for a change in soil carbon to become detectable can be made, even before any detailed soil samples are taken, simply from estimates of the likely increase in carbon inputs to the soil (via expected changes in net primary production).
The world's soils contain approximately 1500 Pg (1 Pg = 1 Gt = 1015 g) of organic carbon (Batjes, 1996), roughly three times the amount of carbon in vegetation and twice the amount in the atmosphere (IPCC, 2001; Denman et al., 2007). The annual fluxes of CO2 from atmosphere to land (global net primary productivity, NPP) and land to atmosphere (respiration and fire) are of the order of 60 Pg C y−1 (IPCC, 2000b). During the 1990s, fossil fuel combustion and cement production emitted 6.4 ± 1.3 Pg C y−1 to the atmosphere, while land-use change emitted 1.6 ± 0.8 Pg C y−1. Atmospheric carbon increased at a rate of 3.2 ± 0.1 Pg C y−1, the oceans absorbed 2.3 ± 0.8 Pg C y−1 and there was an estimated terrestrial sink of 2.6 ± 1.3 Pg C y−1 (Schimel et al., 2001; Denman et al., 2007). The amount of carbon stored in soils globally is therefore large compared to gross and net annual fluxes of carbon to and from the terrestrial biosphere, and the pools of carbon in the atmosphere and vegetation. Because of this, increasing the size of the global soil carbon pool by even a small proportion has the potential to sequester large amounts of carbon, and thus soils have an important role to play in mitigating climate change.
