Geology for Global Development

Robert Emberson

Robert Emberson: Microplastic – Too Important to Ignore

Anyone lucky enough to catch any of the BBC’s recent new series Blue Planet II will have noticed that each episode devotes a portion of the time to the impact humans have on the oceans. A breathtaking series of shots from a recent episode detailed the heart-wrenching demise of a baby whale, possibly poisoned by its mother’s milk due to toxins from plastic pollution. Vast quantities of plastic now cover the surface of the ocean, a point the series makes well. We’re now increasingly aware of the risks this plastic introduces, but there’s one part of the problem that scientists have only recently begun to appreciate – so called ‘microplastic’.

Toothpaste is a notorious source of ‘microbeads’.

Microplastic is simply defined as those bits of plastic waste smaller in length than 5mm. This famously includes ‘microbeads’ used in some cosmetics and toothpastes, but there’s also contribution from artificial fabric fibres and degraded bits of larger plastic waste. Because we often can’t see the microplastic with our naked eyes, it goes much more unheralded in contrast to the floating islands of waste bottles and packaging, but that invisibility makes it a more insidious monster.

We still don’t know much about the sources and pollutant pathways associated with microplastic. The United Nations Environment program suggest that cosmetic sources of microbeads have been a pollutant for at least the last 50 years but since then it has often been forgotten as a potential pollutant. In recent years researchers have observed river and ocean sediments in a number of global locations with high levels of microplastic accumulation, while a collaborative investigation between journalists and scientists has revealed that a significant proportion of tapwater in a wide range of urban settings contains measurable microplastic. It seems, then, that this is a problem of growing importance.

The impact for biology is also an emerging subject of study. Microplastic can accumulate either physically in organisms or the toxins generated as it breaks down can poison creatures all across the food chains. Ecologists regularly note the potential for pollutants and toxins to become more concentrated in species further up the food chain, and this is just as true for microplastics. In addition, the plastic compounds have the potential to adsorb other toxins and contaminants onto their surfaces; this mechanism of pollution delivery is poorly understood but considering that the smaller the plastic fragments the greater the proportion of surface area that could be utilised in this way, it could well play a role.

From a sustainability perspective, these plastic fragments could be a timebomb. Not only do they pollute water systems and potentially contribute to poisoning aquatic species, but the impacts could grow for years to come. Even if in the future we shift to a more sustainable model of consumption and production, and recycle the majority of the plastic we use, we will still have to deal with a microplastic legacy of our current plastic use. At present, we have only recycled or incinerated around 20% of our plastic waste meaning that the remaining 80% could disintegrate into fragments over time. It’s clear that understanding how this material enters our water systems and ecosystems is thus of paramount importance.

Microplastic particles on a beach. Image credit: NOAA

And here’s where geologists can play a role. River systems are a topic of interest and study for so many earth scientists, whether geochemists, hydrologists, or geomorphologists. Many geologists routinely sample rivers to analyse the amount of sediment within, or the chemical fluxes. Microplastic fits within the same areas of study; it has been described as a “structural” rather than chemical pollutant – which essentially means it forms part of the solid load of a river – just like regular sediment. Naturally, the physical properties of the plastic differ to sand or clay (the difference in density is particularly important), but the methods we could use to calibrate our microplastic models would be similar to those used to assess suspended or bedload in rivers.

Some scientists are already using these techniques, but much more work needs to be done to effectively understand the long term evolution of the fragments in natural waters. How, for example, do storms and floods affect the storage or mobilisation of microplastic in river sediments? Using hydrological tools to fingerprint the sources of microplastic might also help form a better picture of where exactly these pollutants enter the water systems, which still in many locations remains a mystery. Hydrological models incorporating microplastic transport would certainly help ecologists plan for the impact pollutants would have on aquatic species, and this is exactly what hydrologists could bring to the table.

The adsorption of chemicals to the surface of plastic is similar to other particles in the water flow – particularly colloids. Recent studies have shown that microplastic can adsorb heavy metals (another key set of pollutants) onto their surfaces, and thus deliver these pollutants to a range of species that might ingest the plastic. These are processes well understood by geochemists, offering a chance for the geochemistry community to collaborate with ecologists and conservation researchers.

As with a number of the issues standing in the way of achieving the Sustainable Development Goals, addressing microplastic pollution will require extensive cooperation between scientists of different stripes, policy makers, and polluters. A recent study suggests both that plastics from road wear by cars are the biggest contributor in parts of Europe and that sewage treatment efficiency is an important variable. Resolving these kind of complex infrastructure and ecological problems should certainly engage a cross-section of researchers.

Geologists can find their role in solving this problem as scientists, but importantly as regular citizens too. Limiting plastic use and advocating for recycling are already part of the arsenal of tools we can use to improve the sustainability of our lives; geologists shouldn’t forget that they can contribute in these ways too. Research is still ongoing to understand the range of products and plastics that either contain or form microplastic pollution, but we should all keep track of this research to ascertain how we can minimise our microplastic footprint. We need drinking water more than any other resource, and keeping it unpolluted by tiny plastic particles is an imperative.

Robert Emberson is a science writer, currently based in Victoria, Canada. He can be contacted via Twitter (@RobertEmberson) or via his website (www.robertemberson.com).

Robert Emberson: Geomythology – Why understanding cultural traditions of landscape are important for sustainable development

Every culture has myths and legends about their native lands. Before we understood the geological forces that forced up great ranges of mountains or sculpted barren deserts, humans needed an explanation for the scale and majesty of natural phenomena. Stories of deities inhabiting volcanoes, or angry gods shaking the very ground upon which people lived, helped people make sense of disasters when tectonic forces were unimagined. Since the advent of the scientific method, and secularised science, such tales are often forgotten when we look at a landscape; why resort to a story when the facts say otherwise?

Devil’s Tower, Wyoming. Image courtesy psaudio / Pixabay

In some cases, it’s true that such stories don’t offer geologists much factual evidence about how the landscape formed. Even beautiful stories about features like the Devil’s Tower, in Wyoming, USA; the ancestral tale tells of people pursued by a giant bear; once they had reached the top of the peak, the bear could not reach them, but the scratch marks on the sides were testament to its attempts. Today, we know these are classic examples of columnar jointing. Although we might enjoy the story, it definitely doesn’t tie to the more modern understanding!

But there are some instances where we should perhaps pay more attention to myths, and particularly in the context of geology and sustainable development. While the tangible evidence of geological processes are often visible at a grand scale, it’s also true that the signals or proxies we look for to understand these processes can be very scarce. Trace fossils, or small shifts in element abundances, for example; we should take advantage of every shred of evidence we can find. As a result, some scientists have been turning to ancestral stories – in particular those about catastrophic events – for information.

Researchers have found tantalising clues about past events in mythical tales, and it seems often there is no smoke without fire. Amongst other studies, geologists have found evidence of volcanism in previously thought-dormant Pacific Volcanoes from local accounts, and evidence of giant floods in China, partly linked to tales of Emperor Yu 4000 years ago. The cultural memory of such giant catastrophes is etched into the myths told there; it seems that using these stories could help us better establish the timing and recurrence of natural disasters, allowing for improved risk analysis and development in tune with natural events.

There’s another, perhaps even more important aspect of geological myths to bear in mind for sustainable development. It’s increasingly well understood that the best approaches taken to encourage development, economic or otherwise, will differ across the world, driven by cultural differences. Development anthropologists could point to studies (e.g. see here) indicating that the definition of quality of life varies widely to suggest that a local approach would be the most sensible in approaching development, rather than assuming a standard ‘western’ approach would work everywhere.

The relationship of people to their landscape is, for the same reasons, an important variable to consider when discussing development. For example, Mt Machapuchare in Nepal is of special significance to Hindus, and as such is off-limits to climbers (and indeed has never been summitted). It is not the only mountain steeped in myth in the Himalayas,  and as such, it would be a mistake to assume that the burgeoning tourist industry could operate freely on every mountain. Similarly, the recent decision to ban tourists from climbing Uluru in Australia may not make economic sense, but consideration of cultural associations clearly is more important.

Some of these cases may seem isolated. But every culture has its own unique relationship with land, which is to some degree (big or small) influenced by myth and legend. Applying the same development strategy in each setting is misguided – and to me it seems this is particularly true for the modern concept of treating the landscape as a commodity to be exploited for profit. Indigenous peoples (in Canada, for example) have treated the land they depend on in a highly sustainable fashion, informed by their cultural memory of fables and myth. We may not be able to return to such a state of living in the modern era, but if we want to build a more sustainable economy and change our current ‘business as usual’ model, it would be fitting to look to those cultures that have achieved a sustainable fashion of living – and particularly fitting to ask ourselves what about their cultural memory encouraged them to live that way.

Robert Emberson is a science writer, currently based in Victoria, Canada. He can be contacted via Twitter (@RobertEmberson) or via his website (www.robertemberson.com).

Robert Emberson: Soil Erosion and Sustainable Development

Over the last few weeks we’ve introduced you to some new faces on the GfGD blog, including Robert Emberson, Heather Britton and Jesse Zondervan. Today, Robert (based in Victoria, Canada) writes on the connections between soil erosion and sustainable development, and poses the question – is soil one of our most threatened resources? 

When we talk about sustainable energy sources, most of the time we’re referring to renewable sources of electricity and heat. Geothermal, solar, wind or waves – these are all sources of energy that are, within practical limits, not exhausted by our use. However, all living species need more than just electricity and heat as energy; we need food to sustain us.

The vast majority of food for humans requires agriculture, whether vegetable crop or grazing species. Agriculture depends completely on fertile soil to succeed, but we often don’t think about soil as a resource that really matters. Crucially, however, the rate at which soil forms is vastly outpaced by the rate it erodes away in modern farming. For all intents and purposes, soil is a non-renewable resource, like fossil fuels.

A recently published UN study has highlighted this, estimating that 24 billion tons of fertile soil is lost annually every year – primarily in sub-Saharan Africa. The implications for sustainable production of food are obvious, with some studies suggesting we only have an average of 60 years’ worth of harvests left under the current practices.

We shouldn’t ignore the inherent potential of this crisis to exacerbate existing economic inequalities, too; according to the study authors “critically unbalanced land productivity trends in African cropland and grasslands are particularly concerning given expected population growth.”  This, in fact, highlights the most worrying trend; even as soil is eroded away, and the amount of cropland dwindles, the global population increases apace, with 9 billion mouths to feed estimated by 2050.

Farming in Uganda (Source: GfGD)

Moreover, the UN study emphasises that degradation of soil and loss of agricultural land increases the competition for already-scarce resources, which could lead to mass migration or social instability, further increasing the difficulty of implementing sustainable solutions.

So how has the problem become so acute? It is useful to first explain how soil erosion occurs naturally, before thinking about how humans have impacted the natural cycles. Roughly, natural soils form as the result of chemical breakdown of underlying bedrock, supplemented by organic matter decaying from dead plants and animals. In a stable system, the rate at which soils are produced is in balance with the rate at which water washes away surface material during floods and storms.

In some parts of the world, where warm, wet, conditions are ideal for plant growth and chemical reactions, soil can grow extremely fast – as much as 2.5mm per year, although the global average is nearer to 0.1mm per year.

Water is the primary agent that erodes the soil. Whenever rain falls, droplets can dislodge material, and these can be washed away downhill or carried in floodwaters over landscape. It’s no surprise, then, that soils through which water can more easily infiltrate are less likely to lose material to overland flow. However, humans have fundamentally altered this balance.

Natural forests allow water to infiltrate into soil quickly, but without root systems and porous soil this can be much lower. For example, in Wales scientists demonstrated that forested plots had infiltration rates 67 times faster than sheep pastures. Agricultural land is similar, or can be worse; if there are no crops to bind the soil together for some parts of the year, or if ploughing churns up the soil and allows material to be easily washed away, topsoil can be severely depleted in a single flood.

These two factors – lack of plant cover, and extensive tillage – are hallmarks of high intensity farming globally, but as the UN study points out, while this kind of farming has increased productivity over the last decades, it is increasingly unsustainable. Addition of fertiliser has increased the productivity, but masked the degradation of arable land. Moreover, in some regions it creates a viscous cycle, where loss of productive land leads to deforestation to access untapped soil.

Forests are key buffers against many slow and fast moving disasters; they can limit flooding, by encouraging water to infiltrate rather than running over landscape, and in doing so can allow more water to reach aquifers – thus limiting drought later. They also serve important roles in stabilising hill-slopes against landslides, and slow desertification. Given how long it takes for forest to regrow, it seems clear that the impact of soil loss will be felt for years to come.

So what can be done to prevent it? And how can geologists act to help address the problem, particularly how we can still achieve sustainability goals in the face of the rapid loss of life-giving topsoil? An integrative approach is certainly important. Soil is the interface where life, at a microbial and macro-scale, coexists with physical and chemical processes in the bedrock. Understanding how all of these fit together is crucial to build a clearer picture of the at-risk soil.

Sustainable rehabilitation of agricultural land has been achieved at a wide scale in some countries, like Ethiopia. Surface process geologists could help by producing maps of local and regional propensity for erosion, to help guide these efforts. Scientists from the Kenya-based World Agroforestry Centre have been hard at work producing for the first time maps of soil chemistry and health across sub-Saharan Africa, and these should similarly help to more efficiently utilise the soil for particular crops, and aid in crop choice for a given location, if appropriately combined with crop biology assessments.

The authors of the UN study explain that increasing the efficiency of agriculture would certainly alleviate some of the stress on croplands. Improvements in efficacy can be found at different points throughout the food supply chain; for example, the authors write that:

“Eliminating food waste would reduce the projected need to increase the efficiency of food production by 60 per cent to meet expected demands by 2050”.

Meat uses five times as much land for a given nutritional intake than the comparable vegetable option, so reducing the intake of meat, along with other nutritionally inefficient crops (like soy and palm oil) would distinctly reduce the amount of cropland needed to feed 9 billion people. These solutions are politically sensitive, of course, but scientists can make informed decisions about their own food choices, and encourage others to do the same.

Above all, given how important soil is to land surface processes, many geologists could ask themselves which aspects of their own knowledge might help alleviate this significantly under-reported problem. While we have alternative, renewable energy sources to turn to instead of fossil fuels, we don’t yet have an alternative to soil, and as such it’s perhaps imperative to think about soil as one of our most threatened resources.

Robert Emberson is a science writer, currently based in Victoria, Canada. He can be contacted via Twitter (@RobertEmberson) or via his website (www.robertemberson.com).

**This article expresses the personal opinion of the author. These opinions may not reflect official policy positions of Geology for Global Development.**

Introducing Our New Authors (1) – Robert Emberson

Over the next few weeks we’d like to introduce you to some new faces on the GfGD blog, bringing fresh ideas and perspectives on topics relating to geoscience and sustainable development. We’re delighted to have their input, and look forward to their posts. Today we interview Robert Emberson – based in Victoria, Canada. 

Hi there! Who are you?

I’m Robert Emberson, and I’m delighted to be volunteering for GfGD. I’m looking forward to blogging about a range of topics; I see earth science at the intersection with society and social goals to be among the most challenging and interesting topics to communicate, to both scientists and the wider public.

I’m currently working as a science writer, based in Victoria, Canada. Previously I worked as an associate editor at Nature Geoscience, and before that I completed a PhD in Geomorphology at the University of Potsdam in Germany.

How did you become interested in the work of GfGD?

Some of my friends from undergraduate study were involved in the project for many years, so I have been aware of what GfGD does for some time. I’ll be honest, though – 5 or so years ago, when I started my PhD, my attention was taken up by topics that were less relevant to development and society.

Over the course of my doctoral work, though, that attitude changed. I studied the effect of bedrock landslides on chemical weathering in mountain belts, and in doing so I was fortunate to conduct fieldwork in some rapidly eroding mountain belts. It’s impossible to visit places like Nepal and Taiwan and study the landslides there without coming away with some sense of how much risk the people living under unstable hillslopes must undertake in their daily lives. Landslide hazard is just one example of an earth science problem that has very real implications for people in developing regions, and I now feel strongly that it’s imperative as scientists not to ignore these implications.
So in a roundabout way this led me to GfGD; using earth science knowledge to help achieve the Sustainable Development Goals aligns well with my own interests, and I’m delighted to have this opportunity to contribute.

What role do you think science communication has in achieving the Sustainable Development Goals?

When I worked at Nature Geoscience, one of the concepts I used on a regular basis is that it should be possible for a communicator of science to be able to describe any topic, to any audience, in (almost) any number of words. The trick, of course, is to make it engaging for your audience. It seems clear to me that the SDGs are relevant to everyone, in most cases directly. Effective science communication can explain the scientific basis for this relevance (e.g. look at the links between food security and climate change, and how that affects the supply chain for the meal you’re having for dinner tonight) in a way that makes it interesting and engaging to a wide audience.

An engaged audience is one that is more likely to take action; we should use the scientific research as a powerful ally to persuade folks of the benefit of attaining the SDGs. This goes both ways, too; effective communication of the links between geoscience and SDGs should encourage a greater proportion of scientists to think about the implications of their own work for sustainability.

What topics are you most excited about at the moment?

I’ve been reading extensively lately about ground-source heating (where the earth is used as a heat source or sink for a central heating or cooling system) in the context of the changing climate. Over the next century, really dangerous temperatures could become the norm in some parts of the world, so access to air conditioning could be a matter of life and death. Using the shallow subsurface as a heat sink seems a pretty basic geological concept, but it doesn’t seem to be widely discussed; but increasing the efficiency of cooling might help alleviate the potential inequality of access to air conditioning.

I’m also interested in the long-lived effects of disasters on sustainability. Working on landslides has given me a chance to study risk and hazard ‘in between’ catastrophes. The stability of a hillslope can be changed for years after an earthquake, for example, and this changes the risk of a landslide for many years afterwards. We often imagine the impact of a disaster to be immediate, but we also often expect things should settle back to normal later on. But what if the disaster changes what normal means (i.e. the boundary conditions)? This could really important for agriculture or soil loss, or groundwater systems. This certainly seems like a place where geosciences could help inform policy.

What will you blog about?

Hopefully, all sorts of things! Images and human stories are a fantastic way to start discussions about science, and are something I’d like to work on. I’d like to look at deep-dives into more niche but nevertheless important topics; the kind of subjects and research papers that don’t necessarily fit the categorisation for ‘headline news’ but have implications for sustainability and development for whole swathes of people. The ground-source heating example above is just such an idea.

Any other interests?

I’m curious about how science is conducted, and if we can improve the way we work and publish. Equality and representation in science have parallels to the SDGs, and I think it’s valuable to think about whether we can use science as a microcosm to achieve these goals more widely. I’m also an advocate for increasing trust in science through opening our work to the public – and not just at final publication stage.

When I’m not working, I spend as much time as I can outside; I’m lucky to live for now in British Columbia, where there’s great opportunities to hike, climb and trail run in the forests and mountains.

Robert Emberson can be contacted via Twitter: @RobertEmberson or via his website: www.robertemberson.com

**This article expresses the personal opinions of the author (Robert Emberson). These opinions may not reflect an official policy position of Geology for Global Development. **