Recent Arctic ozone depletion: Is there an impact of climate change?

After the well-reported record loss of Arctic stratospheric ozone of up to 38% in the winter 2010–2011, further large depletion of 27% occurred in the winter 2015–2016. Record low winter polar vortex temperatures, below the threshold for ice polar stratospheric cloud (PSC) formation, persisted for one month in January 2016. This is the first observation of such an event and resulted in unprecedented dehydration/denitrification of the polar vortex. Although chemistry–climate models (CCMs) generally predict further cooling of the lower stratosphere with the increasing atmospheric concentrations of greenhouse gases (GHGs), significant differences are found between model results indicating relatively large uncertainties in the predictions. The link between stratospheric temperature and ozone loss is well understood and the observed relationship is well captured by chemical transport models (CTMs). However, the strong dynamical variability in the Arctic means that large ozone depletion events like those of 2010–2011 and 2015–2016 may still occur until the concentrations of ozone-depleting substances return to their 1960 values. It is thus likely that the stratospheric ozone recovery, currently anticipated for the mid-2030s, might be significantly delayed. Most important in order to predict the future evolution of Arctic ozone and to reduce the uncertainty of the timing for its recovery is to ensure continuation of high-quality ground-based and satellite ozone observations with special focus on monitoring the annual ozone loss during the Arctic winter.     

Is the recessional pattern of Himalayan glaciers suggestive of anthropogenically induced global warming?

Following the Intergovernmental Panel on Climate Change report of 2001, a hype regarding the future of Himalayan glaciers, flooding of Indo-Gangetic plains and coastal areas and drying of glacially fed rivers has been created. However, the recent studies of some of the Himalayan glaciers indicate that the rate of recession of most of the glaciers in general is on decline. These observations are in contradiction to the widely popularized concept of anthropogenically induced global warming. It is believed that the rise of temperature of around 0.6°C since mid-nineteenth century is a part of decadal to centennial-scale climatic fluctuations that have been taking place on this Earth for the past few thousands of years.     

Is geographical proximity necessary in the innovation networks in the era of global economy?

In the analysis of geographical spillovers, a commonly accepted hypothesis is that the different actors of innovation need to be physically closed to one another because the transfer of tacit knowledge implies frequent face-to-face relations. This hypothesis is put under closer examination in this paper. The first section analyses the need for economic agents to be closely located to develop research and innovative activities, starting with the analysis of their need for co-ordination and using some case studies. Based on the example of three French regions, the second section examines the importance given by the local development policies to geographical proximity in order to support the rapid development of local networks favouring innovation. In both sections, nonlocal relations appear as a key factor to develop innovation. As a conclusion, nonlocal relations should be encouraged by local development policies in the same way as local relations.     

Why is global warming slowing down?

It is established that the slowing down of global warming, which has been observed during the past decade, is due to the counteraction of natural factors and, primarily, to the reduction in solar activity and transition of the North Atlantic Oscillation to the regular negative phase. Warming is supposed to resume in the years to come, although at a lower rate than during the past 30 years.     

How global are the Jurassic–Cretaceous unconformities?

The reality of the global‐scale sedimentation breaks remains controversial. A compilation of data on the Jurassic–Cretaceous unconformities in a number of regions with different tectonic settings and character of sedimentation, where new or updated stratigraphic frameworks are established, permits their correlation. Unconformities from three large reference regions, including North America, the Gulf of Mexico, and Western Europe, were also considered. The unconformities, which encompass the Jurassic‐Cretaceous, the Lower–Upper Cretaceous and the Cretaceous–Palaeogene transitions are of global extent. Other remarkable unconformities traced within many regions at the base of the Jurassic and at the Santonian–Campanian transition are not known from reference regions. A correlation of the Jurassic–Cretaceous global‐scale sedimentation breaks and eustatic curves is quite uncertain. Therefore, definition of global sequences will not be possible until eustatic changes are clarified. Activity of mantle plumes is among the likely causes of the documented unconformities.     

Reassessment of global climate risk: non-compensatory or compensatory?

Natural Hazards - Evidence shows the global climate will continue to change over this century and beyond. A clear understanding of the climate change risk is suggested to be the foundation of the...     

Why would sea-level rise for global warming and polar ice-melt?

Two major causes of global sea level rise such as thermal expansion of the oceans and the loss of landbased ice for increased melting have been claimed by some researchers and recognized by the IPCC.However, other climate threat investigators revealed that atmosphere-ocean modeling is an imperfect representation, paleo-data consist of proxy climate information with ambiguities, and modern observations are limited in scope and accuracy. It is revealed that global warming and polar ice-melt although a reality would not contribute to any sea level rise. Floating-ice of the polar region on melting would reoccupy same displaced volume by floating ice-sheets. Land-ice cover in the polar region on melting can reduce load from the crust to activate elastic rebound that would raise land for its isostatic equilibrium.Such characteristics would not contribute to sea level rise. Equatorial bulge, polar flattening, elevation difference of the spheroidal surface between equator and pole with lower in the pole, strong gravity attraction of the polar region and week gravity attraction of the equatorial region, all these phenomena would play dominant role in preventing sea level rise. Palaeo-sea level rise and fall in macro-scale(10-100 m or so) were related to marine transgression and regression in addition to other geologic events like converging and diverging plate tectonics, orogenic uplift of the collision margin, basin subsidence of the extensional crust, volcanic activities in the oceanic region, prograding delta buildup, ocean floor height change and sub-marine mass avalanche. This study also reveals that geophysical shape, gravity attraction and the centrifugal force of spinning and rotation of the earth would continue acting against sea level rise.     

Local food sovereignty for global food security? Highlighting interplay challenges

The food sovereignty movement proposes a localist approach to meeting food security while delivering broader social, economic and environmental benefits. The movement is spawning multiple local projects of food sovereignty, whereby people are empowered to define their own culturally and environmentally appropriate food systems. As the number of enacted examples increases, the movement is also affecting change at national (and international) levels, with a number of countries creating national strategies or legislation for food sovereignty. We reflect on the challenges created by such scaling up within the existing food system. We propose a focus on issues of institutional interplay in order to identify and critique challenges. We highlight three interplay situations between multiple, diverse enactments of food sovereignty at multiple levels, and between food sovereignty and the broader institutional contexts within which they are embedded.     

Why would sea-level rise for global warming and polar ice-melt?

Two major causes of global sea level rise such as thermal expansion of the oceans and the loss of landbased ice for increased melting have been claimed by some researchers and recognized by the IPCC.However, other climate threat investigators revealed that atmosphere-ocean modeling is an imperfect representation, paleo-data consist of proxy climate information with ambiguities, and modern observations are limited in scope and accuracy. It is revealed that global warming and polar ice-melt although a reality would not contribute to any sea level rise. Floating-ice of the polar region on melting would reoccupy same displaced volume by floating ice-sheets. Land-ice cover in the polar region on melting can reduce load from the crust to activate elastic rebound that would raise land for its isostatic equilibrium.Such characteristics would not contribute to sea level rise. Equatorial bulge, polar flattening, elevation difference of the spheroidal surface between equator and pole with lower in the pole, strong gravity attraction of the polar region and week gravity attraction of the equatorial region, all these phenomena would play dominant role in preventing sea level rise. Palaeo-sea level rise and fall in macro-scale(10-100 m or so) were related to marine transgression and regression in addition to other geologic events like converging and diverging plate tectonics, orogenic uplift of the collision margin, basin subsidence of the extensional crust, volcanic activities in the oceanic region, prograding delta buildup, ocean floor height change and sub-marine mass avalanche. This study also reveals that geophysical shape, gravity attraction and the centrifugal force of spinning and rotation of the earth would continue acting against sea level rise.     

Is Dark Matter Needed in Galaxies?

Arguments indicating that galaxies and galaxy clusters should be considered open, forming systems are presented. Galaxies interact with the intergalactic medium, and are not in virial equilibrium (determined by gravitation and rotation). The usual interpretation of the rotation curves of the outer regions of galaxies beyond the visible stellar disk—that they imply the presence of a massive dark-matter halo— could be erroneous in this case: if the intergalactic medium is being accreted in these regions, the orbital speeds of clouds of neutral hydrogen will not be determined purely by the gravitation of the mass inside their orbits. Galaxy clusters accrete matter (intergalactic gas and galaxies) from the filaments of the large-scale structure at whose intersections they are located. Only their inner regions can approach virial equilibrium. Therefore, the high speeds of galaxies and the high temperature of the intergalactic gas in clusters does not necessarily imply the presence of a high mass of dark matter in galaxy clusters.     

Is flooding in Toronto a concern?

Toronto is the largest city in Canada with a population of about 5.5 million in the Greater Toronto Area (GTA). Being located at the shores of Lake Ontario of the Great Lakes, which is the largest surface freshwater system in the world, and affected by air masses originating from the Gulf of Mexico, the Atlantic Ocean, and the Arctic, the city is vulnerable to extreme weather phenomena in socioeconomic and geographical terms. This short paper gives a brief overview of the history of main flooding occurrences in Toronto with an emphasis on the recent flooding of July 2013. An analysis of causes and physical dynamics of the event is presented using the structure of the watersheds and weather systems in the region. Based on the flood risk vulnerability assessment carried out on the 2013 flooding, several weaknesses in critical infrastructure and critical facilities have been highlighted. Future considerations and recommendations include revisiting of the flood damage mitigation strategies (e.g., use of new and adaptive infrastructure designs, social media, crowd-sourcing information), flood zoning update, tax incentives, insurance options, and retrofitting solutions for those living in flood-prone areas.     

Is Lognormal Kriging Suitable for Local Estimation?

Lognormal kriging was developed early in geostatistics to take account of the often seen skewed distribution of the experimental mining data. Intuitively, taking the distribution of the data into account should lead to a better local estimate than that which would have been obtained when it is ignored. In practice however, the results obtained are sometimes disappointing. This paper tries to explain why this is so from the behavior of the lognormal kriging estimator. The estimator is shown to respect certain unbiasedness properties when considering the whole working field using the regression curve and its confidence interval for both simple or ordinary kriging. When examined locally, however, the estimator presents a behavior that is neither expected nor intuitive. These results lead to the question: is the theoretically correct lognormal kriging estimator suited to the practical problem of local estimation?     

Does the Agulhas Current amplify global temperatures during super‐interglacials?

Future projections of climate suggest our planet is moving into a ‘super‐interglacial’. Here we report a global synthesis of ice, marine and terrestrial data from a recent palaeoclimate equivalent, the Last Interglacial (ca. 130–116 ka ago). Our analysis suggests global temperatures were on average ～1.5°C higher than today (relative to the AD 1961–1990 period). Intriguingly, we identify several Indian Ocean Last Interglacial sequences that suggest persistent early warming, consistent with leakage of warm, saline waters from the Agulhas Current into the Atlantic, intensifying meridional ocean circulation and increasing global temperatures. This mechanism may have played a significant positive feedback role during super‐interglacials and could become increasingly important in the future. These results provide an important insight into a future 2°C climate stabilisation scenario. Copyright © 2010 John Wiley & Sons, Ltd.     

Can global rainfall estimates (satellite and reanalysis) aid landslide hindcasting?

Predicting rainfall-induced landslides hinges on the quality of the rainfall product. Satellite rainfall estimates or rainfall reanalyses aid in studying landslide occurrences especially in ungauged areas, or in the absence of ground-based rainfall radars. Quality of these rainfall estimates is critical; hence, they are commonly crosschecked with their ground-based counterparts. Beyond their temporal precision compared to ground-based observations, we investigate whether these rainfall estimates are adequate for hindcasting landslides, which particularly requires accurate representation of spatial variability of rainfall. We developed a logistic regression model to hindcast rainfall-induced landslides in two sites in Japan. The model contains only a few topographic and geologic predictors to leave room for different rainfall products to improve the model as additional predictors. By changing the input rainfall product, we compared GPM IMERG and ERA5 rainfall estimates with ground radar–based rainfall data. Our findings emphasize that there is a lot of room for improvement of spatiotemporal prediction of landslides, as shown by a strong performance increase of the models with the benchmark radar data attaining 95% diagnostic performance accuracy. Yet, this improvement is not met by global rainfall products which still face challenges in reliably capturing spatiotemporal patterns of precipitation events.

     

Is Salinity Variability a Benthic Disturbance in Estuaries?

Freshwater inflow is a driver of the functioning of estuaries, and average salinity is usually measured to identify the effects of inflow in salinity-zone habitats. However, salinity variability could act as a disturbance by producing unstable habitats, leading to the question: is salinity variance an indicator of benthic disturbance, and therefore a driver of community stability? The macrofauna communities of five estuaries that lie in a climatic gradient on the Texas coastline were analyzed using a 26-year data set. Comparisons within and between estuaries with different inflow regimes were used as a natural experiment to simulate press disturbance events (i.e., climatic inflow) and pulse disturbance (i.e., floods) in maintaining community stability. Salinity average and variance was compared with benthic community diversity, evenness, and species richness. Salinity variance was more correlated to benthic diversity for each estuarine system (r?=??0.6610; p?=?0.0015) than average salinity (r?=?0.3818; p?=?0.0967). As salinity variance decreased (i.e., stability increased), diversity levels of benthic communities increased, and areas with mgore freshwater inflow displayed lower levels of benthic diversity. These findings advance a component of the general theory of diversity maintenance that persistent stressors, such as salinity variability, can influence diversity.     

Is vegetation collapse on Borneo already in progress?

Natural Hazards - Vegetation and tropical forests in particular have a central role in mitigating the effects of increasing levels of atmospheric CO2. Photosynthesis is the fundamental process...