Let’s face it: we live in a plastics world. Plastic pollution is doubtless a major societal challenge that raises serious questions about the sustainability of modern consumption patterns. The increasing amount of plastic waste generated each year, dominated by single-use plastics, has created an ecological and waste management crisis. Yet in difficulty often lies opportunity, and throughout history humankind has demonstrated its ability to overcome challenges with ingenuity. In the context of plastic pollution, recognising the ripple effects of a fossil-based economy – conventional plastics are traditionally made from crude oil – alternatives materials loosely referred to as bioplastics, have emerged on the market. But ‘bio’ doesn’t necessarily mean more sustainable and any material substitution must be carefully assessed. My PhD aims to assess the sustainability of these novel bioplastics to ensure they contribute towards tackling the plastics issue, rather than exacerbate it.
So far, my research has addressed the conflicts that emerge as we shift from conventional to bioplastics, while uncovering some of the opportunities too. Life-cycle thinking is at the core of my approach, which helps me look at the issue more holistically. For example, bioplastics are often biodegradable (not all of them are!), which makes them compatible with food waste recycling. However, this potential can only be fulfilled with an adequate and coordinated waste collection system. My latest findings highlighted the concerns over the suitability of biodegradable plastics in food waste treatment strategies, calling for increased collaboration between industry, academia and policy.
Working in a topical and highly mediatised research area is both a blessing and a curse. People immediately connect with the issue of plastic pollution, and tend to show genuine interest in the outputs of my work. However, it also means being acutely aware of all the false promises, misleading claims and unintentionally detrimental effects of public shunning of plastics. Ultimately, we need to recognise that achieving sustainability requires a systems-thinking approach. As Albert Einstein put it: “We cannot solve our problems with the same thinking we used to create them”. In practice, this will mean redesigning our linear consumption model, rather that retrofitting the system at the very end.
The infographic below covers some of the concepts explored here, in common parlance. Thinking about the big picture, my research aims to fulfill the ambitions of a circular economy, which is essentially about keeping materials and products inside the loop for a long as possible.
Around 86% of all global fire events occur in savannas. These fire events contribute to 10% of total annual carbon emissions. African savannas make up most (71%) of the total contribution of savannas to carbon emissions. Humans and savannas have co-existed, and co-evolved, for the last 400,000 years. However, long-term patterns in fire events – known as fire regimes – are changing due to human activity. Current fire regimes in East African savannas, and the new wildfire patterns that are emerging because of them, are complicated by four challenges: 1) the social construction of savanna ecosystems, 2) recent colonial history and persisting neocolonial influence, 3) population growth and urban expansion, and 4) the global environmental agenda.
In this blog I will outline these four challenges in the context of East African savannas and explain how my research contributes to the sustainable management of savanna fires.
A ‘Natural’ Narrative?
Evidence reveals the habitual use of fire by early humans across African savannas dating back to ~400,000 years ago (Bird and Cali, 1998). Fires have an ancient geological history on earth and have influenced global biogeochemical cycles and evolution independent of humans for millennia. However, elemental carbon studies have inferred that fire incidences in sub-Saharan Africa were low until this time, suggesting that humans have exercised significant control over savanna structure and fire regimes for centuries (Bird and Cali, 1998; Bowman et al. 2011). The co-evolution of humans and savannas makes it difficult, and perhaps impossible, to distinguish between natural and anthropogenic fire regimes (Reid, 2012; Laris and Jacobs, 2021).
Fire scientists have recognised a global shift in fire dynamics, a concept termed a ‘pyric transition’, whereby humans have fundamentally altered the two main conditions fires depend upon: geophysical dynamics, such as temperature and relative humidity, and vegetation (Bowman et al. 2013). Fires require living biomass to exist in the landscape (Sa et al. 2011) and human activity causes a departure from ‘natural’ background levels of fire activity by actively manipulating vegetation and soil, such as through agricultural practices, land use change (e.g., deforestation), ignition patterns (e.g., seasonality), and land management- and fire-related policies (e.g., active suppression).
In recent history, human-driven climate change and the transformation of ecosystems globally have resulted in a shift in human influence over the geophysical, as well as the vegetational conditions wildfires synthesise (Bowman et al. 2011), altering conditions above recorded natural variability levels (Jones et al. 2020). Jolly et al. (2015) show that fire seasons, defined by fire-prone weather conditions, lengthened across 25.3% of Earth’s vegetated surface between 1979 and 2013. This resulted in an 18.7% mean increase in the global fire season duration, with some regions, such as East Africa experiencing wildfire seasons more than a month longer than they were in the 1980s. This trend is predicted to accelerate due to this recorded extension having caused an 108.1% increase in burnable vegetated area. The interrelated environmental, social, economic, political, legal, and institutional systems that contextualise and precipitate current and future projected wildfires are, thus, inherently distinct from geologic past (Pyne, 2020).
Western-centric Fire Suppression Policy
Across Eastern Africa, this pyric transition, can be directly attributed to European colonization which led to adoption of a standardised suppression approach to eradicate fire from the landscape. In the late-nineteenth and early-twentieth century, western conservationists initiated a global movement towards the preservation of wilderness, resulting in the eviction of local and indigenous groups across vast areas of protected savanna ecosystems and a ban on their traditional fire practices. Globally, this has reinforced the wildfire paradox, whereby the exclusion of fire from the landscape has induced larger and more intense fires due to excess fuel accumulation and moisture availability. The intensification of fire conditions has not, however, increased the frequency and intensity of fires; many East African savannas that ecologically depend on fire now experience no fire at all.
Moura et al. (2019) identified three main legacies of colonial fire management on East African savannas. Firstly, widespread tensions and conflicts between governments, authorities, and local and indigenous communities, often resulting in the extradition of the latter and repudiation of their rights. This has been widely recognised as a leading factor in unsustainable and exploitative natural resource management. Secondly, the accumulation of ground fuels and an increase in late dry season (LDS) fires that burn extensively and intensively. LDS fires are often associated with extreme wildfire events (EWEs) that adversely impact both human and natural biotic and abiotic systems, including short- and long-term increases in GHG emissions. And thirdly, accelerating ecosystem degradation due to woody and unpalatable shrub encroachment, causing a decline in vegetation and soil health, widespread biodiversity loss (e.g., affecting the life history traits of species that inhabit East African savannas, such as migratory herds that follow distinct rainfall and nutritional gradients), and therefore, increased inter- and intra-species competition for resources (Archibald, 2016).
My research explores the opportunities for equitable institutions, governance, and policy for addressing wildfire challenges across post-colonial East African savanna ecosystems – where all stakeholders and rights holders are recognised, equably represented, included in the decision-making process, and have access to the opportunities and benefits of implemented measures. Fires have a complex socio-ecological history in East African savannas, where wildfire challenges witnessed today reveal underlying environmental, social, economic, and political conflicts and struggles. To understand how different fire management practices and policies affect the delivery of ecosystem (dis)services across the Greater Serengeti-Mara Ecosystem (Kenya and Tanzania), I am going to create a socio-ecological systems model where each practice and/or policy is modelled under projected future climate-socioeconomic scenarios. Due to the diversity of voices and vested interests existing across this landscape, this model will allow us to explore how current and proposed fire management practices affect socio-ecological systems at multiple stakeholder and spatio-temporal scales. In addition to this, a series of workshops will be carried out with local stakeholders and rights holders to investigate local attitudes, empirical realities, and constructions of fire, and scope of future policy and management.
A cornerstone of the modern society is the freedom and ease of movement. In the UK, transportation accounted for a third of carbon dioxide emissions in 2018, of which over half came from cars and taxis. In order to transition to a zero-pollution society, vehicles must be further optimised to increase fuel economy while simultaneously reducing pollutant emissions, including but not limited to carbon dioxide. Other vehicle emissions, such as nitrogen oxides, play a major role in the air quality within our urban areas and must also be tackled. The solution is multi-faceted and will require continued development of the combustion devices within current and new vehicles to meet both our expectations and the standards set by governments.
My research is part-funded by Toyota, a leading manufacturer of hybrid vehicles, and aims to further optimise the hybrid powertrains in their vehicles. With cutting-edge experimental methods, we can probe the fundamental nature of the combustion of bio-derived fuels and fuel components under extreme conditions. This greater understanding of these novel combustion modes directly translates, through the use of computational models, to more efficient and cleaner vehicle technologies within relatively short time frames.
While extracting reliable and valuable data in order to ensure that the computational models used are accurate may often seem tedious, the direct applicability to current technology is a reminder of the instant impact that my research can have. Toyota produces close to ten million vehicles a year and in 2017 on average they emitted 101.2 grams of carbon dioxide per kilometre driven. Improving these vehicles by as little as 1% would result in over 10 tonnes per kilometre less carbon dioxide emitted. This is the equivalent emission from the average electricity usage of 17.7 households in the UK for a calendar year. The average car in the UK travels about 16,000 km a year. That means this saving is the equivalent of 283,000 houses!
Due to the nature of global economies of scale, the small improvements researchers can make could have a profound impact.
Undoubtedly, 2020 has been a year of unprecedented change. In such times, mental resilience is crucial. Having come from a background with research and development experience, where you may often expect the unexpected, I had naively thought this would not be a personal issue. However, it would be wrong not to say that at times I have felt lost, struggling to stay afloat in the wake of COVID-19. After all, what use is a lab-based student working from home? In such times I have found that it helps to see the bigger picture and understanding the bottom line of my work has been pivotal in addressing this. So here it is.
We as individuals, a collective and a planet are experiencing an increasing number of catastrophes which are, in some part, man-made – whether those be industrial, medical, political or otherwise. More often than not, these issues are derived from a lack of foresight or understanding for the implications of a given action we make. After all, by priding ourselves on going boldly where no one has gone before, can we always be certain of the consequences? This certainly seems to have become the case in the post-industrial era with regards to the processing and handling of material wastes.
As a researcher, my work focusses on only one aspect of the pollution issue – recovering the oily foodstuffs which many of us pour down our drain, referred to as Fat, Oil and Grease, or “FOG”. Unaddressed, such pollution in the UK has already been associated with the formation of major ‘fatberg’ blockages in our sewers – some of which have been found to weight over 100 tonnes, costing £50 million to control and up to £40 million in damages in the UK annually. As populations grow, more foodstuffs are disposed to drains and our sewer system ages, this problem will only become more pressing. However, there is also hope. If handled correctly, new technologies could enable us to remove and reuse oily pollutants for new purposes, for example as biofuels or in new synthetic products. In the future, ideas like this may be at the heart of treating waste as part of a wider circular economy.
Perhaps counterintuitively, with this big picture in mind, I aim to address fat, oil and grease with science at the nanoscale. That is to say with materials whose properties are well defined at sizes more than one thousand times smaller than the width of human hair. This will enable the development of new technological solutions which more heavily leverage the behaviour of oily pollution for Fat, Oil and Grease separation instead of more typical energy-intensive operations such as manual removal. In doing this, my position within Imperial College London’s Transition to Zero Pollution Cohort (and more widely, the Science and Solutions for a Changing Planet Doctoral Training Programme, or “SSCP-DTP”) is instrumental to my research in enabling me to maintain a balance of perspectives from other academics on both the intricate details of my work and the bottom line it addresses. This is no better demonstrated than through the exposure which these groups have afforded me already – allowing me to better understand both the wider issues of man-made pollution and our current solutions, as well as the way in which my own scientific expertise can interface with that of other, unrelated fields.
Written by Emma Hibbett, PhD student at Grantham Institute – Climate Change and Environment & Centre for Environmental Policy
COVID-19 has catapulted air pollution into the political foreground as new evidence is emerging which connects coronavirus fatality to air pollution exposure. In the UK, air pollution is already the largest environmental threat; responsible for 36,000 deaths and 3 million lost working days each year. Although the UK government has taken steps to manage the crisis of pollution, 15 million people still live in areas with pollution levels that exceed WHO guidelines for particulate matter.
How politicians decide to manage air pollution matters; whose voice, knowledge, and experiences are included in policy making process will influence the types of solutions that emerge. In a democratic society, local communities should be able to have their voices heard in decisions which affect their lives. However, in air pollution policy making, some community voices are excluded from this process, resulting in policies which do not always reflect the experiences of local people. Often, the most excluded voices are those of the most vulnerable, who disproportionately experience the health impacts of air pollution. In London, for example, just 2% of the capital’s richest experience NO2 levels which exceed EU limits, compared to almost half of the most deprived communities.
When the stakes are this high, it is crucial that the experiences of all are included into policy making in order to ensure that solutions benefit everybody. Community inclusion in policy making is even more critical in times of crisis, but this is when exclusion is at its worst. During the pandemic, local authorities have rushed to pass emergency measures without consulting communities, resulting in tensions and policies which overlook the experiences of certain communities.
My PhD work examines these critical questions of voice and inclusion in our society. To do this, I explore how different community groups do, or do not, gain access to political decision making, and what resources and relationships help them to influence policy making.
My preliminary results highlight critical tensions in our democracy regarding who gets to speak, and who is heard. COVID has brought these tensions in sharp focus; providing an exemplar case of whose voices and experiences are represented in policy change. If we are to successfully transition towards a zero pollution future, we must prioritise these questions of representation and justice. If not, we will continue to exclude vulnerable communities from solutions which are supposed to build a fairer, healthier, and more just society.
Effective lubrication is an essential aspect in the move towards the electrification of mass transportation and in reaching the goal of becoming a net-zero economy. Around one third of fuel consumption in vehicles is due to frictional losses. Therefore, as the demand for electric vehicles (EVs) increases so does the need for effective lubrication of the engineering components in EVs to ensure their reliability, efficiency and to improve the fuel economy.
Due to the complexity of EVs, both thermal heating and cooling occur. For example, in engines, starting conditions vary widely from the running conditions of the engine, therefore, several lubricant formulations are often required to satisfy the various thermal conditions. At high temperatures the viscosity of the lubricant decreases drastically, leading the lubricant to be less effective. Simply using a thicker lubricant, so that the high temperature viscosity of the lubricant is higher, leads to a reduced low temperature performance of the lubricant. Rather than implementing different lubricants for the different conditions, a single lubricant which can remain sufficiently thick at a range of temperatures is more desirable.
Viscosity modifiers (VMs), which are commonly polymeric, are added to lubricants to reduce the viscosity dependence on temperature of the lubricant. This has allowed the use of lubricant for a larger range of temperatures. However, due to the polymeric nature of VMs, they can exhibit varying responses to severe conditions depending on their architecture and chemistry. Commonly used VMs can be described as either viscosity index improvers (VIIs) or thickeners. Thickeners thicken the lubricant uniformly at all temperatures. VIIs, however, increase the viscosity of the lubricant more at high temperatures and do not greatly affect the low temperature viscosity, which is the desired effect. The chemistry of the polymer greatly affects this response, which in turn affects the effectiveness of the VM. Moreover, various architectures of synthesised VMs affect their performance as well as their lifetime as a VM.
It is clear that a lot is there to be understood about the behaviour of VMs in lubricants under severe conditions. Designing more effective VMs will allow us to greatly improve lubricant formulation as well as reduce CO2 emissions by allowing for the efficiency and durability of engineering components in EVs.
Did you know that the battery in your car is the most recycled item in the world? Its recycling process is considered as a gold standard example for the future circular economy of consumer goods.
The humble Lead Acid Battery (or LAB for short) was invented more than 100 years ago and today it is widely used for starting cars, keeping data centres running and storing renewable electricity. The lead used in these batteries is relatively easy to recover through a smelting process with no loss of quality of the recycled product so it can be used again and again. In fact, the metal in your car battery may have already gone through several incarnations of batteries before getting to you! In Europe and the USA it is estimated that over 95% of batteries are collected and recycled to make new batteries.
But if LAB recycling is so successful, what’s the problem? Firstly, this process has a relatively high carbon footprint of 0.12kg of CO2 per kg of lead recycled. While that doesn’t sound too bad, consider that the world recycles millions of tonnes of lead per day! Secondly, batteries that are recycled improperly cause a pollution that is much worse than CO2.
In many developing nations, car batteries are recycled by hand in small cottage industries, in homemade furnaces, by workers who hack batteries apart with improvised tools for a pittance. These workers are fully aware that the lead in the batteries they break could cost them their life. Nonetheless, they choose to go ahead with this work because they have no other source of income. Used LAB recycling in developing nations was classed by the WHO and the Blacksmith Institute to be the most polluting industry of all, shortening life expectancy significantly for both workers and their families.
It is therefore imperative to solve the pollution problems of lead recycling for these small informal recycling activities in the developing world; both to save our planet and our people. However, it is also important to recognise how many rely on this activity for a living. Restricting it may simply make the problem worse. Instead in this project we propose to introduce a novel chemical technique for the recycling of lead based on a new class of solvent that can be easily synthesised from everyday natural ingredients. The aim would be to develop this process to be as cheap and reliable as possible and to provide this technology directly to the people who need it with the help of local partners and charities. It is hoped that this approach can clean up the pollution from this industry, while keeping that invaluable economic lifeline in place for the world’s most vulnerable communities.
My work is focussed around decarbonising society through the enhanced recovery of waste materials. The UK produces 600,000 tonnes of waste tyres per year and in 2018 over half were exported to developing nations such as India (Source: UN Comtrade), where they are burnt in brick kilns or converted to oil in systems with negligible environmental and safety standards.
I am working on developing pyrolysis (heating in the absence of oxygen) as an upcoming waste-recovery technique for these tyres. Pyrolysis can be used to treat any organic waste material, such as biomass, plastics and rubber, to produce a mixture of solid (char), liquid (pyro-oil) and gas (syngas) products. The liquid and gas can be combusted for energy recovery or converted into recycled chemicals. Recycling mechanisms for the solid pyrolysis char product are still developing. I work on developing this pyro-char into activated carbon, a material used to filter air and water.
In my lifetime, atmospheric CO2 has risen by 15%. Abatement of further CO2 emissions to prevent catastrophic climate change is the biggest challenge facing humankind. My PhD focusses on utilising this recycled pyro-char derived activated carbon as a CO2 adsorbent, which can be attached to the end of a fossil fuelled power plant, cement kiln or factory that uses industrial heat to capture the CO2 through a carbon-capture mechanism. This system would prevent the release of CO2 into the atmosphere. Preliminary experiments have shown the potential to capture CO2 quantities of over 10% of the weight of the carbon reversibly and rapidly.
I am working closely with my PhD sponsor, Pyrenergy, to develop pyrolysis as an effective recovery process for waste tyres. Much of the pyro-char feedstock for my PhD is a product of the Pyrenergy industrial process. Tyres are an especially challenging waste material due to the a) heterogeneity between brands and parts of a tyre, b) complex chemistry of rubber, c) high energy of production, and d) their abundance (>2 billion tyres are produced every year). I am working to contribute to the improved recovery of this important resource, which would support circular economy principles whilst reducing waste (tyre) and atmospheric (CO2) pollution to the environment.
Electric vehicles (EVs) are key to achieving a carbon neutral and pollution free society. Transportation makes up a significant proportion of the global carbon footprint; one of the quickest and easiest way to greatly reduce that footprint is through the mass adoption of EVs, replacing all the fossil-fuel-powered vehicles on the road.
The most important component in any EV is the battery pack. Primarily powered by several lithium ion cells, EVs need long driving ranges, fast charging, and long warranties to compete with their fossil-fuel powered counterparts. This requires high capacity battery packs that are efficiently cooled and optimised for weight and cell lifetime.
Unlike a petrol fuel tank, batteries age over time; the more they are used, and the more time that passes, the more their performance deteriorates. They store less charge, become more inefficient and deliver less peak power. For EVs this means that the maximum range and power are always reducing. Slowing the rate of this ageing, therefore, is a key component in improving EVs.
There are many factors that affect the rate of ageing such as current and the amount of charge in the battery. One of the biggest factors is temperature, extreme temperature both hot and cold have negative effects on battery life.
Keeping them cool
The key problem with fast charging is keeping the battery pack within a safe operating temperature. The battery pack generates a lot of heat while fast charging and this heat needs to be removed efficiently to keep all the cells at a safe and uniform temperature. Battery packs need to be cooled uniformly, as if you have one side of you pack in an optimal range but the other getting very hot, the hot side will age faster than the cold side. This can lead to premature failure of the entire pack.
Cell Cooling Coefficient
The Cell Cooling Coefficient (CCC) is a new universal measurement metric for characterising how efficiently a cell can be cooled. It tells you the temperature difference that will occur in a cell when a specified amount of heat is removed from it. My research involves developing this metric for cylindrical cells. Carefully designed rigs are used to experimentally measure the CCC of cylindrical cells of different sizes and under different cooling schemes, such as cooling the base of the cylinder or the sides. Longer term testing will show which cooling schemes are better at slowing down the ageing rate, coupling this with modelling of the CCC, this work will help identify where the thermal performance of these cells can be improved.
Cell manufacturers can use this metric optimise to their cells and produce the best thermally performing cell. As well as helping pack manufactures to compare a wide range of cells from different manufacturers, they will also be able to pick the best cell based on thermal performance for their cooling system. Ultimately, this will help develop battery packs that can be charged faster and which last longer. This will help mitigate some of the biggest downsides to electric vehicles and increase their desirability over fossil-fuel-powered vehicles, taking us a step closer to achieving a zero-pollution and carbon neutral planet.
According to a recent UN report, the world’s population is expected to rise from 7.7 billion to 9.7 billion by 2050 and reach 11 billion by 2100. Such an increase in population will inevitably lead to a proportional increase in the demand for food. Producing enough food to satisfy the needs of this growing population (and doing so sustainably) is, therefore, a pressing global challenge.
Currently, staple food production relies heavily on the use of synthetic nitrogen fertilisers. However, considerable amounts of synthetic nitrogen are lost to the environment in the form of nitrate leaching or as ammonia and nitrous oxide emissions, causing air and water pollution across the globe and contributing to global warming.
Interestingly, a few soil-dwelling bacteria have long been known to be capable of converting the nitrogen in the atmosphere into nitrogen fertiliser. Using these bacteria as bio-fertilisers has therefore been proposed as a way to reduce agriculture’s harmful over dependence on synthetic nitrogen fertilisers. Yet, the process for converting atmospheric nitrogen into fertiliser is highly demanding for the bacteria and is likely to result in a severe “fitness cost” (that is, a negative impact on the bacteria’s ability to grow and replicate and therefore its viability as an eco alternative), preventing the potential use of these bacteria as bio-fertilisers in agriculture.
As part of Imperial’s commitment towards a zero-pollution future, our project we will be taking an innovative approach to tackling the bacterial fitness cost associated with synthesising nitrogen fertiliser from the air. Because, to paraphrase Bob Dylan, we think the answer to the question of how to feed the world sustainably might well be “blowing in the wind”.