Cloud Cover Feedback Moderates Fennoscandian Summer Temperature Changes Over the Past 1,000 Years

Northern Fennoscandia has experienced little summer warming over recent decades, in 24 contrast to the hemispheric trend, which is strongly linked to greenhouse gas emissions. A likely25 explanation is the feedback between cloud cover and temperature. We establish the long- and26 short-term relationship between summer cloud cover and temperature over Northern27 Fennoscandia, by analysing meteorological and proxy climate data. We identify opposing28 feedbacks operating at different timescales. At short timescales, dominated by internal29 variability, the cloud cover-temperature feedback is negative; summers with increased cloud30 cover are cooler and sunny summers are warmer. However, over longer timescales, at which31 forced climate changes operate, this feedback is positive, rising temperatures causing increased32 regional cloud cover and vice versa. This has occurred both during warm (Medieval Climate33 Anomaly and at present) and cool (Little Ice Age) periods. This two-way feedback relationship34 therefore moderates Northern Fennoscandian temperatures during both warm and cool35 hemispheric periods

Maritime transport and regional climate change impacts in large EU islands and archipelagos

Maritime transport is a vital sector for global trade and the world economy. Particularly for islands, there is also an important social dimension of this sector, since island communities strongly rely on it for a connection with the mainland and the transportation of goods and passengers. Furthermore, islands are exceptionally vulnerable to climate change, as the rising sea level and extreme events are expected to induce severe impacts. Such hazards are anticipated to also affect the operations of the maritime transport sector by affecting either the port infrastructure or ships en route. The present study is an effort to better comprehend and assess the future risk of maritime transport disruption in six European islands and archipelagos, and it aims at supporting regional to local policy and decision-making. We employ state-of-the-art regional climate datasets and the widely used impact chain approach to identify the different components that might drive such risks. Larger islands (e.g., Corsica, Cyprus and Crete) are found to be more resilient to the impacts of climate change on maritime operations. Our findings also highlight the importance of adopting a low-emission pathway, since this will keep the risk of maritime transport disruption similar to present levels or even slightly decreased for some islands because of an enhanced adaptation capacity and advantageous demographic changes.Open Access funding enabled and organized by Projekt DEAL.This work has received funding from the European Union’s H2020 Research and Innovation Programme under grant agreement no. 776661 (SOCLIMPACT project). It was also supported by the EMME-CARE project, which has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement no. 856612, as well as matching co-funding by the Government of the Republic of Cyprus.Peer reviewe

The climate sensitivity of Norway spruce [Picea abies (L.) Karst.] in the southeastern European Alps

Tree ring chronologies were developed from trees growing at two sites in Slovenia which differed in their ecological and climatological characteristics. Ring width, maximum latewood density, annual height increment and latewood cellulose carbon isotope composition were developed at both sites and time-series verified against instrumental climate data over the period (AD 1960–AD 2002). Ring width sensitivity to summer temperature is site-dependent, with contrasting responses at alpine and lowland sites. Maximum density responds to September temperatures, suggesting lignification after cell division has ended for the season. Stable carbon isotopes have great potential, responding to summer temperature at oth alpine and lowland stands. Height increment appears relatively insensitive to climate, and is likely to be dominated by local stand dynamics

Snow Representation over Siberia in Operational Seasonal Forecasting Systems

Seasonal forecasting systems still have difficulties predicting temperature over continental regions, while their performance is better over some maritime regions. On the other hand, the land surface is a substantial source of (sub-)seasonal predictability. A crucial land surface component in focus here is the snow cover, which stores water and modulates the surface radiation balance. This paper’s goal is to attribute snow cover seasonal forecasting biases and lack of skill to either initialization or parameterization errors. For this purpose, we compare the snow representation in five seasonal forecasting systems (from DWD, ECMWF, Météo-France, CMCC, and ECCC) and their performances in predicting snow and 2-m temperature over a Siberian region against ERA5 reanalysis and station data. Although all systems use similar atmospheric and land initialization approaches and data, their snow and temperature biases differ in sign and amplitude. Too-large initial snow biases persist over the forecast period, delaying and prolonging the melting phase. The simplest snow scheme (used in DWD’s system) shows too-early and fast melting in spring. However, systems including multi-layer snow schemes (Météo-France and CMCC) do not necessarily perform better. Both initialization and parameterization are causes of snow biases, but, depending on the system, one can be more dominant

The effect of severe ground frost on Scots pine (Pinus sylvestris) trees in northern Finland and implications for palaeoclimate reconstruction

A severe frost event in the winter of 1986/1987 that resulted in widespread defoliation in northern Finland was used to test the influence of such growth disturbances on tree ring parameters commonly used for palaeoclimate reconstruction. In mature pine trees there was no effect on ring widths, latewood densities or on stable carbon isotope ratios. In young trees, however, the effect was immediate and prolonged, with a measurable increase in water stress for two years and a suppression of ring widths lasting for 6 to 7 years. There was no effect on latewood density. Where pine tree ring chronologies are used to reconstruct summer temperatures, the common practice of ignoring the juvenile years should ensure that severe frost events do not bias the reconstructions. However, extreme events may be important for understanding changes in forest dynamics, and changes in the magnitude, and frequency of such events may be important signals of human impact. The sensitivity of young pines makes them a potential archive for reconstructing past changes in growth disturbance events such as severe ground frosts

Correction of tree ring stable carbon isotope chronologies for changes in the carbon dioxide content of the atmosphere

Tree-ring stable carbon isotope ratios (δ13C) often display a decline over the industrial period (post-AD1850) that is only partly explained by changes in the isotopic ratio of carbon dioxide (CO2) and may represent a response to increased atmospheric concentrations of CO2 (ca). If this is not addressed, reconstructions using long tree-ring stable isotope chronologies calibrated using the modern period, for which meteorological records are available, may be compromised. We propose a correction procedure that attempts to calculate the δ13C values that would have been obtained under pre-industrial conditions. The correction procedure uses nonlinear (loess) regression but the magnitude of the adjustment made is restricted by two logical constraints based on the physiological response of trees: first, that a unit increase in ca cannot result in more than the same unit increase in the internal concentration of CO2 (ci), and second, that increases in water-use efficiency as a result of an increase in ca are limited to maintaining a constant ci/ca ratio. The first constraint allows retention of a falling trend in δ13C, which exceeds that which could logically be attributed to a passive response to rising ca. The second constraint ensures that any increase in δ13C, reflecting a change in water-use efficiency beyond maintenance of a constant ci/ca, is not removed. The procedure is tested using ‘pseudoproxies’, to demonstrate the effect of the correction on time-series with different shapes, and data from three sites in Finland and Norway. Two of the time-series retain a significant trend after correction, and in all three cases the correction improves the correlation with local meteorological measurements

IFN-α kinoid in systemic lupus erythematosus: results from a phase IIb, randomised, placebo-controlled study.

OBJECTIVE: To evaluate the efficacy and safety of the immunotherapeutic vaccine interferon-α kinoid (IFN-K) in a 36-week (W) phase IIb, randomised, double-blind, placebo (PBO)-controlled trial in adults with active systemic lupus erythematosus (SLE) despite standard of care. METHODS: Patients with SLE (185) with moderate to severe disease activity and positive interferon (IFN) gene signature were randomised to receive IFN-K or PBO intramuscular injections (days 0, 7 and 28 and W12 and W24). Coprimary endpoints at W36 were neutralisation of IFN gene signature and the BILAG-Based Composite Lupus Assessment (BICLA) modified by mandatory corticosteroid (CS) tapering. RESULTS: IFN-K induced neutralising anti-IFN-α2b serum antibodies in 91% of treated patients and reduced the IFN gene signature (p<0.0001). Modified BICLA responses at W36 did not statistically differ between IFN-K (41%) and PBO (34%). Trends on Systemic Lupus Erythematosus Responder Index-4, including steroid tapering at W36, favoured the IFN-K and became significant (p<0.05) in analyses restricted to patients who developed neutralising anti-IFN-α2b antibodies. Attainment of lupus low disease activity state (LLDAS) at W36 discriminated the two groups in favour of IFN-K (53% vs 30%, p=0.0022). A significant CS sparing effect of IFN-K was observed from W28 onwards, with a 24% prednisone daily dose reduction at W36 in IFN-K compared with PBO (p=0.0097). The safety profile of IFN-K was acceptable. CONCLUSIONS: IFN-K induced neutralising anti-IFN-α2b antibodies and significantly reduced the IFN gene signature with an acceptable safety profile. Although the clinical coprimary endpoint was not met, relevant secondary endpoints were achieved in the IFN-K group, including attainment of LLDAS and steroid tapering. TRIAL REGISTRATION NUMBER: NCT02665364