Assessing carbon dioxide removal through global and regional ocean alkalinization under high and low emission pathways

Atmospheric carbon dioxide (CO2) levels continue to rise, increasing the risk of severe impacts on the Earth system, and on the ecosystem services that it provides. Artificial ocean alkalinization (AOA) is capable of reducing atmospheric CO2 concentrations and surface warming and addressing ocean acidification. Here, we simulate global and regional responses to alkalinity (ALK) addition (0.25 PmolALK yr−1) over the period 2020–2100 using the CSIRO-Mk3L-COAL Earth System Model, under high (Representative Concentration Pathway 8.5; RCP8.5) and low (RCP2.6) emissions. While regionally there are large changes in alkalinity associated with locations of AOA, globally we see only a very weak dependence on where and when AOA is applied. On a global scale, while we see that under RCP2.6 the carbon uptake associated with AOA is only ∼ 60 % of the total, under RCP8.5 the relative changes in temperature are larger, as are the changes in pH (140 %) and aragonite saturation state (170 %). The simulations reveal AOA is more effective under lower emissions, therefore the higher the emissions the more AOA is required to achieve the same reduction in global warming and ocean acidification. Finally, our simulated AOA for 2020–2100 in the RCP2.6 scenario is capable of offsetting warming and ameliorating ocean acidification increases at the global scale, but with highly variable regional responses

Benefits of federal community pastures on the prairies

Non-Peer ReviewedIn the wake of widespread soil erosion, during the 1930s, the federal governments passed the Prairie Farm Rehabilitation Administration (PFRA) act, establishing the agency, and through it a system of community pastures in the three prairie provinces. At present, PFRA operates 87 such pastures. The major motivation for this program was to reduce soil erosion through some careful land management practices, thereby enabling them to be a source of summer pasture for cattle grazing. This was seen as fostering greater economic security, stability and diversification in the region. Over time, many other uses of community pastures have emerged. Although grazing and breeding function has remained prominent, many other uses have become important enough so as not be totally ignored. Some of the notable uses include: wildlife and waterfowl habitats, recreational activity, preservation of biodiversity, preservation of fragile ecosystems, conservation of heritage sites, research activity, among others. In order to determine these uses, a survey of PFRA community pastures was undertaken during the summer of 2000. The results of this survey indicate that although grazing and breeding activities are still the major economic activities on these community pastures, the Canadian and the Prairie society benefits from these pastures in a significant manner. This study suggests that the PFRA community pastures are more than a place for farmers to leave their cattle for the summer period; they provide several benefits to local communities, and other members of the society through ecosystem functions, and other use and non-use related activities

Citizens who inject drugs: the 'Fitpack' study

Most injecting drug users have never been in drug treatment yet much research is done on samples with high treatment rates drawn from agency and peer recruited populations. This study accessed drug injectors with little or no prior drug treatment, described their characteristics, BBVI risk behaviours and feedback on services. Its results challenge some stereotypes about citizens who inject drugs. A sample of 511 'hidden' drug injectors, of whom only 28.7% had any specialist drug treatment agency contact, completed a questionnaire which was distributed with 'Fitpack' needle packs sold through community pharmacies in WA. The mean age of respondents was 26.2 years, 43.4% were women, 44.3% were living with their sexual partner, 41.7% were parents, and 46.4% were employed, mostly in full time work. In the previous month 61.2% had injected less frequently than daily. The study accessed a diverse group of drug injectors not typically seen in agency and peer recruited research. They provided useful feedback about how harm reduction strategies among injectors can be improved. However, they also reported higher rates of injecting and sharing than previously found in traditionally recruited samples of injectors which suggests there is no room for complacency regarding the potential for BBVI transmission in this grou

Evolution of oxygen utilization in multicellular organisms and implications for cell signalling in tissue engineering

Oxygen is one of the critically defining elements resulting in the existence of eukaryotic life on this planet. The rise and fall of this element can be tracked through time and corresponds with the evolution of diverse life forms, development of efficient energy production (oxidative phosphorylation) in single cell organisms, the evolution of multicellular organisms and the regulation of complex cell phenotypes. By understanding these events, we can plot the effect of oxygen on evolution and its direct influence on different forms of life today, from the whole organism to specific cells within multicellular organisms. In the emerging field of tissue engineering, understanding the role of different levels of oxygen for normal cell function as well as control of complex signalling cascades is paramount to effectively build 3D tissues in vitro and their subsequent survival when implanted

Overeducation across British regions

This paper analyses levels of over-education and wage returns to education for males across eleven regions of the UK using Labour Force Survey data. Significant differences are found in the probability of being over-educated across regions; also, differences are found in the return to the ‘correct’ level of education in each region, in each case associated with flexibility of movement between and into particular regions, which determines the ease of job matching. Furthermore, evidence is found that, after controlling for the level of education acquired, there exists a premium to the ‘correct’ level of education, which varies across UK regions

Publisher Correction: Enhanced clay formation key in sustaining the Middle Eocene Climatic Optimum (Nature Geoscience, (2023), 16, 8, (730-738), 10.1038/s41561-023-01234-y)

Correction to: Nature Geoscience, published online 31 July 2023. In the version of the article originally published, a reference was missing from the seventh paragraph of the “A global shift towards enhanced clay formation” section and the first paragraph of the “Further information on the successful model Scenario 8” section (in the latter instance, the reference is cited in the added text “although a global reorganisation of the silicon cycle may have also played a part”). The reference—Dunlea, A. G. et al. Cenozoic global cooling and increased seawater Mg/Ca via reduced reverse weathering. Nat. Commun. 8, 844 (2017)—has now been inserted as new ref. 54. In the “Data treatment and availability section”, the isotopic data, which can be found in the Figshare data repository at , were incorrectly said to be found in the PANGAEA data repository. These corrections have been made in the HTML and PDF versions of the article

The limits to global-warming mitigation by terrestrial carbon removal

Massive near‐term greenhouse gas emissions reduction is a precondition for staying “well below 2°C” global warming as envisaged by the Paris Agreement. Furthermore, extensive terrestrial carbon dioxide removal (tCDR) through managed biomass growth and subsequent carbon capture and storage is required to avoid temperature “overshoot” in most pertinent scenarios. Here, we address two major issues: First, we calculate the extent of tCDR required to “repair” delayed or insufficient emissions reduction policies unable to prevent global mean temperature rise of 2.5°C or even 4.5°C above pre‐industrial level. Our results show that those tCDR measures are unable to counteract “business‐as‐usual” emissions without eliminating virtually all natural ecosystems. Even if considerable (Representative Concentration Pathway 4.5 [RCP4.5]) emissions reductions are assumed, tCDR with 50% storage efficiency requires >1.1 Gha of the most productive agricultural areas or the elimination of >50% of natural forests. In addition, >100 MtN/yr fertilizers would be needed to remove the roughly 320 GtC foreseen in these scenarios. Such interventions would severely compromise food production and/or biosphere functioning. Second, we reanalyze the requirements for achieving the 160–190 GtC tCDR that would complement strong mitigation action (RCP2.6) in order to avoid 2°C overshoot anytime. We find that a combination of high irrigation water input and/or more efficient conversion to stored carbon is necessary. In the face of severe trade‐offs with society and the biosphere, we conclude that large‐scale tCDR is not a viable alternative to aggressive emissions reduction. However, we argue that tCDR might serve as a valuable “supporting actor” for strong mitigation if sustainable schemes are established immediately

New psychoactive substance use among regular psychostimulant users in Australia, 2010-2015

Objective: To examine the rates and patterns of new psychoactive substance (NPS) use amongst regular psychostimulant users (RPU) in Australia. Method: Data were obtained from the 2010-2015 Ecstasy and related Drugs Reporting System (EDRS), which comprised a total cross-sectional sample of 4122. RPU. Results: Recent use of 'any' NPS increased from 33% in 2010 to 40% in 2015, although trends of use differed significantly across NPS classes. The correlates associated with NPS use also varied across NPS classes: frequent (i.e. weekly or more) ecstasy users were more likely to report recent phenethylamine use; LSD users were more likely to report recent phenethylamine and tryptamine use; and daily cannabis users were more likely to report recent synthetic cannabinoid use than RPU who had not used NPS. 'Poly' NPS consumers were found to be a particularly high risk group and were significantly more likely to be younger, male, report daily cannabis use, report weekly or more ecstasy use, report recent LSD use, have higher levels of poly drug use, have overdosed on any drug in the past year, and to have engaged in past month criminal activity. Conclusion: NPS use has been established as a significant and ongoing practice amongst our sample of RPU. It appears that RPU seek out NPS with similar properties to the illicit drugs that they are already consuming, with poly NPS consumers found to be a particularly high risk group

Characterising dark net marketplace purchasers in a sample of regular psychostimulant users

Background: The past five years has seen a proliferation in marketplaces operating on the 'dark net' selling licit and illicit substances. While monitoring systems have investigated the specific substances for sale on these marketplaces, less is known about consumer motivations for accessing these marketplaces and factors associated with their use. Methods: An Australian national sample (n = 800) recruited on the basis of regular psychostimulant use was recruited and asked about purchasing substances from dark net marketplaces and the reasons for doing so. Respondents who had purchased any drug from a dark net marketplace in the preceding year were compared to those who had not in terms of demographic information and factors including drug use, criminal activity, and sexual and mental health. Results: Nine percent (n = 68) of the sample had purchased from dark net markets in the past year. MDMA, LSD and cannabis were the three most commonly purchased substances, and the main benefits cited for purchasing online were the better quality and lower cost of drugs available. Controlling for other factors, participants who purchased from dark net marketplaces in the past year tended to be younger, more likely to be involved in recent property crime and to have used more classes of drugs in the preceding six months, specifically psychedelics and 'new psychoactive drugs'. Conclusions: Though a small minority of participants reported having purchased drugs online in the preceding six months, these appeared to be a more