GISS-E2.1: Configurations and Climatology.

This paper describes the GISS-E2.1 contribution to the Coupled Model Intercomparison Project, Phase 6 (CMIP6). This model version differs from the predecessor model (GISS-E2) chiefly due to parameterization improvements to the atmospheric and ocean model components, while keeping atmospheric resolution the same. Model skill when compared to modern era climatologies is significantly higher than in previous versions. Additionally, updates in forcings have a material impact on the results. In particular, there have been specific improvements in representations of modes of variability (such as the Madden-Julian Oscillation and other modes in the Pacific) and significant improvements in the simulation of the climate of the Southern Oceans, including sea ice. The effective climate sensitivity to 2 × CO2 is slightly higher than previously at 2.7-3.1°C (depending on version) and is a result of lower CO2 radiative forcing and stronger positive feedbacks.

Pandemic March: 2019 Coronavirus Disease's First Wave Circumnavigates the Globe.

OBJECTIVE: March 2020 was a pivotal month for the worldwide geographic and numeric expansion of the first wave of Coronavirus Disease 2019 (COVID-19). We examined the major storylines that depicted this explosive spread of COVID-19 around the globe. METHODS: A detailed review of World Health Organization (WHO) situation reports, surveillance summaries, and online resources allowed us to quantify the increases in cases and deaths by region and by country throughout the month of March 2020. RESULTS: During March, COVID-19 was officially declared by the WHO to be a pandemic. COVID-19 emerged from a focalized outbreak in the Western Pacific Region and rapidly proliferated across all continents worldwide. Globally, cumulative numbers of confirmed cases increased by a factor of nine throughout the month. During the entire month, cases rose exponentially throughout Europe. Starting in mid-March, confirmed cases accelerated coast-to-coast throughout the United States and, on March 26, the United States surpassed all other nations to rank first in numbers of cases. COVID-19 mortality lagged several weeks behind but by month's end, death tolls were also rising exponentially. CONCLUSION: March 2020 was a consequential month when the COVID-19 pandemic wrapped completely around the planet, with outbreaks erupting in most nations worldwide.

The tropical rain belts with an annual cycle and a continent model intercomparison project: TRACMIP.

This paper introduces the Tropical Rain belts with an Annual cycle and a Continent Model Inter-comparison Project (TRACMIP). TRACMIP studies the dynamics of tropical rain belts and their response to past and future radiative forcings through simulations with 13 comprehensive and one simplified atmosphere models coupled to a slab ocean and driven by seasonally varying insolation. Five idealized experiments, two with an aquaplanet setup and three with a setup with an idealized tropical continent, fill the space between prescribed-SST aquaplanet simulations and realistic simulations provided by CMIP5/6. The simulations reproduce key features of present-day climate and expected future climate change, including an annual-mean intertropical convergence zone (ITCZ) that is located north of the equator and Hadley cells and eddy-driven jets that are similar to present-day climate. Quadrupling CO2 leads to a northward ITCZ shift and preferential warming in Northern high latitudes. The simulations show interesting CO2-induced changes in the seasonal excursion of the ITCZ and indicate a possible state dependence of climate sensitivity. The inclusion of an idealized continent modulates both the control climate and the response to increased CO2; for example, it reduces the northward ITCZ shift associated with warming and, in some models, climate sensitivity. In response to eccentricity-driven seasonal insolation changes, seasonal changes in oceanic rainfall are best characterized as a meridional dipole, while seasonal continental rainfall changes tend to be symmetric about the equator. This survey illustrates TRACMIP's potential to engender a deeper understanding of global and regional climate and to address questions on past and future climate change.

Climate sensitivity, sea level and atmospheric carbon dioxide.

Cenozoic temperature, sea level and CO2 covariations provide insights into climate sensitivity to external forcings and sea-level sensitivity to climate change. Climate sensitivity depends on the initial climate state, but potentially can be accurately inferred from precise palaeoclimate data. Pleistocene climate oscillations yield a fast-feedback climate sensitivity of 3±1(°)C for a 4 W m(-2) CO2 forcing if Holocene warming relative to the Last Glacial Maximum (LGM) is used as calibration, but the error (uncertainty) is substantial and partly subjective because of poorly defined LGM global temperature and possible human influences in the Holocene. Glacial-to-interglacial climate change leading to the prior (Eemian) interglacial is less ambiguous and implies a sensitivity in the upper part of the above range, i.e. 3-4(°)C for a 4 W m(-2) CO2 forcing. Slow feedbacks, especially change of ice sheet size and atmospheric CO2, amplify the total Earth system sensitivity by an amount that depends on the time scale considered. Ice sheet response time is poorly defined, but we show that the slow response and hysteresis in prevailing ice sheet models are exaggerated. We use a global model, simplified to essential processes, to investigate state dependence of climate sensitivity, finding an increased sensitivity towards warmer climates, as low cloud cover is diminished and increased water vapour elevates the tropopause. Burning all fossil fuels, we conclude, would make most of the planet uninhabitable by humans, thus calling into question strategies that emphasize adaptation to climate change.

Role of thiopurine metabolite testing and thiopurine methyltransferase determination in pediatric IBD.

Thiopurines have been used in inflammatory bowel disease (IBD) for >30 years, and measurements of both thiopurine methyltransferase (TPMT) and thiopurine (TP) metabolites, 6-thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine (6-MMP), have been readily available. The North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) Committee on Inflammatory Bowel Disease thought it appropriate to review the present indications for use of TPMT and TP metabolite testing. Substantial evidence demonstrates that TP therapy is useful for both Crohn disease and ulcerative colitis. Review of the existing data yielded the following recommendations. TPMT testing is recommended before initiation of TPs to identify individuals who are homozygote recessive or have extremely low TPMT activity, with the latter having more reliability than the former. Individuals who are homozygous recessive or have extremely low TPMT activity should avoid the use of TPs because of concerns for significant leukopenia. TMPT testing does not predict all cases of leukopenia and has no value to predict hypersensitivity adverse effects such as pancreatitis. Any potential value to reduce the risk of malignancy has not been studied. All individuals taking TPs should have routine monitoring with complete blood cell count and white blood cell count differential to evaluate for leukopenia regardless of TPMT testing results. Metabolite testing can be used to determine adherence with TP therapy. Metabolite testing can be used to guide dose increases or modifications in patients with active disease. Consideration would include either increasing the dose, changing therapy or for those with elevated transaminases or an elevated 6-MMP, using adjunctive allopurinol to help raise 6-thioguanine metabolites and suppress formation of 6-MMP. Routine and repetitive metabolite testing has little or no role in patients who are doing well and taking an acceptable dose of a TP.

Neutrophilic infiltration in gluten-sensitive enteropathy is neither uncommon nor insignificant: assessment of duodenal biopsies from 267 pediatric and adult patients.

The histologic findings of celiac disease, that is, gluten-sensitive enteropathy (GSE), are dominated by increased intraepithelial lymphocytes, villous blunting, lymphoplasmacytic infiltration of lamina propria, and crypt hyperplasia. To date, neutrophils have not been thought to constitute a significant cell type in GSE, and their presence often invokes consideration of alternative diagnoses. Thus, we sought to determine the prevalence and severity of neutrophilic infiltration in duodenal biopsies from patients with GSE. The degree of neutrophilic infiltration and features characteristic of GSE were assessed in duodenal biopsies from 267 clinically confirmed GSE patients (116 adults and 151 children). These specimens were graded by the disease activity score (DAS) and the neutrophilic activity score (NAS). Gastric antral biopsies obtained from 195 patients were also evaluated for lymphocytic gastritis. NAS was correlated with DAS and other clinicopathologic features. We found that 56% of pediatric and 28% of adult GSE patients had significant duodenal neutrophilia. NAS was higher in children than in adults (2.3 vs. 1.2, P<0.001). Multivariate regression showed that DAS, eosinophilic infiltration, and foveolar metaplasia correlated positively, and age correlated negatively with NAS. Lymphocytic gastritis was seen in 21.5% of the gastric biopsies. The presence of lymphocytic gastritis correlated positively with NAS and DAS, and in the pediatric population it correlated negatively with age. Significant duodenal neutrophilia is often found in patients with celiac disease, especially in the pediatric population, and is associated with more active disease. Thus, the findings of duodenal neutrophilia in biopsies, otherwise consistent with GSE, should not preclude the diagnosis of GSE.

Analysis of current treatments used in clinical practice in a pediatric summer camp population for children with inflammatory bowel disease.

BACKGROUND: Many treatment options exist for children with inflammatory bowel disease (IBD), yet the lack of clinical guidelines for management has lead to great variation in care. The purpose of this project was to evaluate current treatment modalities in children from the Northeast US who applied to the 2010 session of Camp Oasis, a Crohn's and Colitis Foundation of America (CCFA)-sponsored camp for children ages 8-17 with medically stable IBD. METHODS: Patient demographics, medical history, and current medications were entered into the camp database. The subjects were divided into two groups; Crohn's disease (CD) or ulcerative colitis/indeterminate colitis (UC/IC). In all, 164 applicants were included, 121 (74%) with CD and 43 (26%) with UC/IC. RESULTS: There were no significant differences between the two groups with respect to median age at the time of camp, median age at diagnosis, or median length of illness. Of the 121 applicants with CD, 13 (10.7%) were on an antibiotic, 56 (46.3%) were on a 5-aminosalicylate (5-ASA), 10 (8.3%) were on corticosteroids, 57 (47.1%) were on immunomodulators, and 44 (36.4%) were on a biologic agent. Six (5%) were on both an immunomodulator and a biologic agent. Of the 43 subjects with UC/IC, 27 (62.7%) were on a 5-ASA, two (4.7%) were on corticosteroids, 13 (30.2%) were on an immunomodulator, and four (9.3%) were on a biologic agent. The groups were similar with regard to surgery (20.7% for CD and 18.6% for UC/IC). CONCLUSIONS: Identifying current treatment patterns may serve to highlight variations in care among this pediatric IBD population.

Dynamic skin tension in the forearm: effects of pronation and supination.

PURPOSE: Longitudinal scars on the radial quadrant of the distal forearm skin envelope are typically observed to be wider than those on the ulnar quadrant and have an increased incidence of hypertrophic change. Forearm rotation movements may produce differential skin tensions within the forearm skin envelope, and this may lead to differential scarring patterns. This study was designed to measure skin tension changes in the forearm as a result of rotational position to see if these would be consistent with the hypothesis that greater tension changes are observed on the radial aspect of the forearm. METHODS: The effect of forearm position on the magnitude and direction of skin tension was measured on human volunteers. Standardized circles were marked in circumferential fashion at specified intervals on forearm skin, and the angular and dimensional distortion of these circles that occurred with forearm rotation was measured with caliper and goniometer. Data were analyzed for statistical significance using paired t-test. RESULTS: Pronation and supination resulted in marked angular rotation of the lines of maximal skin tension at all sites on the forearm. Supination resulted in a greater angular deviation of the lines of maximal skin tension from the longitudinal line of usual surgical incision, particularly on the radial aspect of the forearm. In supination, the magnitude of ellipsoid deformation at the distal forearm was greater on the radial aspect compared with that of the ulnar. Similar significant changes were also demonstrated at the mid-forearm and proximal forearm levels. CONCLUSIONS: This study systematically maps the effects of pronation and supination on skin tension within the forearm skin envelope. The significant changes occurring in both the ellipsoid deformation and ellipsoid orientation support our hypothesis that the magnitude of skin tension changes significantly with forearm rotation. The radial aspect of the distal forearm experiences the greatest changes, particularly as the forearm supinates.

Climate change and trace gases.

Palaeoclimate data show that the Earth's climate is remarkably sensitive to global forcings. Positive feedbacks predominate. This allows the entire planet to be whipsawed between climate states. One feedback, the 'albedo flip' property of ice/water, provides a powerful trigger mechanism. A climate forcing that 'flips' the albedo of a sufficient portion of an ice sheet can spark a cataclysm. Inertia of ice sheet and ocean provides only moderate delay to ice sheet disintegration and a burst of added global warming. Recent greenhouse gas (GHG) emissions place the Earth perilously close to dramatic climate change that could run out of our control, with great dangers for humans and other creatures. Carbon dioxide (CO2) is the largest human-made climate forcing, but other trace constituents are also important. Only intense simultaneous efforts to slow CO2 emissions and reduce non-CO2 forcings can keep climate within or near the range of the past million years. The most important of the non-CO2 forcings is methane (CH4), as it causes the second largest human-made GHG climate forcing and is the principal cause of increased tropospheric ozone (O3), which is the third largest GHG forcing. Nitrous oxide (N2O) should also be a focus of climate mitigation efforts. Black carbon ('black soot') has a high global warming potential (approx. 2000, 500 and 200 for 20, 100 and 500 years, respectively) and deserves greater attention. Some forcings are especially effective at high latitudes, so concerted efforts to reduce their emissions could preserve Arctic ice, while also having major benefits for human health, agricultural productivity and the global environment.

Earth's energy imbalance: confirmation and implications.

Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols, among other forcings, calculates that Earth is now absorbing 0.85 +/- 0.15 watts per square meter more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years. Implications include (i) the expectation of additional global warming of about 0.6 degrees C without further change of atmospheric composition; (ii) the confirmation of the climate system's lag in responding to forcings, implying the need for anticipatory actions to avoid any specified level of climate change; and (iii) the likelihood of acceleration of ice sheet disintegration and sea level rise.