Sea-surface temperature pattern effects have slowed global warming and biased warming-based constraints on climate sensitivity.

The observed rate of global warming since the 1970s has been proposed as a strong constraint on equilibrium climate sensitivity (ECS) and transient climate response (TCR)-key metrics of the global climate response to greenhouse-gas forcing. Using CMIP5/6 models, we show that the inter-model relationship between warming and these climate sensitivity metrics (the basis for the constraint) arises from a similarity in transient and equilibrium warming patterns within the models, producing an effective climate sensitivity (EffCS) governing recent warming that is comparable to the value of ECS governing long-term warming under CO[Formula: see text] forcing. However, CMIP5/6 historical simulations do not reproduce observed warming patterns. When driven by observed patterns, even high ECS models produce low EffCS values consistent with the observed global warming rate. The inability of CMIP5/6 models to reproduce observed warming patterns thus results in a bias in the modeled relationship between recent global warming and climate sensitivity. Correcting for this bias means that observed warming is consistent with wide ranges of ECS and TCR extending to higher values than previously recognized. These findings are corroborated by energy balance model simulations and coupled model (CESM1-CAM5) simulations that better replicate observed patterns via tropospheric wind nudging or Antarctic meltwater fluxes. Because CMIP5/6 models fail to simulate observed warming patterns, proposed warming-based constraints on ECS, TCR, and projected global warming are biased low. The results reinforce recent findings that the unique pattern of observed warming has slowed global-mean warming over recent decades and that how the pattern will evolve in the future represents a major source of uncertainty in climate projections.

A new conceptual model of global ocean heat uptake.

We formulate a new conceptual model, named "MT2", to describe global ocean heat uptake, as simulated by atmosphere-ocean general circulation models (AOGCMs) forced by increasing atmospheric CO2, as a function of global-mean surface temperature change T and the strength of the Atlantic meridional overturning circulation (AMOC, M). MT2 has two routes whereby heat reaches the deep ocean. On the basis of circumstantial evidence, we hypothetically identify these routes as low- and high-latitude. In low latitudes, which dominate the global-mean energy balance, heat uptake is temperature-driven and described by the two-layer model, with global-mean T as the temperature change of the upper layer. In high latitudes, a proportion p (about 14%) of the forcing is taken up along isopycnals, mostly in the Southern Ocean, nearly like a passive tracer, and unrelated to T. Because the proportion p depends linearly on the AMOC strength in the unperturbed climate, we hypothesise that high-latitude heat uptake and the AMOC are both affected by some characteristic of the unperturbed global ocean state, possibly related to stratification. MT2 can explain several relationships among AOGCM projections, some found in this work, others previously reported: ∙ Ocean heat uptake efficiency correlates strongly with the AMOC. ∙ Global ocean heat uptake is not correlated with the AMOC. ∙ Transient climate response (TCR) is anticorrelated with the AMOC. ∙ T projected for the late twenty-first century under high-forcing scenarios correlates more strongly with the effective climate sensitivity than with the TCR.

Energy budget diagnosis of changing climate feedback.

The climate feedback determines how Earth's climate responds to anthropogenic forcing. It is thought to have been more negative in recent decades due to a sea surface temperature "pattern effect," whereby warming is concentrated in the western tropical Pacific, where nonlocal radiative feedbacks are very negative. This phenomenon has however primarily been studied within climate models. We diagnose a pattern effect from historical records as an evolution of the climate feedback over the past five decades. Our analysis assumes a constant rate of change of the climate feedback, which is justified post hoc. We find a decrease in climate feedback by 0.8 ± 0.5 W m-2 K-1 over the past 50 years, corresponding to a reduction in climate sensitivity. Earth system models' climate feedbacks instead increase over this period. Understanding and simulating this historical trend and its future evolution are critical for reliable climate projections.

Estimating Ocean Heat Uptake Using Boundary Green's Functions: A Perfect-Model Test of the Method.

Ocean heat uptake is caused by "excess heat" being added to the ocean surface by air-sea fluxes and then carried to depths by ocean transports. One way to estimate excess heat in the ocean is to propagate observed sea surface temperature (SST) anomalies downward using a Green's function (GF) representation of ocean transports. Taking a "perfect-model" approach, we test this GF method using a historical simulation, in which the true excess heat is diagnosed. We derive GFs from two approaches: (a) simulating GFs using idealized tracers, and (b) inferring GFs from simulated CFCs and climatological tracers. In the model world, we find that combining simulated GFs with SST anomalies reconstructs the Indo-Pacific excess heat with a root-mean-square error of 26% for depth-integrated changes; the corresponding number is 34% for inferred GFs. Simulated GFs are inaccurate because they are coarse grained in space and time to reduce computational cost. Inferred GFs are inaccurate because observations are insufficient constraints. Both kinds of GFs neglect the slowdown of the North Atlantic heat uptake as the ocean warms up. SST boundary conditions contain redistributive cooling in the Southern Ocean, which causes an underestimate of heat uptake there. All these errors are of comparable magnitude, and tend to compensate each other partially. Inferred excess heat is not sensitive to: (a) small changes in the shape of prior GFs, or (b) additional constraints from SF6 and bomb 14C.

Projected land ice contributions to twenty-first-century sea level rise.

The land ice contribution to global mean sea level rise has not yet been predicted1 using ice sheet and glacier models for the latest set of socio-economic scenarios, nor using coordinated exploration of uncertainties arising from the various computer models involved. Two recent international projects generated a large suite of projections using multiple models2-8, but primarily used previous-generation scenarios9 and climate models10, and could not fully explore known uncertainties. Here we estimate probability distributions for these projections under the new scenarios11,12 using statistical emulation of the ice sheet and glacier models. We find that limiting global warming to 1.5 degrees Celsius would halve the land ice contribution to twenty-first-century sea level rise, relative to current emissions pledges. The median decreases from 25 to 13 centimetres sea level equivalent (SLE) by 2100, with glaciers responsible for half the sea level contribution. The projected Antarctic contribution does not show a clear response to the emissions scenario, owing to uncertainties in the competing processes of increasing ice loss and snowfall accumulation in a warming climate. However, under risk-averse (pessimistic) assumptions, Antarctic ice loss could be five times higher, increasing the median land ice contribution to 42 centimetres SLE under current policies and pledges, with the 95th percentile projection exceeding half a metre even under 1.5 degrees Celsius warming. This would severely limit the possibility of mitigating future coastal flooding. Given this large range (between 13 centimetres SLE using the main projections under 1.5 degrees Celsius warming and 42 centimetres SLE using risk-averse projections under current pledges), adaptation planning for twenty-first-century sea level rise must account for a factor-of-three uncertainty in the land ice contribution until climate policies and the Antarctic response are further constrained.

Global reconstruction of historical ocean heat storage and transport.

Most of the excess energy stored in the climate system due to anthropogenic greenhouse gas emissions has been taken up by the oceans, leading to thermal expansion and sea-level rise. The oceans thus have an important role in the Earth's energy imbalance. Observational constraints on future anthropogenic warming critically depend on accurate estimates of past ocean heat content (OHC) change. We present a reconstruction of OHC since 1871, with global coverage of the full ocean depth. Our estimates combine timeseries of observed sea surface temperatures with much longer historical coverage than those in the ocean interior together with a representation (a Green's function) of time-independent ocean transport processes. For 1955-2017, our estimates are comparable with direct estimates made by infilling the available 3D time-dependent ocean temperature observations. We find that the global ocean absorbed heat during this period at a rate of 0.30 ± 0.06 W/[Formula: see text] in the upper 2,000 m and 0.028 ± 0.026 W/[Formula: see text] below 2,000 m, with large decadal fluctuations. The total OHC change since 1871 is estimated at 436 ± 91 [Formula: see text] J, with an increase during 1921-1946 (145 ± 62 [Formula: see text] J) that is as large as during 1990-2015. By comparing with direct estimates, we also infer that, during 1955-2017, up to one-half of the Atlantic Ocean warming and thermosteric sea-level rise at low latitudes to midlatitudes emerged due to heat convergence from changes in ocean transport.

Publisher Correction: Critical Southern Ocean climate model biases traced to atmospheric model cloud errors.

'In the original HTML version of this Article, ref.12 was incorrectly cited in the first sentence of the first paragraph of the Introduction. The correct citation is ref. 2. This has now been corrected in the HTML version of the Article; the PDF version was correct at the time of publication.'

Critical Southern Ocean climate model biases traced to atmospheric model cloud errors.

The Southern Ocean is a pivotal component of the global climate system yet it is poorly represented in climate models, with significant biases in upper-ocean temperatures, clouds and winds. Combining Atmospheric and Coupled Model Inter-comparison Project (AMIP5/CMIP5) simulations, with observations and equilibrium heat budget theory, we show that across the CMIP5 ensemble variations in sea surface temperature biases in the 40-60°S Southern Ocean are primarily caused by AMIP5 atmospheric model net surface flux bias variations, linked to cloud-related short-wave errors. Equilibration of the biases involves local coupled sea surface temperature bias feedbacks onto the surface heat flux components. In combination with wind feedbacks, these biases adversely modify upper-ocean thermal structure. Most AMIP5 atmospheric models that exhibit small net heat flux biases appear to achieve this through compensating errors. We demonstrate that targeted developments to cloud-related parameterisations provide a route to better represent the Southern Ocean in climate models and projections.

Relationship of tropospheric stability to climate sensitivity and Earth's observed radiation budget.

Climate feedbacks generally become smaller in magnitude over time under CO2 forcing in coupled climate models, leading to an increase in the effective climate sensitivity, the estimated global-mean surface warming in steady state for doubled CO2 Here, we show that the evolution of climate feedbacks in models is consistent with the effect of a change in tropospheric stability, as has recently been hypothesized, and the latter is itself driven by the evolution of the pattern of sea-surface temperature response. The change in climate feedback is mainly associated with a decrease in marine tropical low cloud (a more positive shortwave cloud feedback) and with a less negative lapse-rate feedback, as expected from a decrease in stability. Smaller changes in surface albedo and humidity feedbacks also contribute to the overall change in feedback, but are unexplained by stability. The spatial pattern of feedback changes closely matches the pattern of stability changes, with the largest increase in feedback occurring in the tropical East Pacific. Relationships qualitatively similar to those in the models among sea-surface temperature pattern, stability, and radiative budget are also found in observations on interannual time scales. Our results suggest that constraining the future evolution of sea-surface temperature patterns and tropospheric stability will be necessary for constraining climate sensitivity.

Integrating Smartphone Technology at the Time of Discharge from a Child and Adolescent Inpatient Psychiatry Unit.

OBJECTIVE: As smartphone technology becomes an increasingly important part of youth mental health, there has been little to no examination of how to effectively integrate smartphone-based safety planning with inpatient care. Our study sought to examine whether or not we could effectively integrate smartphone-based safety planning into the discharge process on a child and adolescent inpatient psychiatry unit. METHOD: Staff members completed a survey to determine the extent of smartphone ownership in a population of admitted child and adolescent inpatients. In addition to quantifying smartphone ownership, the survey also tracked whether youth would integrate their previously-established safety plan with a specific safety planning application on their smartphone (Be Safe) at the time of discharge. RESULTS: Sixty-six percent (50/76) of discharged youth owned a smartphone, which is consistent with prior reports of high smartphone ownership in adult psychiatric populations. A minority of youth (18%) downloaded the Be Safe app prior to discharge, with most (68%) suggesting they would download the app after discharge. Notably, all patients who downloaded the app prior to discharge were on their first admission to a psychiatric inpatient unit. CONCLUSION: Child and adolescent psychiatric inpatients have a clear interest in smartphone-based safety planning. Our results suggest that integrating smartphone-related interventions earlier in an admission might improve access before discharge. This highlights the tension between restricting and incorporating smartphone access for child and adolescent inpatients and may inform future study in this area.

OBJECTIF: Comme la technologie du téléphone intelligent devient une partie de plus en plus importante de la santé mentale des adolescents, il y a eu peu ou pas d'examen de la façon d'intégrer efficacement la planification de la sécurité liée au téléphone intelligent aux soins des patients hospitalisés. Notre étude cherchait à examiner si nous pouvions intégrer efficacement la planification de la sécurité liée au téléphone intelligent au processus du congé dans un service psychiatrique pour enfants et adolescents hospitalisés. MÉTHODE: Les membres du personnel ont répondu à un sondage pour déterminer combien de téléphones intelligents étaient la propriété d'une population d'enfants et d'adolescents hospitalisés. En plus de quantifier la propriété de téléphones intelligents, le sondage demandait aussi si les adolescents ajouteraient à leur plan de sécurité préétabli une application spécifique de planification de sécurité (Be Safe) dans leur téléphone intelligent au moment du congé. RÉSULTATS: Soixante-six pour cent (50/76) des adolescents ayant eu leur congé possédaient un téléphone intelligent, ce qui est conforme aux rapports précédents de propriété élevée de téléphones intelligents dans les populations psychiatriques adultes. Une minorité d'adolescents (18 %) ont téléchargé l'application Be Safe avant d'obtenir leur congé, et la plupart (68 %) ont suggéré qu'ils la téléchargeraient après le congé. À noter, tous les patients qui ont téléchargé l'application avant le congé étaient hospitalisés pour la première fois dans un service psychiatrique. CONCLUSION: Les enfants et les adolescents hospitalisés en psychiatrie ont un intérêt évident pour la planification de la sécurité liée au téléphone intelligent. Nos résultats suggèrent que l'intégration précoce des interventions liées au téléphone intelligent durant une hospitalisation peut améliorer l'accès avant le congé. Ceci met en évidence la tension entre la restriction et l'incorporation de l'accès au téléphone intelligent pour les enfants et les adolescents hospitalisés, et peut éclairer une future étude dans ce domaine.

Pharmacologic implications of inflammatory comorbidity in bipolar disorder.

Bipolar disorder (BD) is a chronic illness associated with significant morbidity and mortality. Epidemiological studies have established a strong association between BD and inflammatory comorbidities. Furthermore, illness course is more severe and treatment resistant in BD with comorbid inflammatory disease and vice versa. Immune dysfunction has therefore been proposed as a key pathophysiological nexus sub-serving the bidirectional interaction between BD and inflammatory comorbidities. The foregoing observations have provided the rational and impetus for repurposing anti-inflammatory agents for the treatment of BD. Clinical trials have shown promising results for a variety of mechanistically diverse anti-inflammatory agents. N-Acetylcysteine, infliximab, pioglitazone, celecoxib, aspirin, and omega-3 polyunsaturated fatty acids have shown an antidepressant effect in BD when administered adjunctively to conventional treatments. Currently, insufficient evidence exists to support the routine use of anti-inflammatory agents in the treatment of BD with inflammatory comorbidities; however, several more clinical trials are current underway which may guide clinical application in the near future. Anti-inflammatory agents will likely be most useful for the subpopulation of BD where immune dysfunction is a driving pathogenic factor, such as in patients with inflammatory comorbidities. Future studies are striving to stratify subjects based on immune function or dysfunction in order to better understand which subset of BD subjects will benefit most from anti-inflammatory therapies.

Deconstructing Diabetes and Depression: Clinical Context, Treatment Strategies, and New Directions.

Depression and diabetes are common, chronic, and frequently comorbid diseases that contribute substantially to global disability and mortality. Their relationship is bidirectional: depression increases the risk of developing type 2 diabetes mellitus (T2DM), and diabetes increases the risk of depression. Unhealthy lifestyles and poor self-care by patients with depression contribute to the increased T2DM risk. The psychosocial burden of a diabetes diagnosis and its eventual complications predispose diabetic patients to depressive symptoms. Neuroendocrine alterations and inflammation may underlie the increased risk of T2DM in depression but are also proposed as common causative factors for both illnesses. Screening for depression is essential in T2DM, and vice versa. Selective serotonin reuptake inhibitors effectively treat depression of patients with diabetes and positively influence glycemic control. Psychological interventions are effective for depressive symptoms, but their effect on glycemic control varies. Novel depression interventions targeting inflammation or insulin resistance underscore the common biological underpinnings of mood and metabolism.

A large ozone-circulation feedback and its implications for global warming assessments.

State-of-the-art climate models now include more climate processes which are simulated at higher spatial resolution than ever1. Nevertheless, some processes, such as atmospheric chemical feedbacks, are still computationally expensive and are often ignored in climate simulations1,2. Here we present evidence that how stratospheric ozone is represented in climate models can have a first order impact on estimates of effective climate sensitivity. Using a comprehensive atmosphere-ocean chemistry-climate model, we find an increase in global mean surface warming of around 1°C (~20%) after 75 years when ozone is prescribed at pre-industrial levels compared with when it is allowed to evolve self-consistently in response to an abrupt 4×CO2 forcing. The difference is primarily attributed to changes in longwave radiative feedbacks associated with circulation-driven decreases in tropical lower stratospheric ozone and related stratospheric water vapour and cirrus cloud changes. This has important implications for global model intercomparison studies1,2 in which participating models often use simplified treatments of atmospheric composition changes that are neither consistent with the specified greenhouse gas forcing scenario nor with the associated atmospheric circulation feedbacks3-5.

Penetration of human-induced warming into the world's oceans.

A warming signal has penetrated into the world's oceans over the past 40 years. The signal is complex, with a vertical structure that varies widely by ocean; it cannot be explained by natural internal climate variability or solar and volcanic forcing, but is well simulated by two anthropogenically forced climate models. We conclude that it is of human origin, a conclusion robust to observational sampling and model differences. Changes in advection combine with surface forcing to give the overall warming pattern. The implications of this study suggest that society needs to seriously consider model predictions of future climate change.

Climatology: threatened loss of the Greenland ice-sheet.

The Greenland ice-sheet would melt faster in a warmer climate and is likely to be eliminated--except for residual glaciers in the mountains--if the annual average temperature in Greenland increases by more than about 3 degrees C. This could raise the global average sea-level by 7 metres over a period of 1,000 years or more. We show here that concentrations of greenhouse gases will probably have reached levels before the year 2100 that are sufficient to raise the temperature past this warming threshold.