The fundamental links between climate change and marine plastic pollution

Plastic pollution and climate change have commonly been treated as two separate issues and sometimes are even seen as competing. Here we present an alternative view that these two issues are fundamentally linked. Primarily, we explore how plastic contributes to greenhouse gas (GHG) emissions from the beginning to the end of its life cycle. Secondly, we show that more extreme weather and floods associated with climate change, will exacerbate the spread of plastic in the natural environment. Finally, both issues occur throughout the marine environment, and we show that ecosystems and species can be particularly vulnerable to both, such as coral reefs that face disease spread through plastic pollution and climate-driven increased global bleaching events. A Web of Science search showed climate change and plastic pollution studies in the ocean are often siloed, with only 0.4% of the articles examining both stressors simultaneously. We also identified a lack of regional and industry-specific life cycle analysis data for comparisons in relative GHG contributions by materials and products. Overall, we suggest that rather than debate over the relative importance of climate change or marine plastic pollution, a more productive course would be to determine the linking factors between the two and identify solutions to combat both crises

Sources, Distribution, and Fate of Microscopic Plastics in Marine Environments

Microplastics are pieces of plastic debris <5 mm in diameter. They enter the environment from a variety of sources including the direct input of small pieces such as exfoliating beads used in cosmetics and as a consequence of the fragmentation of larger items of debris. A range of common polymers, including polyethylene, polypropylene, polystyrene, and polyvinyl chloride, are present in the environment as microplastic particles. Microplastics are widely distributed in marine and freshwater habitats. They have been reported on shorelines from the poles to the equator; they are present at the sea surface and have accumulated in ocean systems far from land. Microplastics are also present in substantial quantities on the seabed. A wide range of organisms including birds, fish, and invertebrates are known to ingest microplastics and for some species it is clear that a substantial proportion of the population have microplastic in their digestive tract. The extent to which this might have harmful effects is not clear; however, the widespread encounter rate indicates that substantial quantities of microplastic may be distributed within living organisms themselves as well as in the habitats in which they live. Our understanding about the long-term fate of microplastics is relatively limited. Some habitats such as the deep sea may be an ultimate sink for the accumulation of plastic debris at sea; indeed, some recent evidence indicates quantities in the deep sea can be greater than at the sea surface. It has also been suggested that microplastics might be susceptible to biodegradation by microorganisms; however, this is yet to be established and the prevailing view is that even if emissions of debris to the environment are substantially reduced, the abundance of microplastics will increase over the next few decades. However, it is also clear that the benefits which plastics bring to society can be realized without the need for emissions of end-of-life plastics to the ocean. To some extent the accumulation of microplastic debris in the environment is a symptom of an outdated business model. There are solutions at hand and many synergistic benefits can be achieved in terms of both waste reduction and sustainable use of resources by moving toward a circular economy

THE SOURCES AND FATE OF PLASTIC ENTERING THE MARINE ENVIRONMENT

Plastics can come in many forms and bring a wide range of societal benefits in healthcare, agriculture, transport, construction and packaging. However, plastic is a large proportion of marine litter and an internationally recognised pollutant. Marine litter results from the indiscriminate disposal of waste items that are either directly or indirectly transferred into aquatic environments. This debris can cause harmful effects for wildlife, commercial fisheries, maritime industries, tourism and human well-being (Chapter 1). Over the past decade, increased scientific interest has produced an expanding knowledge base for plastic contamination in the environment. However, fundamental questions and issues remain unresolved. This thesis addresses several prominent sources of plastic litter and discusses the routes by which the plastic can enter the environment; these include facial scrubs, laundering clothes, wet wipes and carrier bags. Whilst the emphasis of this thesis is on microplastics (both primary and secondary source), the indiscriminate disposal of macroplastics are also considered, as, with time, they have the potential to degrade into secondary microplastics. Cosmetic products, such as facial scrubs, were identified as a potentially important primary sources of microplastics to the marine environment. Up to 94500 microplastics were found to release in a single use (Chapter 2). The laundering clothes was also found to be an important source of primary microplastic where over 700,000 fibres were estimated to be released from an average 6 kg wash load (Chapter 3). Wet wipes degradability was tested for both flushable and non-flushable alternatives. There are currently no standardised criteria to measure whether a product can be flushed, and the degradability of these products still remains unclear (Chapter 4). Furthermore, different formulations of carrier bags that stated that they were biodegradable and oxo-biodegradable, were still present in the soil and marine environment after 3 years. This suggests that they have no meaningful advantage over conventional bags in terms of consequences of persistence. (Chapter 5). The versatility, low cost and often single use application of plastic mean that the material is utilised for a wide variety of products. Therefore, one of the major challenges in addressing the issues surrounding marine plastic debris is the diverse nature of plastic products and the many routes by which they can enter the environment. To help manage and reduce emissions it is essential to better understand the relative importance of these sources, assess regional variation and target specific solution options (Chapter 6)

A Perspective of the Cumulative Risks from Climate Change on Mt. Everest: Findings from the 2019 Expedition

In 2019, the National Geographic and Rolex Perpetual Planet Everest expedition successfully retrieved the greatest diversity of scientific data ever from the mountain. The confluence of geologic, hydrologic, chemical and microbial hazards emergent as climate change increases glacier melt is significant. We review the findings of increased opportunity for landslides, water pollution, human waste contamination and earthquake events. Further monitoring and policy are needed to ensure the safety of residents, future climbers, and trekkers in the Mt. Everest watershed

A Perspective of the Cumulative Risks from Climate Change on Mt. Everest: Findings from the 2019 Expedition

In 2019, the National Geographic and Rolex Perpetual Planet Everest expedition successfully retrieved the greatest diversity of scientific data ever from the mountain. The confluence of geologic, hydrologic, chemical and microbial hazards emergent as climate change increases glacier melt is significant. We review the findings of increased opportunity for landslides, water pollution, human waste contamination and earthquake events. Further monitoring and policy are needed to ensure the safety of residents, future climbers, and trekkers in the Mt. Everest watershed

Correction: Message in a bottle: Open source technology to track the movement of plastic pollution.

[This corrects the article DOI: 10.1371/journal.pone.0242459.]