By rethinking the way our products are designed and changing the way we use plastics, we can tackle the blight of marine litter and the general accumulation of plastic waste. But, as Professor Richard Thompson said in our latest SCItalk, systemic issues and historical excesses have made this no easy task.

Contrary to popular perception, plastic is not the villain. When it comes to marine littering, we are the ogres, with our single-use bottles bobbing in the oceans and the detritus of our everyday lives littering the coastline.

We are the reason why 700 species are known to encounter plastic debris in the environment. It is because of us that plastics have beaten us to the bottom of the deepest oceans and glint in the sun near the summit of Mt. Everest.

According to Richard Thompson, of the Marine Institute School of Biological and Marine Sciences at the University of Plymouth: ‘Plastic debris is everywhere. Its quantity in the ocean is likely to triple between 2015 and 2025.’

As Professor Thompson pointed out all of these facts to his audience in our latest SCItalk on 23 March, he outlined potential solutions. However, there is no ignoring the depth of the issues at hand when it comes to the litter in our seas.

The problems

1 - The weight of history

Society has gradually woken up to the menace of discarded plastics and, laterally, to the threat of microplastics and nanoplastics. The problem is that we left the barn door open decades ago. So, all of those plastic microbeads from shower gels, fibres from clothing, and tyre wear particles polluted our seas for many years before it came to public and scientific attention.

Professor Thompson said that 300 papers were published globally on microplastics in the last academic year alone, but research in the area was relatively thin on the ground before Thompson and his colleagues released their pioneering study on microplastics in Science in 2004.

2 - Bad habits

‘The business model for the use of plastics hasn’t really changed since the 1950s,’ Professor Thompson said. According to him, we have had 60 years of behavioural training to just throw products away, and our waterways reflect this attitude.

According to Professor Thompson, 50% of shoreline litter items recorded during the 2010s originated from single-use applications. Without a sea change in our attitude towards single-use items, this problem will persist.

>> Why are we ignoring climate change and what can we do about it? Read more on our blog post.

Microplastics have been subject to great scrutiny, but much of the research is quite recent.

3 - We need to talk about nanoplastics

The problems with larger plastics and even microplastics are now well documented. The worrying thing, according to Thompson, is that there are knowledge gaps when it comes to nanoplastics in the natural environment. What are the effects of nanoplastic ingestion? What are the effects of human health? Time will tell, but Thompson was keen to ask if we really need that information before we take action.

He was more sanguine about the effects of microplastics. ‘The concentration of microplastics is probably not yet causing widespread ecological harm,’ he said, ‘but if we don’t take measures, we’ll pass into widespread ecological harm within the next 50-100 years.’

The solutions

It seems counterintuitive to think of petrochemical plastics as a sustainable solution; and yet, despite the environmental problems posed by their durability, they do have a role to play in a greener approach.

‘If used responsibly, plastics can reduce our footprint on the planet,’ Thompson noted. Indeed, the lightweight plastic parts in our cars and in aviation can actually help reduce carbon emissions. But despite their merits, how do we keep plastic litter from our seas?

1 - Design for end of life… and a new one

To illustrate a flaw in the way we design plastic products, Professor Thompson gave the example of an orange coloured drinks bottle. While the bright colour may help sell juice drinks, there is an issue with recycling these coloured plastics because their value as a recyclate is lower. Clear plastics, on the other hand, are much more viable to recycle.

He argues that many products aren’t being designed with the whole lifecycle in mind. ‘We’re still failing to get to grips with linking design to end of life,’ he said, before highlighting the importance of communicating how products should be disposed of right from the design stage.

Basically, our products should be designed with end of life in mind. ‘If we haven’t even designed a plastic bottle properly,’ he lamented, ‘what hope do we have with something that’s more complicated?’

Those brightly coloured plastic bottles look nice and fancy, but they can be challenging to recycle in a circular economy.

2 - Ever recycle? Ever fail? Recycle again. Recycle better

Professor Thompson argued that better practices are needed to help divert materials away from our seas (and it should be noted that there are other types of discarded materials to be found there). If we recycle greater quantities of end of life plastic products and bring them into a circular economy, he said, ‘we’d decouple ourselves from oil and gas as the carbon source for new production because the carbon source we use would be the plastic waste’.

He said more could also be done with labelling so that customers know whether, for example, a product is compostable and which waste stream it needs to be placed in to achieve that. He also noted that addressing our single-use culture would be a good place to start if we want to change the business model of linear use.

3 - Broaden the discussion and pull those policy levers

The good news is that there is an appetite for change. ‘Ten years or so ago there was no consensus that there was a problem,’ Thompson noted. ‘I would argue that this has changed.’ However, he also feels that it is essential to gather reliable, independent evidence to inform interventions, rather than espousing solutions that could make things worse.

‘We need to gather that evidence from different disciplines,’ he said. ‘We need to have at the table product designers and couple them with the waste managers. We need to have economists at the table. We also need to bring in social scientists to look at behaviour. We’ve got to think about this in the round.’

He also felt that policy measures – such as mandating recycled content – could be a good option, along with better design and disposal.

The tools we need to tackle plastic pollution are already at our disposal. We just need to act more responsibly – which, unfortunately, has been part of the problem all along.

As Professor Thompson said: ‘It’s not the plastics per se that are the problem – it’s the way we’ve chosen to use them.’

>> For more interesting SCI talks like Professor Thompson’s, check out our YouTube channel.

>> Find out more about the work of Professor Thompson and his colleagues here: https://www.plymouth.ac.uk/research/marine-litter.

Crop rotation, seaweed extracts, lime, and a range of organic materials can all improve soil health and crop yields. Professor Geoff Dixon shows you several ways to improve your soil.

Rapidly rising costs of living are affecting all aspects of life. Increasing costs of fertilisers are affecting food production, both commercially and in gardens and allotments.

Wholesale prices of fertilisers have jumped four-fold from £250 to £1,000 per tonne within six months. All forms of garden fertilisers are now much more expensive. Crops, especially vegetables, only thrive if provided with adequate nutrition (see nitrogen-deficient lettuce below). Consequently, fertiliser use must become more efficient.

Nitrogen deficiency in lettuce.

Healthy, fertile soils achieved through good management are key to this process. That ensures roots can take up the nutrients needed in quantities that result in balanced, healthy growth.

Soil pH is a major regulator of nutrient availability for roots. Between pH 6.5 to 7.5, the macro nutrients, nitrogen, phosphorus, and potassium are fully available for root uptake. Below and above these values, nutrient absorption becomes less efficient.

>> How much soil cultivation do you need for your vegetables? Find out more in Prof Dixon's blog on cultivation.

As a result, soluble nutrients are wasted and washed by rainfall below the root zones. Acidic soils can be improved by liming in the autumn. Sources of lime derived from crushed limestone require up to six months to cause changes in soil pH values. Lime should be used in ornamental gardens with caution as it can result in micronutrient deficiencies.

Iron deficiency in wisteria.

Soil health and fertility are greatly increased by adding organic materials such as farmyard manure and well-made composts. Increasing soil carbon content helps mitigate climate change while raising fertiliser use efficiencies.

Beneficial soil biological life such as earthworms, insects, benign bacteria and fungi are greatly encouraged when you increase soil humus content. Using crop rotations, which include legumes, raises natural levels of soil nitrogen. This is a result of legumes’ symbiotic relationships with nitrogen-fixing bacteria.

Leafy vegetables such as brassicas require large amounts of nitrogen and, hence, should follow legumes in a rotation. Avoiding soil compaction encourages adequate aeration, benefiting root respiration and providing oxygen for other organisms.

Organic materials are of great value in ornamental gardens when applied as top dressings in late autumn or early spring. This provides two benefits: a slow release of nutrients into the root zones as decomposition occurs, and prevention of weed growth.

Inorganic fertiliser use can be further minimised by using proprietary seaweed extracts. These contain macro- and micro-nutrients plus several natural biostimulant compounds that aid healthy ornamental plant growth and flowering (illustration no 3 rose Frűhlingsgold).

Rose frűhlingsgold

Written by Professor Geoff Dixon, author of Garden practices and their science.

We always hear about athletes eking out that competitive edge through subtle changes in diet or equipment. Well, when it comes to making our buildings more energy-efficient, dozens of different technologies could make a difference. Every one may not be earth juddering on its own, but each could help decarbonise our homes by degrees.

Phase-changing materials (PCMs) may have a role to play in reducing our reliance on power-hungry cooling and heating systems in the home. At Texas A&M University, researchers have developed PCMs to passively regulate temperatures inside buildings.

They believe their 3D-printed phase-change materials - compounds that can change from a solid to liquid when absorbing heat, or from liquid to solid when releasing heat - could be incorporated into our homes in paint or other interior effects to regulate interior temperatures.

New phase-change material composites can regulate ambient temperatures inside buildings | Image credit: Texas A&M University College of Engineering

Their partial substitute to the heating, ventilation and air conditioning (HVAC) systems that predominate in many of our buildings is a light-sensitive liquid resin with a phase-changing paraffin wax powder.

According to the researchers, their 3D printable ink composite improves upon existing PCMs in that it doesn’t require a separate shell around each PCM particle. When the PCM is mixed with liquid resin, the resin acts as both the shell and building material, enabling thermal energy management without any leakage. They use an ultraviolet light to solidify their 3D printable paste and make it suitable for use in our buildings.

“The ability to integrate phase-change materials into building materials using a scalable method opens opportunities to produce more passive temperature regulation in both new builds and already existing structures,” said Dr. Emily Pentzer, associate professor in the Department of Materials Science and Engineering and the Department of Chemistry.

To date, the researchers have only tested their materials on a small scale in a house-shaped model. Nevertheless, after placing their 3D printed model inside an oven, the results were encouraging. The model’s temperature was 40% different to outside temperatures compared to models made using traditional materials.

From solar panels and insulation to heat pumps and phase change materials, much has been done to make our homes more energy-efficient

“We’re excited about the potential of our material to keep buildings comfortable while reducing energy consumption,” said Dr. Peiran Wei, research scientist in the Department of Materials Science and Engineering and the Soft Matter Facility. “We can combine multiple PCMs with different melting temperatures and precisely distribute them into various areas of a single printed object to function throughout all four seasons and across the globe.”

Perhaps we won’t see PCMs in widespread use in our buildings any time soon, but it’s always heartening to see the use of passive heating and cooling systems in our buildings. Anything that contributes to the decarbonisation mix is certainly worth investigating further.

Think of Earth as an apple and the soil as the peel. Now, imagine that more than 70% of this apple’s surface is covered in water. That veneer of peel suddenly seems very small indeed.

Dig beneath the surface and you realise that the world’s soil resources aren’t as plentiful as you first thought. When you take into account all of the uninhabitable, non-arable land on our planet, including the snow-bound poles and deserts, you’re left with just 3% of total landmass to grow all the fruit and vegetables we eat.

After reminding her listeners of some stark facts at the Soil resources in the UK: overlooked and undervalued? webinar, Jane Rickson, Professor of Soil Erosion and Conservation at Cranfield University, reminded us that soil is a precious, finite resource. “We’re dealing with a very thin resource that has to deliver all of these goods and services.”

You just need to think of your breakfast, lunch, and dinner to realise just how important soil is. Of all the food we eat, 97% comes from terrestrial sources. However, in recent decades, the many benefits brought by soil have been taken lightly. Apart from providing food, animal fodder, and a surface for football, it plays a vital role in climate change mitigation.

‘Soil is excellent for climate change mitigation,’ said Professor Rickson, recipient of the prestigious Dr Sydney Andrew Medal for 2021. ‘We know that healthy soils can support vegetation and crops and plants in taking out atmospheric CO2.’

A cross section of soil layers. Unless you live on fish and seaweed, it’s likely that almost all of your food sources will come from terrestrial sources.

However, she and her colleagues at Cranfield University have unearthed some unsettling facts about the state of our soils. She mentioned that 12 million hectares of agricultural land worldwide is lost each year due to soil degradation. In the UK, soil erosion rates can be as high as 15 tonnes per hectare per year, with soil formation rates only compiling at a rate of 1 tonne per hectare per year; and, based on current rates of erosion, some soils could disappear completely by 2050.

So, what is being done to arrest this problem? The obvious mammoth in the room is climate change, with extreme weather events such as flash floods precipitating a huge amount of soil erosion. Obviously, climate change mitigation measures on a national scale would help, but adjustments to farming practices could also improve soil resilience on a more local level.

A lot of work is also being done to reduce the intensity of farming to improve soil health. The aim, according to Rickson, is to maintain a fertile seedbed while retaining maximum resistance to soil degradation. There are lots of different ways to do this.

One approach being taken is cover cropping, whereby a crop is grown for the protection and enrichment of the soil rather than for immediate sale. This enriches the soil and helps prevent soil erosion. Another approach is strip-tillage – a minimum tillage system that disturbs only the portion of the soil that contains the seed row, with the soil between rows left untilled. She also mentioned the benefits of soil improvement, with poultry manure and mushroom compost used to improve soil health by Benedict Unagwu among others.

Cover crops such as vetch and oats improve the structure and fertility of the soil.

It is difficult not to have sympathy for farmers at the moment. Climate change falls heavily upon their lands, and they must battle flooding and drought to keep their farms financially viable. Professor Rickson often speaks to the farming community about soil health, with the focus placed on realistic solutions. As one farmer told her: ‘It's hard to be green when you’re in the red.’

Perhaps soil doesn’t capture the imagination the same way as an oak forest or a field ablaze with wildflowers, but its mismanagement is costing us a fortune. She estimated that the combined annual economic cost of soil degradation in England, Scotland, and Wales is £1.5 billion.

According to Professor Rickson, the US is probably the home of soil conservation following the harsh ecological lessons learnt from the Dust Bowl disaster of the 1930s. However, she believes the UK has plenty of knowhow in the area.

‘The UK has an opportunity to be world-leading in this,’ she said. ‘I think we are as good as anyone. Our scientific community understands soil and is really pushing the boundaries in terms of soil science.’

We’re starting to see those silent cars everywhere. The electric vehicle evolution is gradually seeping onto our roads. Every month or two, we also seem to read about another wind power generation record in the UK, or some super solar cell. Pension funds and big corporations are coming under great pressure to divest from fossil fuels. The clean power revolution is well underway.

And yet the third biggest polluter of the planet - after power and transport - awaits the seismic shift that will shake it to its foundations. Indeed, cement production still accounts for roughly 8% of the world’s greenhouse gas emissions.

The problem is that creating cement is an energy-intense, polluting process with firing temperatures of 2,700 degrees Fahrenheit needed to create it, and plenty of CO₂ released during processing.

Green cement and concrete are needed to reduce emissions in construction and other industries.

But there are signs that the processing could become cleaner. A recent report released by Market Research Future (MRFR) predicts that concrete (of which cement is a key ingredient) use could get appreciably greener over the next six years. It estimates that the global green concrete market size will grow at a 9.45% compound annual growth rate from 2020-27.

MRFR attributes this rise to several factors. First, there is a growing demand for green or recycled concrete (that incorporates waste components) within the construction industry. For builders, it enhances their environmental credentials and will increasingly become a business-savvy investment as governments seek to reduce carbon emissions.

Green building codes and the creation of energy-efficient infrastructure will also help propel this growth, and changing building regulations in massive markets including China, India, and the Middle East will result in many manufacturers looking to develop different material combinations. Increasingly, we’re seeing manufacturers turning to less energy-intensive manufacturing methods and investigating which waste materials could be used to create a greener cement or concrete that doesn’t compromise on performance.

Researchers at Chalmers University of Technology, in Sweden, have even been developing a rechargeable cement-based battery. If it ever comes to pass, this could be used to create buildings that store energy like giant batteries. Some manufacturers are also looking into the electrification of kilns, which isn’t feasible yet, and carbon capture and storage has long been mooted as a means to reduce industrial emissions.

Imagine an entire twenty storey concrete building that can store energy like a giant battery. This could be possible if Chalmers University’s cement-based rechargeable batteries come to fruition. | Image Credit: Yen Strandqvist/Chalmers University of Technology

The good news is that we don’t just have people all over the world working on low-carbon materials and manufacturing methods; experts in the UK are tackling the issue right now. On 2 June, speakers at the SCI’s free webinar, Ultra-low carbon concrete, a sustainable future, will examine some of the exciting initiatives underway.

These include an award winning, industry accepted ultra-low carbon alternative to traditional cement, which could result in CO2 savings of up to 78%, and the potential of using offsite manufacturing to provide commercial projects with a sustainable structural frame solution.

As with transport and power, cement is getting greener increment by increment. But with drastic climate change consequences dangling above us like the Sword of Damocles, now is the time for concrete action.

Register for Ultra-low carbon concrete, a sustainable future today at: https://bit.ly/33WfjkN.

Sometimes, when you try to solve one problem, you create another. A famous example is the introduction of the cane toad into Australia from Hawaii in 1935. The toads were introduced as a means of eliminating a beetle species that ravaged sugar cane crops; but now, almost a century later, Western Australia is inundated with these venomous, eco-system-meddling creatures.

In a similar spirit, disposable face masks could help tackle one urgent problem while creating another. According to researchers at Swansea University, nanoplastics and other potentially harmful pollutants have been found in many disposable face masks, including the ones some use to ward off Covid-19.

After submerging various types of common disposable face masks in water, the scientists observed the release of high levels of pollutants including lead, antimony, copper, and plastic fibres. Worryingly, they found significant levels of pollutants from all the masks tested.

Microscope image of microfibres released from children's mask: the colourful fibres are from the cartoon patterns | Credit: Swansea University

Obviously, millions have been wearing single-use masks around the world to protect against the Covid-19 pandemic, but the release of potentially harmful substances into the natural environment and water supply could have far-reaching consequences for all of us.

‘The production of disposable plastic face masks (DPFs) in China alone has reached approximately 200 million a day in a global effort to tackle the spread of the new SARS-CoV-2 virus,’ says project lead Dr Sarper Sarp, whose team’s work has been published on Science Direct. ‘However, improper and unregulated disposal of these DPFs is a plastic pollution problem we are already facing and will only continue to intensify.

The presence of potentially toxic pollutants in some face masks could pose health and environmental risks.

‘There is a concerning amount of evidence that suggests that DPFs waste can potentially have a substantial environmental impact by releasing pollutants simply by exposing them to water. Many of the toxic pollutants found in our research have bio-accumulative properties when released into the environment and our findings show that DPFs could be one of the main sources of these environmental contaminants during and after the Covid-19 pandemic.’

The Swansea scientists say stricter regulations must be enforced during manufacturing and disposal of single-use masks, and more work must be done to understand the effect of particle leaching on public health and on the environment. Another area they believe warrants investigation is the amount of particles inhaled by those wearing these masks.

‘This is a significant concern,’ adds Sarp, ‘especially for health care professionals, key workers, and children who are required to wear masks for large proportions of the working or school day.’

Every tin can dropped into our recycling bins is a small act of faith. We hope each one is recycled, yet the figures take some of that fervour from our faith. According to UK government statistics from 2015-2018, only about 45% of our household waste is recycled. Similarly, the UN has noted that only 20% of the 50 million tonnes of electronics waste produced globally each year is formally recycled. So, it’s fair to say we could do better.

Thankfully, thousands of people around the globe are working on these problems and two recent developments give us grounds for optimism. The first involves upcycling metal waste into multi-purpose aerogels, and the second involves fully recyclable printed electronics that include a wood-derived ink. 

Upcycling metal waste

Researchers at the National University of Singapore (NUS) claim to have turned one person’s trash into treasure with a low-energy way to convert aluminium and magnesium waste into high value aerogels for the construction industry.

To do this, they ground the metal waste into a powder and mixed it with chemical cross-linkers. They heated this mixture in an oven before freeze-drying it and turning it into an aerogel. The team says this simple process makes their aerogels 50% cheaper than commercially available silica aerogels.

Aerogels have many useful properties. They are absorbent, extremely light (hence the frozen smoke nickname), and have impressive thermal and sound insulation capabilities. This makes them useful as thermal insulation materials in buildings, in piping systems, or for cleaning up oil spills. However, the NUS team has loftier goals than that.

There is a great need for less energy intensive ways to recycle metals

“Our aluminium aerogel is 30 times lighter and insulates heat 21 times better than conventional concrete,” research team leader Associate Professor Duong Hai-Minh whose research has been published in the Journal of Material Cycles and Waste Management. “When optical fibres are added during the mixing stage, we can create translucent aluminium aerogels which, as building materials, can improve natural lighting, reduce energy consumption for lighting and illuminate dark or windowless areas. Translucent concrete can also be used to construct sidewalks and speed bumps that light up at night to improve safety for pedestrians and road traffic.”

The aerogels could even be used for cell cultivation. Professor Duong explains: “Microcarriers are micro-size beads for cells to anchor and grow. Our first trials were performed on stem cells, using a cell line commonly used for testing of drugs as well as cosmetics, and the results are very encouraging.”

Whatever about these speculative applications, this upcycling method will hopefully help us find new homes for all types of metal waste including metal chips and discarded electronics.

Recyclable printed electronics

A team at Duke University has also made interesting progress in reducing electronic waste. The researchers claim to have developed fully recyclable printed electronics that could be used and reused in a wide range of sensors.

The researchers’ transistor is made from three carbon-based inks that can be printed onto paper, and their use of a wood-derived insulating dielectric ink called nanocellulose helps make them recyclable. Carbon nanotubes and graphene inks are also used for the semiconductors and conductors, respectively.

A 3D rendering of the first fully recyclable, printed transistor.
CREDIT: Duke University

“Nanocellulose is biodegradable and has been used in applications like packaging for years,” said Aaron Franklin, the Addy Professor of Electrical and Computer Engineering at Duke, whose research has been published in Nature Electronics. “And while people have long known about its potential applications as an insulator in electronics, nobody has figured out how to use it in a printable ink before. That’s one of the keys to making these fully recyclable devices functional.”

The team has developed a way to suspend these nanocellulose crystals (extracted from wood fibres) with a sprinkling of table salt to create an ink that performs well in its printed transistors. At the end of their working life, these devices can be submerged in baths with gently vibrating sound waves to recover the carbon nanotubes and graphene components. These materials can be reused and the nanocellulose can be recycled just like ordinary paper.

The team conceded that these devices won’t ruffle the trillion dollar silicon-based computer component market, but they do think these devices could be useful in simple environmental sensors to monitor building energy use or in biosensing patches to track medical conditions.

Read about the Duke University research here: https://www.nature.com/articles/s41928-021-00574-0
Take a look at the NUS study here: https://link.springer.com/article/10.1007/s10163-020-01169-1

To some, the almond is a villain. This admittedly tasty nut takes an extraordinary amount of water to grow (1.1 gallons per nut) and some in California say almond cultivation has contributed to drought.

And so it is no surprise to see the almond lined up in the rogue’s gallery of the thirstiest foods. In a study in the journal Nature Food, University of Michigan (U-M) and Tulane University researchers assessed how the food we eat affects water scarcity.

Meat consumption was found to be the biggest culprit in the US, with the hooves and feet of livestock accounting for 31% of the water scarcity footprint. Within the meat category, beef is the thirstiest, with almost six times more water consumption than chicken.

Almond crops in California have come under heavy criticism due to their heavy water consumption

However, the picture is a little more nuanced. Lead author Martin Heller, of U-M's School for Environment and Sustainability, explains: “Beef is the largest dietary contributor to the water scarcity footprint, as it is for the carbon footprint. But the dominance of animal-based food is diminished somewhat in the water scarcity footprint, in part because the production of feed grains for animals is distributed throughout less water-scarce regions, whereas the production of vegetables, fruits and nuts is concentrated in water-scarce regions of the United States, namely the West Coast states and the arid Southwest.”

Certain types of diets drain the water supply. People who eat large quantities of beef, nuts such as the infamous almond, walnut, and cashew, and a high proportion of water-intense fruits and vegetables including lemon, avocado, asparagus, broccoli, and cauliflower take a heavy toll on the water footprint.

The Brussels sprout is not just for Christmas… it is a less water intense option for your dinner table.

“The water-use impacts of food production should be a key consideration of sustainable diets,” adds study co-author Diego Rose of Tulane University. “There is a lot of variation in the way people eat, so having a picture with this sort of granularity – at the individual level – enables a more nuanced understanding of potential policies and educational campaigns to promote sustainable diets.”

So, what do you do the next time you feel a pang of water guilt? According to the researchers, you could swear off asparagus and that crushed avocado on your toast and replace them with less water intense foods such as fresh peas, Brussels sprouts, cabbage, and kale (but maybe not on your toast). Those beef steaks and hamburgers could make way for other protein sources, such as chicken, pork, and soybeans, and you could graze on peanuts and seeds instead of those honey roasted almonds you love so dearly. Just think of all those gallons of water you’ll save.

For more on this study, visit: https://www.nature.com/articles/s43016-021-00256-2

What do grape stalks, pineapple leaves, corn cobs, rice husks, sheep’s wool, and straw have in common? Apart from being natural materials, they have all been used to insulate homes. Increasingly, people are turning towards natural, sustainable materials as climate change and waste have become bigger problems.

Existing building insulation materials such as synthetic rock wool are excellent at keeping our homes warm in winter, but the conversation has moved beyond thermal performance. Energy use, re-usability, toxicity, and material disposal are all live considerations now, especially with regulations and emissions targets tightening. So, rock wool might perform better than straw bale insulation but straw is biodegradable, reusable, easy to disassemble, and doesn’t require large amounts of energy to process.

Sheep’s wool and hemp insulation have also become attractive to homeowners and housebuilders alike, but an even more encouraging prospect is the use of waste materials to create next generation insulation. In this spirit, researchers at Flinders University in Adelaide, Australia, have taken waste cooking oil, wool offcuts, and sulphur to process a novel housing insulation material.

Recycled paper is one of many waste materials that has found its way into domestic insulation.

To make this composite, they followed several stages. In the first stage of the synthesis, the researchers used inverse vulcanisation to create a polysulphide polymer from canola oil triglyceride and sulphur. They then mixed this powdered polymer with wool and coated the fibres through electrostatic attraction. This mixture was compressed through mild heating to provoke S−S metathesis in the polymer and bind the wool. The wool bolsters the tensile strength of the material, makes it less flammable, and provides excellent insulation. The result is a sustainable building material that fulfils its function without damaging the environment.

For Associate Professor Justin Chalker, the lead author of this study, this work provides an ideal jumping-off point. “The promising mechanical and insulation properties of this composite bodes well for further exploration in energy saving insulation in our built environment,” he said.

Sustainable transformation

It is clear that ventures like the one in Adelaide will continue to sprout all over the world. After all, necessity dictates that we change the way we build our homes and treat materials.

A recent report from Emergen Research predicts that the global insulation materials market will be worth US $82.96 billion (£59.78 billion) by 2027. The same report was also at pains to mention that the increasing demand for reduced energy consumption in buildings will be a significant factor in influencing industry growth.

“Market revenue growth is high and expected to incline rapidly going ahead due to rising demand for insulation materials... to reduce energy consumption in buildings,” it said. One of the main reasons given for this increased green building demand was stricter environmental regulations.

And Emergen isn’t the only organisation feeling the ground moving. Online roofing merchant Roofing Megastore, which sells more than 30,000 roofing materials, has detected a shift towards environmentally friendly materials, with many homeowners sourcing these products themselves.

Rock wool insulation panels have come under greater scrutiny in recent times.

Having analysed two years of Google search data on sustainable building materials, the company found that synthetic roof tiles are generating the most interest from the public. Like the Flinders insulation, these roof tiles make use of waste materials, in this case recycled limestone and plastic. And you don’t need to look far down the list to find sustainable insulation materials, with sheep’s wool insulation in 9th place, wood fibre insulation in 10th, and hemp insulation in 12th.

Over time, the logic of the progression towards natural, less energy-intensive building materials will become harder to ignore. “Traditional materials such as synthetic glass mineral wool offer high levels of performance but require large amounts of energy to produce and must be handled with care while wearing PPE,” the company noted. “Natural materials such as hemp or sheep’s wool, however, require very little energy to create and can be installed easily without equipment.”

So, the next time you look down at your nutshells, spent cooking oil, or tattered woollen sweater, think of their potential. In a few years, these materials could be sandwiched between your walls, keeping you warm all winter.

Insulating composites made from sulphur, canola oil, and wool (2021): https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cssc.202100187?af=R

Rising anxiety about air pollution, physical, and mental health, exacerbated by Covid-19 and concerns about public transport, has seen an increase in the popularity of cycling around Europe, leading many cities to transform their infrastructure correspondingly.

These days, Amsterdam is synonymous with cycling culture. Images of thousands of bikes piled up in tailor-made parking facilities continue to amaze and it is routinely held up as an example of greener, cleaner, healthier cities. Because The Netherlands is so flat, people often believe it has always been this way. But, in the 1970s, Amsterdam was a gridlocked city dominated by cars. The shift to cycling primacy took work and great public pressure.

For some cities, however, the pandemic has provided an unexpected opportunity on the roads. Milan's Deputy Mayor for Urban Planning, Green Areas and Agriculture, Pierfrancesco Maran, has explained that, "We tried to build bike lanes before, but car drivers protested". Now, however, numbers have increased from 1,000 to 7,000 on the main shopping street. "Most people who are cycling used public transport before”, he said. “But now they need an alternative”.

Creating joined up cycling networks is a major challenge for urban planners.

In Paris, the Deputy Mayor David Belliard does not seem concerned that the city’s investment since the start of the pandemic will go to waste. “It's like a revolution," he said. “Some sections of this road are now completely car-free. The more you give space for bicycles, the more they will use it.” They are committed to creating a cycle culture, providing free cycling lessons and subsidising the cost of bike repairs. The city intends to create more than 650km of cycle lanes in the near future.

The success in these two cities has been supported by local government but it has also been fuelled by an understandable (and encouraged) avoidance of public transport and fewer cars on the road generally. Going forward, however, it seems likely that those last two factors won’t be present. So how do you create a cycling culture in your city in the long run?

The answer is both simple and difficult: cyclists (and pedestrians) need to have priority over cars. In Brussels, where 40km of cycle track have been put down in the last year, specific zones have been implemented where this is the case, and speed limits have been reintroduced across the city.

In Copenhagen, in the late 1970s, the Danish Cyclists’ Federation arranged demonstrations demanding more cycle tracks and a return to the first half of the century, when cyclists had dominated the roads. Eventually, public pressure paid off — although there is still high demand for more cycle lanes. A range of measures, including changes made to intersections, make cyclists feel safer and local studies show that, as cyclist numbers increase, safety also increases. In many parts of the city, it is noticeable how little of the wide roads are actually available to cars: bikes, joggers, and pedestrians are all accommodated.

Segregated cycleways, like this one in Cascais, Portugal, make people more likely to cycle.

But, if you were starting from scratch, you might not simply add cycle lanes to existing roads and encourage behavioural changes on the road. Segregated, protected bike lanes like those introduced in Paris are the next level up and the results suggest they work — separated from the roads, more people are inclined to try cycling.

Dutch experts suggest, where possible, going even further. Frans Jan van Rossem, a civil servant specialising in cycling policy in Utrecht, believes the best option is to create solitary paths, separated from the road by grass, trees, or elevated concrete. Consistency is also important. Cities need networks of cycle tracks, not just a few highways. Again, prioritising cyclists is key to the Dutch approach. Many cities have roads where cars are treated as guests, restricted by a speed limit of 30km/hour and not permitted to pass. Signage is also key.

In London, Mayor Sadiq Khan’s target is for 80% of journeys to be made by walking, cycling, and/or public transport by 2041. Since 2018, the city has been using artificial intelligence to better understand road use in the city and plan new cycle routes in the capital. However, the experience of other European capitals suggests that, "if you build it, they will come" might be a better approach than working off current usage.

A completely clean, renewable energy system that can be produced locally and that can easily power heat, energy storage and transportation, and travel — that's the future that promoters of a hydrogen economy envisage.

If it sounds a bit like rocket science, that's because it is. Hydrogen is what's used to fuel rockets — that’s how powerful it is. In fact, it’s three times more powerful as a fuel than gas or other fossil-based sources. And, after use, it’s frequently converted to drinking water for astronauts.

US President Joe Biden has highlighted the potential of hydrogen in his ambitious plans for economic and climate recovery and a number of recent reports have been encouraging about hydrogen’s breakthrough moment, including McKinsey and Company (Road Map to a US Hydrogen Economy, 2020) and the International Energy Agency.

Hydrogen fuel cells provide a tantalising glimpse into our low-carbon future

The McKinsey report claims that, by 2030, the hydrogen sector could generate 700,000 jobs and $140bn in revenue, growing to 3.4 million jobs and $750bn by 2050. It also believes it could account for a 16% reduction in CO2 emissions, a 36% reduction in NOx emissions, and supply 14% of US energy demand.

So how does it work?

Simply put, hydrogen fuel cells combine hydrogen and oxygen atoms to produce electricity. The hydrogen reacts with oxygen across an electrochemical cell and produces electricity, water, and heat.

This is what gets supporters so excited. In theory, hydrogen is a limitless, incredibly powerful fuel source with no direct emissions of pollutants or greenhouse gases.

So what's the problem?

Right now, there are actually a few problems. The process relies on electrolysis and steam reforming, which are extremely expensive. The IEA estimates that to produce all of today’s dedicated hydrogen output from electricity would require 3,600TWh, more than the total annual electricity generation of the European Union.

Moreover, almost 95% of hydrogen currently is produced using fossil fuels such as methane, natural gas, or coal (this is called "grey hydrogen"). Its production is responsible for annual CO2 emissions equivalent to those of Indonesia and the United Kingdom combined. In addition, its low density makes it difficult to store and transport — it must be under high pressure at all times. It’s also well-known for being highly flammable — its use as a fuel has come a long way since the Hindenburg Disaster but the association still makes many people nervous.

A Hydrogen refuelling station Hafencity in Hamburg, Germany. Infrastructure issues must be addressed if we are to see more hydrogen-fuelled vehicles on our roads. | Image credit: fritschk / Shutterstock.com

So there are quite a few problems. What’s the good news?

In the last few years, we've seen how rapidly investment, innovation, and infrastructure policy can completely transform individual renewable energy industries. For example, the IEA analysis believes the declining costs of renewables and the scaling up of hydrogen production could reduce the cost of producing hydrogen from renewable electricity 30% by 2030.

Some of the issues around expense could be resolved by mass manufacture of fuel cells, refuelling equipment, and electrolysers (which produce hydrogen from electricity and water), made more likely by the increased interest and urgency. Those same driving forces could improve infrastructural issues such as refuelling stations for private and commercial vehicles, although this is likely to require coordination between various stakeholders, including national and local governments, industry, and investors.

The significant gains in renewable energy mean that “green” hydrogen, where renewable electricity powers the electrolysis process, is within sight.

The IEA report makes clear that international co-operation is “vital” to progress quickly and successfully with hydrogen energy. R&D requires support, as do first movers in mitigating risks. Standards need to be harmonised, good practice shared, and existing international infrastructure built on (especially existing gas infrastructure).

If hydrogen can be as efficient and powerful a contributor to a green global energy mix as its proponents believe, then it's better to invest sooner rather than later. If that investment can help power a post-Covid economic recovery, even better.

Broad beans are an undemanding and valuable crop for all gardens. Probably originating in the Eastern Mediterranean and grown domestically since about 6,000BC, this plant was brought to Great Britain by the Romans.

Header image: a rich harvest of succulent broad beans for the table

Capable of tolerating most soil types and temperatures they provide successional fresh pickings from June to September. Early crops are grown from over-wintered sowings of cv Aquadulce. They are traditionally sown on All Souls Day on 2 November but milder autumns now cause too rapid germination and extension growth. Sowing is best now delayed until well into December. Juicy young broad bean seedlings offer pigeons a tasty winter snack, consequently protection with cloches or netting is vital insurance.

From late February onwards dwarf cultivars such as The Sutton or the more vigorous longer podded Meteor Vroma are used. Early cropping is promoted by growing the first batches of seedlings under protection in a glasshouse. Germinate the seed in propagating compost and grow the resultant seedlings until they have formed three to four prominent leaflets. Plant out into fertile, well-cultivated soil and protect with string or netting frameworks supported with bamboo canes to discourage bird damage.

Young broad bean plants supported by string and bamboo canes

More supporting layers will be required as the plants grow and mature. Later sowings are made directly into the vegetable garden. As the plants begin flowering remove the apical buds and about two to three leaves. This deters invasions by the black bean aphid (Aphis fabae). Winged aphids detect the lighter green of upper foliage of broad beans and navigate towards them!

Allow the pods ample time for swelling and the development of bean seeds of up to 2cm diameter before picking. Beware, however, of over-mature beans since these are flavourless and lack succulence. Broad beans have multiple benefits in the garden and for our diets. They are legumes and hence the roots enter mutually beneficial relationships with nitrogen fixing bacteria. These bacteria are naturally present in most soils. They capture atmospheric nitrogen, converting it into nitrates which the plant utilises for growth. In return, the bacteria gain sources of carbohydrates from photosynthesis.

Broad bean root carrying nodules formed around colonies of nitrogen fixing bacteria

Broad beans are pollinated by bees and other beneficial insects. They are good sources of pollen and nectar, encouraging biodiversity in the garden. Nutritionally, beans are high in protein, fibre, folate, Vitamin B and minerals such as manganese, phosphorus, magnesium and iron, therefore cultivating healthy living. Finally, they form extensive roots, improving soil structure, drainage and reserves of organic nitrogen. Truly gardeners’ friends!

Professor Geoff Dixon, author of Garden practices and their science (ISBN 978-1-138-20906-0) published by Routledge 2019.

The Organisation for Economic Cooperation and Development (OECD) defines the Blue Economy as ‘all economic sectors that have a direct or indirect link to the oceans, such as marine energy, coastal tourism and marine biotechnology.’ Other organisations have their own definitions, but they all stress the economic and environmental importance of seas and oceans.

Header image: Our oceans are of economic and environmental importance

To this end there are a growing number of initiatives focused on not only protecting the world’s seas but promoting economic growth. At the start of 2021 the Asian Development Bank (ADB) and the European Investment Bank (EIB) joined forces to support clean and sustainable ocean initiatives in the Asia-Pacific region, and ultimately contribute to achieving Sustainable Development Goals and the climate goals of the Paris Agreement.

Both institutions will finance activities aimed at promoting cleaner oceans ‘through the reduction of land-based plastics and other pollutants discharged into the ocean,’ as well as projects which improve the sustainability of all socioeconomic activities that take place in oceans, or that use ocean-based resources.

ADB Vice-President for Knowledge Management and Sustainable Development, Bambang Susantono, said ‘Healthy oceans are critical to life across Asia and the Pacific, providing food security and climate resilience for hundreds of millions of people. This Memorandum of Understanding between the ADB and EIB will launch a framework for cooperation on clean and sustainable oceans, helping us expand our pipeline of ocean projects in the region and widen their impacts’.

The blue economy is linked to green recovery

In the European Union the blue economy is strongly linked to the bloc’s green recovery initiatives. The EU Blue Economy Report, released during June 2020, indicated that the ‘EU blue economy is in good health.’ With five million people working in the blue economy sector during 2018, an increase of 11.6% on the previous year, ‘the blue economy as a whole presents a huge potential in terms of its contribution to a green recovery,’ the EU noted. As the report was launched, Mariya Gabriel, Commissioner for Innovation, Research, Culture, Education and Youth, responsible for the Joint Research Committee said; ‘We will make sure that research, innovation and education contribute to the transition towards a European Blue Economy.’

The impact of plastics in oceans is well known and many global initiatives are actively tackling the problem. At the end of 2020 the World Economic Forum and Vietnam announced a partnership to tackle plastic pollution and marine plastic debris. The initiative aims to help Vietnam ‘dramatically reduce its flow of plastic waste into the ocean and eliminate single-use plastics from coastal tourist destinations and protected areas.’ Meanwhile young people from across Africa were congratulated for taking leadership roles in their communities as part of the Tide Turners Plastic Challenge. Participants in the challenge have raised awareness of the impact of plastic pollution in general.

But it isn’t just the health of our oceans that governments and scientists are looking at. There is growing interest in the minerals and ore that could potentially be extracted via sea-bed mining. The European Commission says that the quantity of minerals occupying the ocean floor is potentially large, and while the sector is small, the activity has been identified as having the potential to generate sustainable growth and jobs for future generations. But adding a note of caution, the Commission says, ‘Our lack of knowledge of the deep-sea environment necessitates a careful approach.’ Work aimed at shedding light on the benefits, drawbacks and knowledge gaps associated with this type of mining is being undertaken.

With the push for cleaner energy and the use of batteries, demand for cobalt will rise, and the sea-bed looks to have a ready supply of the element. But, the World Economic Forum points out that the ethical dimensions of deep-sea cobalt have the potential to become contentious and pose legal and reputational risks for mining companies and those using cobalt sourced from the sea-bed.

Energy will continue to be harnessed from the sea.

But apart from its minerals, the ocean’s ability to supply energy will continue to be harnessed through avenues such as tidal and wind energy. During the final quarter of 2020, the UK Hydrographic Office launched an Admiralty Marine Innovation Programme. Led by the UK Hydrographic Office, the programme gives innovators and start-ups a chance to develop new solutions that solve some of the world’s most pressing challenges as related to our oceans.

The UK’s Blue Economy is estimated to be worth £3.2 trillion by the year 2030. Marine geospatial data will be important in supporting this growth by enabling the identification of new areas for tidal and wind energy generation, supporting safe navigation for larger autonomous ships, which will play a vital role in mitigating climate change, and more.

The world’s biggest ever survey of public opinion on climate change was published on 27th January, covering 50 countries with over half of the world’s population, by the United Nations Development Programme (UNDP) and the University of Oxford. Of the respondents, 64% believe climate change is a global emergency, despite the ongoing Covid-19 pandemic, and sought broader action to combat it. Earlier in the month, US President Joe Biden reaffirmed the country's commitment to the Paris Agreement on Climate Change.

It is possible that the momentum, combined with the difficulties many countries currently face, may make many look again to geoengineering as an approach. Is it likely that large scale engineering techniques could mitigate the damage of carbon emissions? And is it safe to do so or could we be exacerbating the problem?

The term has long been controversial, as have many of the suggested techniques. But it would seem that some approaches are gaining more mainstream interest, particularly Carbon Dioxide Removal (CDR) and Solar Radiation Modification (SRM), which the 2018 Intergovernmental Panel on Climate Change (IPCC) report for the UN suggested were worth further investigation (significantly, it did not use the term "geoengineering" and distinguished these two methods from others).

One of the most covered CDR techniques is Carbon Capture and Storage (CCS) or Carbon Capture, Utilisation, and Storage (CCUS), the process of capturing waste carbon dioxide, usually from carbon intensive industries, and storing (or first re-using) it so it will not enter the atmosphere. Since 2017, after a period of declining investment, more than 30 new integrated CCUS facilities have been announced. However, there is concern among many that it will encourage further carbon emissions when the goal should be to reduce and use CCS to buy time to do so.

CDR techniques that utilise existing natural processes of natural repair, such as reforestation, agricultural practices that absorb carbon in soils, and ocean fertilisation are areas that many feel could and should be pursued on a large scale and would come with ecological and biodiversity benefits, as well as fostering a different, more beneficial relationship with local environments.

A controversial iron compound deposition approach has been trialled to boost salmon numbers and biodiversity in the Pacific Ocean.

The ocean is a mostly untapped area with huge potential and iron fertilisation is one very promising area. The controversial Haida Salmon Corporation trial in 2012 is perhaps the most well-known example and brings together a lot of the pros and cons frequently discussed in geoengineering — in many ways, we can see it as a microcosm of the bigger issue.

The trial deposited 120 tonnes of iron compound in the migration routes of pink and sockeye salmon in the Pacific Ocean 300k west of Haida Gwaii over a period of 30 days, which resulted in a 35,000km2, several month long phytoplankton bloom that was confirmed by NASA satellite imagery. That phytoplankton bloom fed the local salmon population, revitalising it — the following year, the number of salmon caught in the northeast Pacific went from 50 million to 226 million. The local economy benefited, as did the biodiversity of the area, and the increased iron in the sea captured carbon (as did the biomass of fish, for their lifetimes).

Small but mighty, phytoplankton are the laborers of the ocean. They serve as the base of the food web.

But Environment Canada believes the corporation violated national environmental laws by depositing iron without a permit. Much of the fear around geoengineering is how much might be possible by rogue states or even rogue individuals, taking large scale action with global consequences without global consent.

The conversation around SRM has many similarities — who decides that the pros are worth the cons, when the people most likely to suffer the negative effects, with or without action, are already the most vulnerable? This is a concern of some of the leading experts in the field. Professor David Keith, an expert in the field, has publicly spoken about his concern around climate change and inequality, adding after the latest study that, "the poorest people tend to suffer most from climate change because they’re the most vulnerable. Reducing extreme weather benefits the most vulnerable the most. The only reason I’m interested in this is because of that."

But he doesn't believe anywhere near sufficient research has been done into the viability of the approach or the possible consequences and cautions that there is a need for "an adequate governance system in place".

There is no doubt that the research in this field is exciting but there are serious ethical and governance problems to be dealt with before it can be considered a serious component of an emissions reduction strategy.

Gardens and parks provide visual evidence of climate change. Regular observation shows us that our flowering bulbous plants are emerging, growing and flowering. Great Britain is particularly rich in long term recordings of dates of budbreak, growth and flowering of trees, shrubs and perennial herbaceous plants. Until recently, this was dismissed as ‘stamp collecting by Victorian ladies and clerics’.

The science of phenology now provides vital evidence that quantifies the scale and rapidity of climate change. Serious scientific evidence of the impact of climate change comes, for example, from an analysis of 29,500 phenological datasets. This research shows that plants and animals are responding consistently to temperature change with earlier blooming, leaf unfurling, flowering and migration. This scale of change has not been seen on Earth for the past three quarters of a million years. And this time it is happening with increased rapidity and is caused by the activities of a single species – US – humans!

Iris unguicularis (stylosa). 

Changing seasonal cycles seriously affects our gardens. Fruit trees bloom earlier than previously and are potentially out of synchrony with pollinators. That results in irregular, poor fruit set and low yields. Climate change is causing increased variability in weather events. This is particularly damaging when short, very sharp periods of freezing weather coincide with precious bud bursts and shoot growth. Many early flowering trees and shrubs are incapable of replacing damaged buds, as a result a whole season’s worth of growth is lost. Damaged buds and shoots are more easily invaded by fungi which cause diseases such as dieback and rotting. Eventually valuable feature plants fail, damaging the garden’s benefits for enjoyment and relaxation. 

Plant diseases caused by fungi and bacteria benefit from our increasingly milder, damper winters. Previously, cooling temperatures in the autumn and winter frosts prevented these microbes from over-wintering. Now they are surviving and thriving in the warmer conditions. This is especially the case with soil borne microbes such as those which cause clubroot of brassicas and white rot, which affects a wide range of garden crops.

Hazel (Coryllus spp.) typical wind-pollinated yellow male catkins, which produce pollen.

Can gardeners help mitigate climate change? Of course! Grow flowering plants which are bee friendly; minimise using chemical controls; ban bonfires – which are excellent sources of CO2; establish wildlife-friendly areas filled with native plants and pieces of rotting wood, and it is amazing how quickly beneficial insects, slow worms and voles will populate your garden.

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Professor Geoff Dixon is the author of Garden Practices and their Science, published by Routledge 2019.