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This bi‐polar analysis resolves ice edge changes on space/time scales relevant for investigating seasonal ice‐ocean feedbacks and focuses on spatio‐temporal changes in the timing of annual sea ice retreat and advance over 1979/80 to 2010/11. Where Arctic sea ice decrease is fastest, the sea ice retreat is now nearly 2 months earlier and subsequent advance more than 1 month later (compared to 1979/80), resulting in a 3‐month longer summer ice‐free season. In the Antarctic Peninsula and Bellingshausen Sea region, sea ice retreat is more than 1 month earlier and advance 2 months later, resulting in a more than 3‐month longer summer ice‐free season. In contrast, in the western Ross Sea (Antarctica) region, sea ice retreat and advance are more than 1 month later and earlier respectively, resulting in a more than 2 month shorter summer ice‐free season. Regardless of trend magnitude or direction, and at latitudes mostly poleward of 70° (N/S), there is strong correspondence between anomalies in the timings of sea ice retreat and subsequent advance, but little correspondence between advance and subsequent retreat. These results support a strong ocean thermal feedback in autumn in response to changes in spring sea ice retreat. Further, model calculations suggest different net ocean heat changes in the Arctic versus Antarctic where autumn sea ice advance is 1 versus 2 months later. Ocean‐atmosphere changes, particularly in boreal spring and austral autumn (i.e., during ∼March‐May), are discussed and compared, as well as possible inter‐hemispheric climate connections. Key Points In some regions the ice‐free season has increased by >3 months over the last 32 years Anomalies in sea ice retreat & subsequent advance show strong correspondence Results support a positive atmospheric‐ocean‐ice feedback over summer but not winter

Reliable forecasts of climate change in the immediate future are difficult, especially on regional scales, where natural climate variations may amplify or mitigate anthropogenic warming in ways that numerical models capture poorly. By decomposing recent observed surface temperatures into components associated with ENSO, volcanic and solar activity, and anthropogenic influences, we anticipate global and regional changes in the next two decades. From 2009 to 2014, projected rises in anthropogenic influences and solar irradiance will increase global surface temperature 0.15 ± 0.03°C, at a rate 50% greater than predicted by IPCC. But as a result of declining solar activity in the subsequent five years, average temperature in 2019 is only 0.03 ± 0.01°C warmer than in 2014. This lack of overall warming is analogous to the period from 2002 to 2008 when decreasing solar irradiance also countered much of the anthropogenic warming. We further illustrate how a major volcanic eruption and a super ENSO would modify our global and regional temperature projections.

To clarify the grading of recommendations assessment, development and evaluation (GRADE) definition of certainty of evidence and suggest possible approaches to rating certainty of the evidence for systematic reviews, health technology assessments, and guidelines. This work was carried out by a project group within the GRADE Working Group, through brainstorming and iterative refinement of ideas, using input from workshops, presentations, and discussions at GRADE Working Group meetings to produce this document, which constitutes official GRADE guidance. Certainty of evidence is best considered as the certainty that a true effect lies on one side of a specified threshold or within a chosen range. We define possible approaches for choosing threshold or range. For guidelines, what we call a fully contextualized approach requires simultaneously considering all critical outcomes and their relative value. Less-contextualized approaches, more appropriate for systematic reviews and health technology assessments, include using specified ranges of magnitude of effect, for example, ranges of what we might consider no effect, trivial, small, moderate, or large effects. It is desirable for systematic review authors, guideline panelists, and health technology assessors to specify the threshold or ranges they are using when rating the certainty in evidence.

This document updates the American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/Latin American Thoracic Association guideline on idiopathic pulmonary fibrosis treatment. Systematic reviews and, when appropriate, meta-analyses were performed to summarize all available evidence pertinent to our questions. The evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach and then discussed by a multidisciplinary panel. Predetermined conflict-of-interest management strategies were applied, and recommendations were formulated, written, and graded exclusively by the nonconflicted panelists. After considering the confidence in effect estimates, the importance of outcomes studied, desirable and undesirable consequences of treatment, cost, feasibility, acceptability of the intervention, and implications to health equity, recommendations were made for or against specific treatment interventions. The panel formulated and provided the rationale for recommendations in favor of or against treatment interventions for idiopathic pulmonary fibrosis.

This article describes considerations for addressing intransitivity when assessing the certainty of the evidence from network meta-analysis (NMA) using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Intransitivity is induced by effect modification, that is, when the magnitude of the effect between an intervention and outcome differs depending on the level of another factor. To develop this GRADE concept paper, the lead authors conducted iterative discussions, computer simulations, and presentations to the GRADE project group and at GRADE working group meetings. The GRADE Working Group formally approved the article in July 2022. NMA authors can have a higher or a lower threshold to rate down the certainty of the evidence due to intransitivity, which depends on the extent of their concerns regarding the trustworthiness of indirect comparisons, and their view of the relative problems with rating down excessively or insufficiently. NMA authors should consider three main factors when addressing intransitivity: the credibility of effect modification, the strength of the effect modification, and the distribution of effect modifiers across the direct comparisons. To avoid double counting limitations of the evidence, authors should consider the relationship between intransitivity and other GRADE domains. NMA authors face theoretic and pragmatic challenges and in most situations need to assess intransitivity without the availability of empirical data. Thus, explicitness regarding perspective is crucial.

Global warming already influences precipitation, with more intense precipitation in many locations. Although the ‘wet-get-wetter, dry-get-drier’ tendency in mean precipitation holds in many locations, the situations for precipitation extremes are more complex, due to changes in dynamic and thermodynamic influences on atmospheric moisture distributions. Here, we build a dynamically interactive atmospheric moisture model for the present (2006–2025) and the future climate (2081–2100), using outputs from coupled ocean-atmosphere general circulation models. We find that the dynamic process of vertical advection of moisture dominates the same-day precipitation, while the smaller impact of the thermodynamic process provides available moisture for several days. As climate warms, we find that the dynamical-induced precipitation more completely exhausts the vertically-integrated moisture and the distribution of the dynamic process’s impact on precipitation exhibits a greater spread in the warmer future. The dynamical process is primarily responsible for more extreme heavy precipitation as climate warms, at all latitudes.

In the GRADE approach, the strength of a recommendation reflects the extent to which we can be confident that the composite desirable effects of a management strategy outweigh the composite undesirable effects. This article addresses GRADE's approach to determining the direction and strength of a recommendation. The GRADE describes the balance of desirable and undesirable outcomes of interest among alternative management strategies depending on four domains, namely estimates of effect for desirable and undesirable outcomes of interest, confidence in the estimates of effect, estimates of values and preferences, and resource use. Ultimately, guideline panels must use judgment in integrating these factors to make a strong or weak recommendation for or against an intervention.

Ample physical evidence shows that carbon dioxide (CO₂) is the single most important climate-relevant greenhouse gas in Earth's atmosphere. This is because CO₂, like ozone, N₂O, CH₄, and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapor can and does. Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect. Without the radiative forcing supplied by CO₂ and the other noncondensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state.

GRADE requires guideline developers to make an overall rating of confidence in estimates of effect (quality of evidence—high, moderate, low, or very low) for each important or critical outcome. GRADE suggests, for each outcome, the initial separate consideration of five domains of reasons for rating down the confidence in effect estimates, thereby allowing systematic review authors and guideline developers to arrive at an outcome-specific rating of confidence. Although this rating system represents discrete steps on an ordinal scale, it is helpful to view confidence in estimates as a continuum, and the final rating of confidence may differ from that suggested by separate consideration of each domain. An overall rating of confidence in estimates of effect is only relevant in settings when recommendations are being made. In general, it is based on the critical outcome that provides the lowest confidence.

An increasing number of organizations worldwide are using new and improved standards for developing trustworthy clinical guidelines. One of such approaches, developed by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) working group, offers systematic and transparent guidance in moving from evidence to recommendations. The GRADE strategy concentrates on four factors: the balance between benefits and harms, the certainty of the evidence, values and preferences, and resource considerations. However, it also considers issues around feasibility, equity, and acceptability of recommendations. GRADE distinguishes two types of recommendations: strong and weak. Strong recommendations reflect a clear preference for one alternative and should apply to all or almost all patients, obviating the need for a careful review of the evidence with each patient. Weak recommendations are appropriate when there is a close balance between desirable and undesirable consequences of alternative management strategies, uncertainty regarding the effects of the alternatives, uncertainty or variability in patients' values and preferences, or questionable cost-effectiveness. Weak recommendations usually require accessing the underlying evidence and a shared decision-making approach. Clinicians using GRADE recommendations should understand the meaning of the strength of the recommendation, be able to critically appraise the recommendation, and apply trustworthy recommendations according to their strength.