We present a data-driven emulator, a stochastic weather generator (SWG), suitable for estimating probabilities of prolonged heat waves in France and Scandinavia. This emulator is based on the method of analogs of circulation to which we add temperature and soil moisture as predictor fields. We train the emulator on an intermediate complexity climate model run and show that it is capable of predicting conditional probabilities (forecasting) of heat waves out of sample. Special attention is payed that this prediction is evaluated using a proper score appropriate for rare events. To accelerate the computation of analogs, dimensionality reduction techniques are applied and the performance is evaluated. The probabilistic prediction achieved with SWG is compared with the one achieved with a convolutional neural network (CNN). With the availability of hundreds of years of training data, CNNs perform better at the task of probabilistic prediction. In addition, we show that the SWG emulator trained on 80 years of data is capable of estimating extreme return times of order of thousands of years for heat waves longer than several days more precisely than the fit based on generalized extreme value distribution. Finally, the quality of its synthetic extreme teleconnection patterns obtained with SWG is studied. We showcase two examples of such synthetic teleconnection patterns for heat waves in France and Scandinavia that compare favorably to the very long climate model control run.

Extreme climate events such as heat waves are predicted to become more frequent with climate change, representing a challenge for many organisms. The pine processionary moth Thaumetopoea pityocampa is a Mediterranean pine defoliator, which typically lays eggs during the summer. We evaluated the effects of heat waves on egg mortality of three populations with different phenologies: a Portuguese population with a classical life cycle (eggs laid in summer), an allochronic Portuguese population reproducing in spring, and a Tunisian population from the extreme southern limit of T. pityocampa distribution range, in which eggs are laid in fall. We tested the influence of three consecutive hot days on egg survival and development time, using either constant (CT) or daily cycling temperatures (DT) with equivalent mean temperatures. Maximum temperatures (Tmax) used in the experiment ranged from 36 to 48°C for DT and from 30 to 42°C for CT. Heat waves had a severe negative effect on egg survival when Tmax reached 42°C for all populations. No embryo survived above this threshold. At high mean temperatures (40°C), significant differences were observed between populations and between DT and CT regimes. Heat waves further increased embryo development time. The knowledge we gained about the upper lethal temperature to embryos of this species will permit better prediction of the potential expansion of this insect under different climate warming scenarios.

The strong mechanistic relationship between climatic factors and seed dormancy and germination suggests that forecast climatic changes will significantly affect seed bank persistence. This review focuses on the potential impact of changing temperature, rainfall and fire regimes on the longevity of long-term persistent seed-banks. Currently, there are few studies investigating the mechanistic responses of demographic processes, such as seed-bank dynamics, to forecast climate change. However, from the work that has been published, several key points have been highlighted. First, increased air temperatures will produce significantly higher soil temperatures in open and sparsely vegetated habitats. Some evidence shows that this could accelerate the decline of seed viability and compromise bet-hedging strategies of species in dryland regions. Second, changes to rainfall season may determine the relative success of recruitment, with lower levels of success producing net losses to seed bank longevity. Finally, higher temperatures are likely to produce increased fire frequency, compromising the persistence of plant populations dependent on long-lived seed banks. Improving our understanding of both the mechanistic response and adaptive capacity of seed banks to climate change will provide a solid basis for improved predictions of future species distributions and risk of extinction, particularly in ecosystems subjected to temporally stochastic disturbances. It is necessary to develop functional groups based on key life-history trait responses to changing environmental conditions, to enable broader-scale predictions of distribution and persistence in the future.

Extirpation or even extinction of freshwater invertebrate species is a neglected conservation issue; declines in abundance and spatial distribution for freshwater invertebrates are far less documented than for vertebrate species. In the Minho River tidal freshwater wetlands (northwest of Iberian Peninsula), a rapid decline in density and biomass of the bivalve Pisidium amnicum was recorded at 16 different sites over seven years, from 2004 to 2010, without any sign of a potential recovery. Mean density values reached more than 80 ind.m−2 in 2004, but declined to less than 1 ind.m−2 in 2009 and 2010. An identical declining trend was observed for biomass. A significant reduction in the spatial distribution also occurred. The abiotic changes resulting from the 2005 heat wave and possibly the negative interactions imposed by the non-indigenous invasive bivalve Corbicula fluminea were the main factors responsible for the declining trends. Given the very low density, P. amnicum is facing a serious risk of extirpation in this ecosystem and conservational measures are urgently needed.

In ignition targets designs, U or U based cocktail hohlraum are usually used because the Rosseland mean opacity of U is higher than for Au at the radiation temperature for ignition. However, it should be noted that the opacity of U is obviously lower than for Au when the radiation temperature falls into a low temperature region. Because the depth penetrated by radiation is only several micrometers under a 300eV drive, and also because there is a prepulse longer than 10 ns prepulse at temperatures lower than 170 eV in the radiation drive of ignition target designs. Therefore we propose an Au + U + Au sandwich hohlraum for ignition targets in this work. Compared to the cocktail, the sandwich not only remarkably simplifies the fabrication and uses less depleted U material, but also increases the albedo during the prepulse.