The global methane budget 2000–2017

Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions and concentrations of CH4 continue to increase, making CH4 the second most important human-influenced greenhouse gas in terms of climate forcing, after carbon dioxide (CO2). The relative importance of CH4 compared to CO2 depends on its shorter atmospheric lifetime, stronger warming potential, and variations in atmospheric growth rate over the past decade, the causes of which are still debated. Two major challenges in reducing uncertainties in the atmospheric growth rate arise from the variety of geographically overlapping CH4 sources and from the destruction of CH4 by short-lived hydroxyl radicals (OH). To address these challenges, we have established a consortium of multidisciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate new research aimed at improving and regularly updating the global methane budget. Following Saunois et al. (2016), we present here the second version of the living review paper dedicated to the decadal methane budget, integrating results of top-down studies (atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up estimates (including process-based models for estimating land surface emissions and atmospheric chemistry, inventories of anthropogenic emissions, and data-driven extrapolations). For the 2008–2017 decade, global methane emissions are estimated by atmospheric inversions (a top-down approach) to be 576 Tg CH4 yr−1 (range 550–594, corresponding to the minimum and maximum estimates of the model ensemble). Of this total, 359 Tg CH4 yr−1 or ∼ 60 % is attributed to anthropogenic sources, that is emissions caused by direct human activity (i.e. anthropogenic emissions; range 336–376 Tg CH4 yr−1 or 50 %–65 %). The mean annual total emission for the new decade (2008–2017) is 29 Tg CH4 yr−1 larger than our estimate for the previous decade (2000–2009), and 24 Tg CH4 yr−1 larger than the one reported in the previous budget for 2003–2012 (Saunois et al., 2016). Since 2012, global CH4 emissions have been tracking the warmest scenarios assessed by the Intergovernmental Panel on Climate Change. Bottom-up methods suggest almost 30 % larger global emissions (737 Tg CH4 yr−1, range 594–881) than top-down inversion methods. Indeed, bottom-up estimates for natural sources such as natural wetlands, other inland water systems, and geological sources are higher than top-down estimates. The atmospheric constraints on the top-down budget suggest that at least some of these bottom-up emissions are overestimated. The latitudinal distribution of atmospheric observation-based emissions indicates a predominance of tropical emissions (∼ 65 % of the global budget, < 30∘ N) compared to mid-latitudes (∼ 30 %, 30–60∘ N) and high northern latitudes (∼ 4 %, 60–90∘ N). The most important source of uncertainty in the methane budget is attributable to natural emissions, especially those from wetlands and other inland waters. Some of our global source estimates are smaller than those in previously published budgets (Saunois et al., 2016; Kirschke et al., 2013). In particular wetland emissions are about 35 Tg CH4 yr−1 lower due to improved partition wetlands and other inland waters. Emissions from geological sources and wild animals are also found to be smaller by 7 Tg CH4 yr−1 by 8 Tg CH4 yr−1, respectively. However, the overall discrepancy between bottom-up and top-down estimates has been reduced by only 5 % compared to Saunois et al. (2016), due to a higher estimate of emissions from inland waters, highlighting the need for more detailed research on emissions factors. Priorities for improving the methane budget include (i) a global, high-resolution map of water-saturated soils and inundated areas emitting methane based on a robust classification of different types of emitting habitats; (ii) further development of process-based models for inland-water emissions; (iii) intensification of methane observations at local scales (e.g., FLUXNET-CH4 measurements) and urban-scale monitoring to constrain bottom-up land surface models, and at regional scales (surface networks and satellites) to constrain atmospheric inversions; (iv) improvements of transport models and the representation of photochemical sinks in top-down inversions; and (v) development of a 3D variational inversion system using isotopic and/or co-emitted species such as ethane to improve source partitioning

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Treatment of traumatic thoracolumbar spine fractures:A multicenter prospective randomized study of operative versus nonsurgical treatment

Study Design. Multicenter prospective randomized trial. Objective. To test the hypotheses that thoracolumbar AO Type A spine fractures without neurologic deficit, managed with short-segment posterior stabilization will show an improved radiographic outcome and at least the same functional outcome as compared with nonsurgically treated thoracolumbar fractures. Summary of Background Data. There are various opinions regarding the ideal management of thoracolumbar Type A spine fractures without neurologic deficit. Both operative and nonsurgical approaches are advocated. Methods. Patients were randomized for operative or nonsurgical treatment. Data sampling involved demographics, fracture classifications, radiographic evaluation, and functional outcome. Results. Sixteen patients received nonsurgical therapy, and 18 received surgical treatment. Follow-up was completed for 32 (94%) of the patients after a mean of 4.3 years. At the end of follow-up, both local and regional kyphotic deformity was significantly less in the operatively treated group. All functional outcome scores (VAS Pain, VAS Spine Score, and RMDQ-24) showed significantly better results in the operative group. The percentage of patients returning to their original jobs was found to be significantly higher in the operative treated group. Conclusions. Patients with a Type A3 thoracolumbar spine fracture without neurologic deficit should be treated by short-segment posterior stabilization

Weight-bearing and mobilization in the postoperative care of ankle fractures : A systematic review and meta-analysis of randomized controlled trials and cohort studies

Purpose: To determine the effectiveness and safety of interventions used for rehabilitation after open reduction and internal fixation of ankle fractures. Methods: A systematic review and meta-analysis was performed using both randomized trials and cohort studies. The effect of mobilization, weight-bearing, and unprotected weight-bearing as tolerated on postoperative recovery was compared using the Olerud Molander score, return to work/daily activities, and the rate of complications. Results: A total of 25 articles were included. Ankle exercises resulted in earlier return to work and/or daily activities compared to immobilization (mean difference (MD) -20.76 days; 95% confidence interval (CI) -40.02 to -1.50). There was no difference in the rate of complications between exercises and immobilization (risk ratio (RR) 1.22; 95% CI 0.60 to 2.45) or between early and late weight-bearing (RR 1.26; 95%CI 0.56 to 2.85). Interpretation: Results of this meta-analysis show that following ankle surgery, 1) active exercises accelerate return to work and daily activities compared to immobilization, 2) early weight-bearing tends to accelerate return to work and daily activities compared to late weight-bearing. Active exercises in combination with immediate weight-bearing may be a safe option

Effects of <i>Spartina</i> invasion on soil organic carbon, microbial biomass carbon and nitrogen in different coastal wetlands.

<p>Effects of <i>Spartina</i> invasion on soil organic carbon, microbial biomass carbon and nitrogen in different coastal wetlands.</p

Accuracy of Prehospital Triage in Selecting Severely Injured Trauma Patients

A major component of trauma care is adequate prehospital triage. To optimize the prehospital triage system, it is essential to gain insight in the quality of prehospital triage of the entire trauma system. To prospectively evaluate the quality of the field triage system to identify severely injured adult trauma patients. Prehospital and hospital data of all adult trauma patients during 2012 to 2014 transported with the highest priority by emergency medical services professionals to 10 hospitals in Central Netherlands were prospectively collected. Prehospital data collected by the emergency medical services professionals were matched to hospital data collected in the trauma registry. An Injury Severity Score of 16 or more was used to determine severe injury. The quality and diagnostic accuracy of the field triage protocol and compliance of emergency medical services professionals to the protocol. A total of 4950 trauma patients were evaluated of which 436 (8.8%) patients were severely injured. The undertriage rate based on actual destination facility was 21.6% (95% CI, 18.0-25.7) with an overtriage rate of 30.6% (95% CI, 29.3-32.0). Analysis of the protocol itself, regardless of destination facility, resulted in an undertriage of 63.8% (95% CI, 59.2-68.1) and overtriage of 7.4% (95% CI, 6.7-8.2). The compliance to the field triage trauma protocol was 73% for patients with a level 1 indication. More than 20% of the patients with severe injuries were not transported to a level I trauma center. These patients are at risk for preventable morbidity and mortality. This finding indicates the need for improvement of the prehospital triage protoco

Effect of weight-bearing; return to work/daily activities.

<p>The mean difference (SD) on the return to work/daily activites is shown between the early weight-bearing groups and the late weight-bearing groups.</p

Process from initial search to final inclusion of studies on postoperative care of ankle fractures.

<p>A flowchart following the PRISMA guidelines of the search strategy.</p