Science Progress

Since pollination by insects is vitally important for much of global crop production, and to provide pollination services more widely throughout the planetary ecosystems, the prospect of an imminent ‘pollination crisis’, due to a die-off of flying insects, is most disquieting, to say the least. Indeed, the term ‘ecological Armageddon’ has been used in the media. However, to know whether or not a wholesale decline in flying pollinators (including non-bee species) is occurring across the world is very difficult, due to an insufficiency of geographically widespread and long-term data. Bees, as the best documented species, can be seen to be suffering from chronic exposure to a range of stressors, which include: a loss of abundance and diversity of flowers, and a decline in suitable habitat for them to build nests; long-term exposure to agrochemicals, including pesticides such as neonicotinoids; and infection by parasites and pathogens, many inadvertently spread by the actions of humans. It is likely that climate change may impact further on particular pollinators, for example bumble bees, which are cool-climate specialists. Moreover, the co-operative element of various different stress factors should be noted; thus, for example, exposure to pesticides is known to diminish detoxification mechanisms and also immune responses, hence lowering the resistance of bees to parasitic infections. It is further conspicuous that for those wild non-bee insects – principally moths and butterflies – where data are available, the picture is also one of significant population losses. Alarmingly, a recent study in Germany indicated that a decline in the biomass of flying insects had occurred by 76% in less than three decades, as sampled in nature reserves across the country. Accordingly, to fully answer the question posed in the title of this article ‘pollinator decline - an ecological calamity in the making?’ will require many more detailed, more geographically encompassing, more species-inclusive, and longer-term studies, but the available evidence points to a clear ‘probably’, and the precautionary principle would suggest this is not a prospect we can afford to ignore.

In recent years, the problem caused by Tetra Pak waste (TPW) has became a topic of great concern to scientists and environmentalists, and commercial companies have also begun to take an interest in developing processes for tackling this issue. In this article, the challenges in the recycling of TPW are described. This article presents the major conclusions of previously published works focussed on the utilisation of TPW for energy and material purposes. The commercial utilisation of TPW is also described. Some suggestions for better recycling of TPW are given in the latter part of this work.

Carbon materials have been regarded as promising agents for hydrogen storage because of properties such as their light weight, acceptable affinity of carbon for hydrogen and high specific surface area. We can identify many different carbon materials which have been studied extensively such as activated carbons (AC) graphene sheets (GS), carbon nanotubes (CNTs) and other derivative carbon materials derived from theoretical and experimental methods such as g-C₃N₄, graphyne and carbon nanolayer. These materials can be modified by additional ingredients like free metals, metal oxides, and alloys to improve their hydrogen storage capacity. In this short review article, we attempt to introduce new, reliable, complete and categorised data for researchers concentrating on articles from the last five years (2013–2017) relating to hydrogen storage.