Abstract

Efforts to make food systems more sustainable have emphasized reducing adverse environmental impacts of agriculture. In contrast, chemical and biological processes that could produce food without agriculture have received comparatively little attention or resources. Although there is a possibility that someday a wide array of attractive foods could be produced chemosynthetically, here we show that dietary fats could be synthesized with <0.8 g CO2-eq kcal−1, which is much less than the >1.5 g CO2-eq kcal−1 now emitted to produce palm oil in Brazil or Indonesia. Although scaling up such synthesis could disrupt agricultural economies and depend on consumer acceptance, the enormous potential reductions in greenhouse gas emissions as well as in land and water use represent a realistic possibility for mitigating the environmental footprint of agriculture over the coming decade.

Abstract

Long-distance passenger travel has received rather sparse attention for decarbonization. Here we characterize the long-distance travel pattern in England and explore its importance on carbon emissions from and decarbonization of passenger travel. We find that only 2.7% of a person’s trips are for long distance travel (>50 miles one-way), but they account for 61.3% of the miles and 69.3% of the greenhouse gas (CO2 equivalent) emissions from passenger travel, highlighting its importance for decarbonizing passenger transport. Long-distance travel per person has also been increasing over time, trending in the opposite direction to shorter-distance travel. Flying for leisure and social purposes are the largest contributors to long distance miles and emissions, and these miles are also increasing. Overall, per capita travel emissions have started decreasing slowly from 2007, but are still higher than in 1997. We propose a new metric—emissions reduction sensitivity (% emission reduced/% trips altered)—to understand the efficiency of travel demand related initiatives to reduce greenhouse gas emissions. Long-distance travel—especially flying—can offer orders of magnitude larger emissions reduction sensitivity compared with urban travel, which suggests that a proportionate policy approach is necessary.

Abstract

Lithium-ion batteries (LiBs) are used globally as a key component of clean and sustainable energy infrastructure, and emerging LiB technologies have incorporated a class of per- and polyfluoroalkyl substances (PFAS) known as bis-perfluoroalkyl sulfonimides (bis-FASIs). PFAS are recognized internationally as recalcitrant contaminants, a subset of which are known to be mobile and toxic, but little is known about environmental impacts of bis-FASIs released during LiB manufacture, use, and disposal. Here we demonstrate that environmental concentrations proximal to manufacturers, ecotoxicity, and treatability of bis-FASIs are comparable to PFAS such as perfluorooctanoic acid that are now prohibited and highly regulated worldwide, and we confirm the clean energy sector as an unrecognized and potentially growing source of international PFAS release. Results underscore that environmental impacts of clean energy infrastructure merit scrutiny to ensure that reduced CO2 emissions are not achieved at the expense of increasing global releases of persistent organic pollutants.

Abstract

The Younger Dryas (YD) cold reversal interrupts the warming climate of the deglaciation with global climatic impacts. The sudden cooling is typically linked to an abrupt slowdown of the Atlantic Meridional Overturning Circulation (AMOC) in response to meltwater discharges from ice sheets. However, inconsistencies regarding the YD-response of European summer temperatures have cast doubt whether the concept provides a sufficient explanation. Here we present results from a high-resolution global climate simulation together with a new July temperature compilation based on plant indicator species and show that European summers remain warm during the YD. Our climate simulation provides robust physical evidence that atmospheric blocking of cold westerly winds over Fennoscandia is a key mechanism counteracting the cooling impact of an AMOC-slowdown during summer. Despite the persistence of short warm summers, the YD is dominated by a shift to a continental climate with extreme winter to spring cooling and short growing seasons.

Abstract

Across the last ~50,000 years (the late Quaternary) terrestrial vertebrate faunas have experienced severe losses of large species (megafauna), with most extinctions occurring in the Late Pleistocene and Early to Middle Holocene. Debate on the causes has been ongoing for over 200 years, intensifying from the 1960s onward. Here, we outline criteria that any causal hypothesis needs to account for. Importantly, this extinction event is unique relative to other Cenozoic (the last 66 million years) extinctions in its strong size bias. For example, only 11 out of 57 species of megaherbivores (body mass ≥1,000 kg) survived to the present. In addition to mammalian megafauna, certain other groups also experienced substantial extinctions, mainly large non-mammalian vertebrates and smaller but megafauna-associated taxa. Further, extinction severity and dates varied among continents, but severely affected all biomes, from the Arctic to the tropics. We synthesise the evidence for and against climatic or modern human (Homo sapiens) causation, the only existing tenable hypotheses. Our review shows that there is little support for any major influence of climate, neither in global extinction patterns nor in fine-scale spatiotemporal and mechanistic evidence. Conversely, there is strong and increasing support for human pressures as the key driver of these extinctions, with emerging evidence for an initial onset linked to pre-sapiens hominins prior to the Late Pleistocene. Subsequently, we synthesize the evidence for ecosystem consequences of megafauna extinctions and discuss the implications for conservation and restoration. A broad range of evidence indicates that the megafauna extinctions have elicited profound changes to ecosystem structure and functioning. The late-Quaternary megafauna extinctions thereby represent an early, large-scale human-driven environmental transformation, constituting a progenitor of the Anthropocene, where humans are now a major player in planetary functioning. Finally, we conclude that megafauna restoration via trophic rewilding can be expected to have positive effects on biodiversity across varied Anthropocene settings.

Abstract

Permaculture is proposed as a tool to design and manage agroecological systems in response to the pressing environmental challenges of soil degradation, climate change and biodiversity loss. However, scientific evidence on the effects of permaculture is still scarce. In this comprehensive study on a wide range of soil and biodiversity indicators, we examined nine farms utilizing permaculture and paired control fields with locally predominant agriculture in Central Europe. We found 27% higher soil carbon stocks on permaculture sites than on control fields, while soil bulk density was 20% lower and earthworm abundance was 201% higher. Moreover, concentrations of various soil macro- and micronutrients were higher on permaculture sites indicating better conditions for crop production. Species richness of vascular plants, earthworms and birds was 457%, 77% and 197% higher on permaculture sites, respectively. Our results suggest permaculture as effective tool for the redesign of farming systems towards environmental sustainability.

Abstract

The eminent protein sources among the vegetarian population include cereals and pulses that do not satisfy the Recommended Dietary Allowance (RDA) level. The anti-nutrients such as protease inhibitors are responsible for the diminished bioavailability of plant protein. Consumption of a protein deficit diet severely impacts muscle health; hence, it becomes necessary to design an alternative source of complete protein. One such non-meat source with all essential amino acids in required quantity is seaweeds, an aquatic plant. The unique flavour and umami taste possessed by seaweeds notably enhance consumer acceptability. The principal focus of this review was on novel food products, digestibility, quality of protein, and consumer satisfactoriness of consuming seaweeds. The yield of seaweed obtained is based on the aquaculture system's type, location, season, and other environmental conditions, which is a significant challenge faced during extraction. This hurdle may prevail via unconventional extraction procedures summarized in this review. Subsequently, the consumers are becoming health conscious, seaweed-based food products are predicted to have excellent market potential. It is concluded that seaweeds can potentially contribute to future global security in functional foods and nutraceuticals.