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Ozone is an important atmospheric constituent due to its role as both a greenhouse gas and an oxidant. Recent measurements in the Mount Everest region indicate the presence of ozone at elevations from 5000 to 9000 ma.s.l. that are the result of both stratospheric and tropospheric sources. Here we examine the temporal variability in the surface ozone concentration measurements from the ABC-Pyramid Observatory in the Mount Everest region during 2006 and compare it to the total column ozone data from the OMI instrument as well as meteorological fields from the ECMWF Interim Reanalysis. Both the surface ozone at and the total column ozone over the ABC-Pyramid Observatory site have maxima in the pre-monsoon period. We show that during this period, there is a statistically significant correlation between the two suggesting that the stratosphere was an important contributor to the high levels of ozone observed during the period. There was a hiatus in the monsoon in June that resulted in a return of westerlies over northern Indian and southern Tibet and as a result, the aforementioned correlation extended into June. No such correlation exists during the monsoon and post-monsoon periods. Spatial correlation maps between the surface ozone and total column ozone as well as meteorological fields from the ECMWF Interim Reanalysis support the contention that there is a significant stratospheric contribution in the pre-monsoon period that is absent during and after the monsoon. [ABSTRACT FROM AUTHOR]

Atmospheric methane removal (e.g. in situ methane oxidation to carbon dioxide) may be needed to offset continued methane release and limit the global warming contribution of this potent greenhouse gas. Because mitigating most anthropogenic emissions of methane is uncertain this century, and sudden methane releases from the Arctic or elsewhere cannot be excluded, technologies for methane removal or oxidation may be required. Carbon dioxide removal has an increasingly well-established research agenda and technological foundation. No similar framework exists for methane removal. We believe that a research agenda for negative methane emissions-'removal' or atmospheric methane oxidation-is needed. We outline some considerations for such an agenda here, including a proposed Methane Removal Model Intercomparison Project (MR-MIP). This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 1)'.

Mitigating climate change requires a diverse portfolio of technologies and approaches, including negative emissions or removal of greenhouse gases. Previous literature focuses primarily on carbon dioxide removal, but methane removal may be an important complement to future efforts. Methane removal has at least two key benefits: reducing temperature more rapidly than carbon dioxide removal and improving air quality by reducing surface ozone concentration. While some removal technologies are being developed, modelling of their impacts is limited. Here, we conduct the first simulations using a methane emissions-driven Earth System Model to quantify the climate and air quality co-benefits of methane removal, including different rates and timings of removal. We define a novel metric, the effective cumulative removal, and use it to show that each effective petagram of methane removed causes a mean global surface temperature reduction of 0.21 ± 0.04°C and a mean global surface ozone reduction of 1.0 ± 0.2 parts per billion. Our results demonstrate the effectiveness of methane removal in delaying warming thresholds and reducing peak temperatures, and also allow for direct comparisons between the impacts of methane and carbon dioxide removal that could guide future research and climate policy. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 1)'.

Accurate and early identification of women at risk from alcohol consumption during pregnancy allows education and support programmes to be targeted at those most in need. We aimed to conduct a systematic review to compare the efficacy of blood analysis and maternal self-report in detecting at risk women during pregnancy. This review investigated diagnostic accuracy. We searched four databases (Medline, Embase, Psychinfo and CINAHL) for relevant articles and conducted hand searches of recent issues of key journals in the field. No restriction was placed on inclusion in terms of publication date or language. Studies were deemed eligible if they were original research and included a direct comparison of the results of blood biomarker analysis and self-reported alcohol use for the detection of alcohol consumption in pregnant women. Quality appraisal of included studies was conducted using the QUADAS II tool. Eight studies met the inclusion criteria. Gamma-glutamyltransferase (GGT) was investigated in five studies, mean corpuscular volume (MCV) and phosphatidylethanol (PEth) in three studies and carbohydrate deficient transferrin (CDT), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and whole blood associated acetaldehyde assay (WBAA) were each investigated in two studies. Although all of the studies were rated of good methodological quality, none of the biomarkers had both high sensitivity and specificity when compared to self-report. There was some evidence that a combination of biomarkers, or combining biomarkers with self-report, increases accuracy. In summary, the blood biomarkers examined were of limited use in screening for low and moderate alcohol consumption in pregnancy when compared to self-report. However, certain biomarkers, such and CDT and PEth may complement self-report and help improve the accuracy of diagnosis., (Copyright © 2017 Elsevier B.V. All rights reserved.)