Wisdom of Generations: Learning from the Hills and Valleys of the Northeast India

A tea garden in Dibrugarh, Assam
A tea garden in Dibrugarh, Assam. Image credit: Nborkakoty at English Wikipedia.

Northeast (NE) India is more than just a region on the map; it is a treasure trove of beautiful
natural landscapes and ecological wealth that plays an essential role in our planet’s health. As
we celebrate World Environment Day 2024 with the theme of restoration, let us highlight the
ecological richness of Assam and the other Northeastern states of India. From the slopes of
Arunachal Pradesh to the lowlands of Assam, the NE region is a biodiversity hotspot, home to
unique species found nowhere else on Earth. The more we explore this ecological richness,
the more we discover the wonders and mysteries it holds, sparking our curiosity and interest.

The scenic landscapes of the NE region exemplify a dynamic and harmonious relationship
between humans and nature. Indigenous communities here have cultivated a profound
repository of traditional ecological knowledge passed down through generations. The Bodos,
Mishings, Karbis, Nyishis, Angamis, Khasis, and many others have developed a deep-rooted
understanding of their natural surroundings through intimate interactions with forests, rivers,
and mountains.

One of the most remarkable aspects of this traditional wisdom is the extensive knowledge of
local plants and their uses. These communities have identified and utilized numerous plant
species for food, medicine, shelter, and rituals, demonstrating a profound understanding of
the ecological roles of each species. For instance, the Bodos have long made use of medicinal
plants like Bhut Jolokia (ghost chili) for their therapeutic properties, contributing to the
preservation of traditional healing practices. This knowledge not only highlights the ecological
and cultural diversity of the region but also supports sustainable development and
conservation efforts.

Beyond plant knowledge, these communities have developed sophisticated ecosystem
management practices. Indigenous forest management practices in NE India have
significantly contributed to maintaining biodiversity hotspots and preserving wildlife habitats.
Traditional agroforestry systems, such as jhum cultivation practiced by the Karbi and Khasi
tribes, have shown resilience to climate variability while supporting local livelihoods. According
to a recent United Nations report, indigenous peoples’ territories encompass about 80% of the
world’s remaining biodiversity, underscoring the importance of their stewardship in
conservation efforts.

The wisdom of the hills and valleys also embodies resilience—a capacity to adapt and thrive
amidst changing circumstances. Indigenous communities have overcome challenges like
floods, droughts, and shifting climates by drawing on their deep ecological knowledge.

Panimur Waterfalls, Dima Hasao

According to the Indian State Forest Report 2021, Assam’s forest cover is around 35% of its
geographical area, highlighting its critical role in biodiversity conservation and carbon
sequestration. However, this forest cover is declining, and the region faces environmental and
climate challenges, including deforestation, riverbank erosion, and climate change impacts.

Preserving and promoting traditional ecological knowledge is crucial in the face of the global
climate crisis. According to UNESCO, indigenous communities’ traditional knowledge
significantly contributes to the sustainable management of natural resources, benefiting both
local communities and global biodiversity. Recognizing, valuing, and supporting these
practices are essential for environmental conservation, cultural identity, and community
resilience.

Celebrating the wisdom of Assam and Northeast India’s hills and valleys on World
Environment Day reminds us of the transformative power of indigenous knowledge.
Integrating their insights into broader restoration efforts can contribute to building a sustainable
future for all. By embracing the wisdom passed down through generations and augmenting it
with contemporary research and statistics, we, the #GenerationRestoration, can pave the way
toward ecological harmony and resilience in the years to come.

Let us change gears to the tea communities of the NE region. Assam also plays a vital role in
India’s tea production, boasting over 312 210 hectares of tea cultivation. These tea plantations
not only fuel the state’s economy but also hold significant cultural and ecological value. Assam
is among the world’s largest tea-producing regions, with an annual production of 500-700
million kilograms (Mkgs) of tea leaves. The tea industry employs a vast workforce and
supports livelihoods throughout the region, contributing significantly to India’s overall tea
production. The tea plantations in Assam are not only unique but also serve as a prime
example of the harmonious blend of agriculture and biodiversity conservation. The lush green
tea bushes are seamlessly intertwined with shade trees, providing a habitat for various birds
and insects. Assam’s tea is globally renowned for its robust flavor and represents a heritage
deeply rooted in the land and its ecosystems. However, climate and environmental changes
threaten these lush industries, impacting the ecological and socio-economic balance in the
region.

View to Guwahati city
View to Guwahati city

The government has launched several key initiatives to promote development, ecological
conservation, and socio-economic growth across the state. Notable initiatives include the
Assam Budget for Sustainable Development, Assam Tea Tribes Welfare Board, Jal Jeevan
Mission (Har Ghar Jal), Assam Arunodoi Scheme, Assam Green Mission, Assam Skill
Development Mission, and Assam Startup. Effective implementation of these programs aims
to address climate change, promote environmental conservation, and improve the overall
quality of life for the people of Assam. However, the success of these programs depends on
thorough execution at the grassroots level.

What unfolds in the remote corners of Assam reverberates across continents. The lessons
gleaned from this region—on biodiversity conservation, traditional knowledge integration, and
community-led resilience—are universal. They inform global discussions on sustainable
development, emphasizing the need for inclusive approaches that prioritize both people and
the planet.

This World Environment Day, let us heed the call of Northeast India—a call to action for
environmental engagement and climate action involving youth, communities, government
agencies, and non-profit organizations. The region’s youth must understand the challenges
facing their environment and take action to safeguard their communities and natural
surroundings amidst infrastructural growth and development for their own and future
generations. Climate mitigation and adaptation strategies tailored to the region’s unique
context are critical, including afforestation, sustainable agriculture, and flood management
solutions. Youth can lead the way in developing context-specific climate adaptation and
environment restoration strategies that respect local cultures and ecosystems. By immersing
themselves in environmental education, research, and activism, young students can amplify
their voices and influence decision-makers at all levels.

Assam and its neighboring states in India stand out as a distinctive and valuable addition to
the mosaic of Earth’s landscapes. They serve as a beacon of hope and possibility in our
collective journey toward planetary stewardship. The region’s unique natural heritage,
combined with its rich cultural and ethnic diversity, makes it an important site for scientific
research and cultural exchange. As we strive to better understand and protect our planet,
regions like Northeast India offer invaluable insights and opportunities for collaboration.

———————–

This blog is written by Dr Jagannath Biswakarma, School of Earth Sciences, University of Bristol, UK. jagannath.biswakarma@bristol.ac.uk.

Jagannath Biswakarma
Jagannath Biswakarma

‘They don’t have enough’ – schools in England are running food banks for families

The peak of the cost-of-living crisis may have passed, but millions of families are struggling to buy enough food to feed their children. Experiencing food insecurity can be deeply damaging for children and negatively affects their achievement at school.

My research, alongside other studies, shows that schools are operating their own food banks and providing charitable food aid to families. This shows how the education system – from early years to secondary schools – is increasingly at the front line in responding to child poverty, food insecurity, and destitution.

At the start of the financial crisis in 2008 there were few food banks in the UK. Now they are in towns and cities across the country. In 2010-11, charity the Trussell Trust operated 35 food bank centres. Now, the charity runs over 1400.

Recent research from the charity the Food Foundation estimates that one in five families with children do not have secure access to food.

After almost a decade and a half of Conservative governments, a significant number of schools are running food banks to support families and children.

I interviewed school staff at 25 schools across England, in towns and cities including Bristol, Liverpool and London. I wanted to understand how and why schools are providing charitable food to families.

The message was clear: schools were running food banks because they were faced with growing poverty and families struggling financially. Parents can’t afford to buy food or pay bills, and turn to schools for help. As one staff member I spoke to said:

They don’t have enough food, they don’t eat typically well because they can’t afford it, and that’s no fault of their own.

Teachers talked about the cost of living crisis and changes to the UK’s benefit system – in particular the replacement of a number of previous benefit allowances with universal credit – as reasons the food banks were necessary. Research has suggested that the switch to universal credit is leaving some families worse off. “It’s less than what they’re on before. And we have that period where you swap [systems] where you haven’t got any money,” one teacher said.

Child receiving school lunch
Some of the children whose families used school food banks did not qualify for free school meals. Africa Studio/Shutterstock

Some of the families supported by school food banks did not qualify for free school meals for their children but were still struggling. Commenting on who made use of the foodbank, one teacher said:

Sometimes it’s the ones who have free school meals and sometimes it’s the next lot up that are working families and just have absolutely no money at all and no-one to support them or help them with that because they just miss it.

The growth of food banks in schools shows how schools are often acting as an emergency service. “The government has dismantled public services over the past decade and schools are the last people standing,” Ann Longfield, former children’s commissioner for England, has recently commented.

A growing problem

The latest research I am working on with colleagues throws the situation facing families and schools into even starker relief. We are currently investigating how many school-based food banks there are in England and the sorts of schools they are located in.

Our new research, which has not yet been published in a peer-reviewed journal, suggests that 21% of primary and secondary schools operate some kind of food bank. We estimate that this amounts to over 4,000 school-based food banks across England.

This would mean that there are now more food banks inside schools than the combined total of food banks operated by charities the Trussell Trust – the UK’s largest food bank operator – and the Independent Food Aid Network.

If schools are now systematically supporting families through charitable food aid, they need guidance, support and funding. Families need well-paid and secure work and a social security system that provides people with both dignity and the financial means to buy essentials, which includes being able to buy food and clothes and heat their homes.

It’s worth remembering that the goal of a well-functioning welfare state should be to prevent poverty and destitution in the first place rather than provide relief for them after the fact.

Plans to dramatically reduce child poverty, food insecurity and inequality must be central to all political parties’ election manifestos.

This blog is written by Dr Will Baker, Senior Lecturer, School of Education, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Our laser technique can tell apart elephant and mammoth ivory – here’s how it may disrupt the ivory trade

In recent years, the global trade in elephant ivory has faced significant restrictions in an effort to protect dwindling elephant populations. Many countries have stringent controls on the trade of elephant ivory. The sale of mammoth ivory, sourced primarily from long-extinct species, however, remains unregulated.

But it’s a significant challenge for customs and law enforcement agencies to distinguish between ivory from extinct mammoths and living elephants. This is a process that is both time-consuming and requires destroying the ivory.

Now our new study, published in PLOS ONE, presents a major breakthrough – using a well known laser technique to tell mammoth and elephant ivory apart.

Our results couldn’t come soon enough. The number of African elephants has dramatically declined from approximately 12 million a century ago to about 400,000 today.

Annually, over 20,000 elephants are poached for ivory, primarily in Africa. This decline not only disrupts ecological balance, but also diminishes biodiversity. Ultimately, it highlights the urgent need for conservation efforts to protect these species.

The hunt for mammoth ivory is also a problem. The new regulations are leading to a rise in the modern-day “mammoth hunter”. These are people who deliberately set out to excavate mammoth remains from the Siberian permafrost in the summer months.

Driven by the lucrative market for mammoth ivory, these hunters undertake expeditions in remote Arctic regions, where permafrost melting is accelerated by climate change. This has made previously inaccessible mammoth tusks more reachable.

Mammoth fossils being unearthed.
Mammoth fossils being unearthed. Malachi Jacobs/Shutterstock

This activity not only has commercial implications. It also raises significant ethical and environmental concerns. That’s because it disturbs preserved ecosystems and involves the extraction of resources that have great value to paleontological science.

Laser insights

Our study from the University of Bristol, in collaboration with Lancaster University and the Natural History Museum, introduces a potential game-changer. We use a non-invasive laser technique known as Raman spectroscopy to identify the origin of a piece of ivory.

The method works by analysing the biochemical makeup of the ivory, which consists primarily of mineralised tissue composed of collagen (the flexible organic component) and hydroxyapatite (a hard inorganic mineral, containing calcium).

Raman spectroscopy is a well established technique. It has previously demonstrated applications that range from identifying whisky, studying archeological human bones from the Mary Rose ship, understanding how turkey tendons develop and to even identifying the purity of meat sold by the food industry.

The technique works by directing a laser light onto the ivory sample. The energy from the light is temporarily absorbed by the bonds between molecules in the sample, and then almost instantly re-released. This released light scatters back with more or less energy than the initial laser light sent to the sample.

This carries information about the molecular vibrations within the material – providing a unique pattern of light for each type of ivory. The analysis involves studying the differences between these unique fingerprints.

Our study analysed elephant and mammoth samples provided by the Natural History Museum, London. It demonstrated that not only could the technique distinguish between mammoth and elephant ivory, it could also spot differences in ivory from living elephant species.

In fact, we successfully differentiated between ivory from the extinct woolly mammoth (Mammuthus primigenius) and two species of elephants still walking the Earth today (Loxodonta and Elephas maximus).

Important implications

This method offers several advantages over traditional techniques for ivory analysis. Raman spectroscopy is non-destructive and can be performed quickly. This makes it an ideal tool for customs officials who need to make rapid decisions. Our study was conducted on a benchtop spectrometer (a device which breaks up light by wavelength) within a laboratory. But research suggests cheaper and portable, handheld Raman spectrometers could offer equivalent results.

Further research will be needed to refine the technique and expand the database of ivory signatures. We are working with Worldwide Wildlife Hong Kong and the Foreign and Commonwealth Development Office to develop this technique.

More data will ultimately enhance the accuracy of species identification. It could potentially help us detect even finer distinctions – such as the age of the ivory or specific environmental conditions where the elephants or mammoths lived.

There are also other non-destructive techniques, such as X-Ray fluorescence spectroscopy, which could be used as a complementary method to identify the geographical region from which the ivory was taken.

As this technique becomes more accessible and widely adopted, it may become key in global conservation efforts, helping to prevent the illegal trade of elephant ivory.

This article was written by Dr Rebecca Shepherd, Senior Lecturer in Anatomy, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Environmental keywords: understanding ‘vulnerability’

Fresh morning, new sights 

Interconnected beauty 

Time to scratch below[1] 

A door in Bristol. Photo D. Schmidt
A door in Bristol. Photo D. Schmidt

When do we really give ourselves time to reflect? Deeply. As academics we think a great deal, but how often do we immerse ourselves in our immediate environment and open ourselves to the profound possibilities of interdisciplinary exchange?

A rare opportunity to do just that was offered via a Cabot Institute for the Environment workshop earlier this year. Run in conjunction with the ‘Environmental Keywords’ project team (PI: Dr Paul Merchant, Modern Languages, Co-I: Professor Daniela Schmidt, Earth Sciences and Senior Research Associate: Dr Claire Cox, English Literature), the session sought to unpack how terms commonly-used used in communications on climate change are variously perceived, and what they might be understood to mean.

As academics engaged in urgent environmental challenges, our interdisciplinary communications can too often stall on discipline-specific definitions across, for example, the humanities and hard sciences. Our half-day workshop sought to open a shared space for interdisciplinary exchange by focussing on the word ‘vulnerability’ as a starting point towards co-created understandings that have the potential to catalyse new interdisciplinary collaborations, and, more widely, to inform local policy makers’ thinking.

Environmental Keywords: Phase 1 Community Workshops

The Cabot workshop marked the launch of the second phase of the Environmental Keywords project (also supported by Research England’s Policy Support Fund). The first phase, funded by NERC (Natural Environment Research Council), took place in 2021-22 and comprised a series of three Bristol-based community workshops which explored how a creative facilitation methodology grounded in key terms in environmental research and activism (such as ‘resilience’, ‘justice’ and ‘transitions’) might enhance community engagement with contemporary environmental challenges. These workshops were held across the city with community partner organisations including Heart of BS13 and Eastside Community Trust, and included colleagues from a range of disciplinary backgrounds from the University of Bristol.

Key to the co-creation approach was an introductory ‘Walk and Talk’ activity around the community groups’ localities. Crucially, the walks not only acknowledged the group members’ as leaders and experts on their own terms, but also provided shared points of reference for later round-table discussions. From these free-flowing discussions it became clear that for many of the community participants survival considerations, such as the cost of living and physical safety, were more pressing than, what were perceived as, the distant and abstract threats of climate change.

The Cabot ‘Walk and Talk’

The group walks and talks through Bristol. Photo: D. Schmidt.
The group walks and talks through Bristol. Photo: D. Schmidt.

As Robert Macfarlane observed: ‘walking is not the action by which one arrives at knowledge; it is itself the means of knowing.’[2]. For the Cabot workshop we again employed the walking methodology; and with ‘vulnerability’ in mind, took a route from Royal Fort House to King Square, returning past the Bristol hospitals via Marlborough Street. This gave us ample opportunity to chat, as well as to observe our surroundings, make notes and take photographs of things that exemplified ‘vulnerability’ to us or sparked our interest.

Round table reflections

Emergent themes from the discussion that followed our walk were as insightful as they were wide-ranging. Much of the consideration centred around vulnerabilities arising from poverty and socio-economic disparities locally and globally; and the associated issues of power and power structures, agency, lack of choice and who decides on the choices we have.

Physical vulnerabilities, as prompted by Bristol’s steep topography from sea level to hilltop, were also deliberated, as were ideas about differing perceptions of our own vulnerability, often based on gender, health or age. We noted that people can also refuse to recognize their own vulnerability for many reasons.

As we had walked though Bristol’s Clean Air Zone issues including pollution, policy, public health, equity and political transparency quickly came to the fore. The shifting dynamics between vulnerability and reliance were also discussed, as was loss of the commons and of green spaces globally.
The complexity of the climate crisis was framed in terms of Rob Nixon’s concept of ‘slow violence’ and difficulties of responding to such an incremental set of environmental threats [3]. There was also a sense that as a concerned group of individuals, we need to understand vulnerability in order to achieve social justice; and that interdisciplinarity can open us to new ways of perceiving and understanding the world beyond the limitations of our personal inclinations and disciplinary boundaries.

Saying it with syllables

To round off the session, and as a creative counterpoint to the intensity of the workshop, there was an invitation to describe a ‘moment of delight’ from the walk and to express it in the form of a haiku: an ancient and very short poetic form synonymous with Japan, based on a pattern of syllables over three lines.

Almost immediately another, unexpected, vulnerability was highlighted – that of language. Several of the group’s English-as-an-additional-language speakers encountered issues around thinking ‘poetically’ in another language. Here, writing in one’s birth language came more easily, with the poem then being translated into English. Environmental Keywords’ exploration into the relationship between the words we use and the thoughts we seek to express suddenly became very tangible indeed.

Voy adelante
ciudad nueva, cielo gris
me pierdo – no soy

I walk on
new city, grey skies
I get lost – I am not [4]

[1] Haiku from Cabot workshop.

[2] Robert Macfarlane, The Old Ways (London: Penguin Books Ltd, 2013), p. 27.

[3] Rob Nixon, Slow Violence and the Environmentalism of the Poor (Cambridge, Massachusetts: Harvard University Press, 2011).

[4] Portuguese/English haiku from workshop.

———————————-

This blog is written by Cabot Institute for the Environment member Dr Claire Cox at the University of Bristol.

Haiku has captured the essence of seasons for centuries – new poems contain a trace of climate change

A successful haiku could be described as a half-finished poem. Originating in Japan in the 17th century, the haiku uses a combination of sensory language, seasonal references, a sense of contrast and a focus on the present tense to share an experience between writer and reader.

It relies on the reader to “finish” the poem by employing their recollections of sensations and emotions to connect to the moment described as vividly as they do their own experiences.

Haiku often depict moments in a particular season by describing the behaviour of animals, the weather and the appearance of plants. With a new generation of haiku poets, there’s a whole new collection of work that reflects how seasons are changing as a result of rising global temperatures.

Could haiku poetry written more recently contain a trace of the changes wrought by our warming climate? That’s something one of us (Jasmin) set out to investigate by analysing haiku published in English over the last 30 years.

First, let’s learn how to read haiku.


Do the seasons feel increasingly weird to you? You’re not alone. Climate change is distorting nature’s calendar, causing plants to flower early and animals to emerge at the wrong time.

This article is part of a series, Wild Seasons, on how the seasons are changing – and what they may eventually look like.


What enables this brief poetic form to achieve its resonance is its use of negative space. A haiku is a poem in two parts – a fragment (one line) and a phrase (two lines), divided by a pause (signified by a line break or punctuation).

Related to the concept of ma in Japanese visual arts, which perceives empty space in an artwork as a positive entity, the negative space in haiku is a way in to the contemplative experience of the poem.

The following by Japanese poet Matsuo Basho (1644-94) is the most famous haiku ever composed:

old pond –

a frog leaps in

water’s sound

A frog in a pond surrounded by spawn.
Frogspawn is a harbinger of spring in the UK.
Lesley Andrew/Shutterstock

To write a different account of this same event, you could say something like a frog leapt into an old pond and made a sound. But the key distinction between the two is the negative space that follows Basho’s first line. It encourages the reader to pause, breathe and contemplate the old pond before they encounter the frog leaping and the sound of the water.

When our minds become still, and reflective, like the old pond, we witness the action of an animal living simply according to its nature. We perceive things just as they are. The result is an experience of interconnectedness: a realisation that we are not separate from the natural world, but a part of it.

In the following haiku by Basho we experience the season as both a physical setting and as a metaphor for emotional experience:

no-one walks

along this road but I

autumn evening

A tree-lined urban path in the evening.
Autumn’s arrival can be felt in falling leaves and earlier sunsets.
S_Oleg/Shutterstock

In a world of increasing anxiety and distraction, the negative space in a haiku affords us moments of reflection and invites us into a dialogue with the rest of the natural world.

It requires a sensitivity on the part of the reader, but its effect is to instil an appreciation for what surrounds us. Through a meaningful, felt awareness of the seasonal cycles, the reading and writing of haiku inspires a deeper connection to our environment.

How haiku is changing

I spent the summer of 2022 in my home office, consuming decades of haiku journals and anthologies, trying not to leave sweaty fingerprints on their ancient covers in the unnatural 40°C heat. As that year’s researcher-in-residence for the British Haiku Society, working on a project called Twisting Point, I was searching for tell-tale traces of climate change in the English-language haiku archives.

My goal was to contrast present-day haiku against older archival ones, using the differences between them to make readers sensitive to nature’s decline and to suggest how the English-language haiku form might be evolving due to climate change.

I was looking at 30 years’ worth of haiku. In the UK during this time flying insect populations have fallen by over 60%, 41% of wildlife species have decreased in abundance and the frequency of heatwaves, floods and other extreme weather have all increased. More than enough change has occurred in these three decades to manifest in the archives.

Yet, these changes emerge in a strange fashion. It’s hard to write about nature’s losses, and writers tend to do so unconsciously. Rather than tracking population declines in concrete terms, then, the language used around certain species has altered, becoming soaked in grief.

For example, over 25 years numbers of curlews, a wading bird, have halved in the UK. Earlier haiku described their powerful cry “lengthen[ing] the hill[s]”; a poem written in 2022 found them “calling across wintry mudflats, haunting the wind”. Similarly, since 2000, declining butterflies have moved from being a “cloud” common in the background of haiku to lone survivors “pushing against time”.

A wading bird in shallow water with a long, slender, curved beak.
Curlews use their crescent beaks to probe the soft intertidal mud for worms.
Emutan/Shutterstock

The archetypal seasonal words used in haiku are shifting too, disrupting centuries-long traditions of meaning and emotion. As winter has been squeezed into weeks, spring arrives earlier and frosts become tardier, snowdrops have become a symptom of the changing haiku form.

Here is a haiku published in the 1990s in the spring seasonal category (the traditional haiku date for spring’s beginning is February 4):

song of a greenfinch

a ray of sun on cold steps

and a few snowdrops

By 2022, snowdrops are emerging in December in this tanka (a slightly longer poem variety) by Ruth Parker:

Omicron triumphs

and sends Christmas packing – but in the garden

the delicate white hope

of snowdrops

Small white flowers.
Snowdrops are flowering earlier as the climate warms.
Daniel Chetroni/Shutterstock

I was struck by how few haiku seemed to address climate change. Twisting Point became my call to arms for haiku writers. Haiku are about intense moments of perception, in which “the vast is perceived in one thing”. But in addressing climate change so little, are English-language haiku really depicting “the vast”?

Since 2022 the issue has come to the fore, with The Guardian describing how Japanese haiku writers are “lost for words” in the face of climate change. Meanwhile, Twisting Point is to be republished in a journal of the New Zealand Poetry Society. The call to haiku arms is growing: the vast climate crisis is upon us, and we should write about it.The Conversation

———————-

This blog was written by Jasmin Kirkbride, Lecturer in Publishing, University of East Anglia and Paul Chambers, PhD Candidate in Creative Writing, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

East Africa must prepare for more extreme rainfall during the short rainy season – new study

Rainy season in Kenya

East Africa has recently had an unprecedented series of failed rains. But some rainy seasons are bringing the opposite: huge amounts of rainfall.

In the last few months of 2023, the rainy season known as the “short rains” was much wetter than normal. It brought severe flooding to Kenya, Somalia and Tanzania. In Somalia, more than 2 million people were affected, with over 100 killed and 750,000 displaced from their homes. Tens of thousands of people in northern Kenya lost livestock, farmland and homes.

The very wet short rainy seasons are linked to a climate event known as a positive Indian Ocean Dipole (known as the “IOD”). And climate model projections show an increasing trend of extreme Indian Ocean dipoles.

In a new research paper, we set out to investigate what effect more frequent extreme Indian Ocean Dipole events would have on rainfall in east Africa. We did this using a large number of climate simulations and models.

Our results show that they increase the likelihood of very wet days – therefore making very wet seasons.

This could lead to extreme weather events, even more extreme than the floods of 1997, which led to 10 million people requiring emergency assistance, or those of 2019, when hundreds of thousands were displaced.

We recommend that decision-makers plan for this kind of extreme rainfall, and the resulting devastating floods.

How the Indian Ocean Dipole works

Indian Ocean Dipole events tend to occur in the second half of the year, and can last for months. They have two phases: positive and negative.

Positive events occur when the temperature of the sea surface in the western Indian Ocean is warmer than normal and the temperature in the eastern Indian Ocean is cooler than normal. Put simply, this temperature difference happens when winds move warmer water away from the ocean surface in the eastern region, allowing cooler water to rise.

In the warmer western Indian Ocean, more heated air will rise, along with water vapour. This forms clouds, bringing rain. Meanwhile, the eastern part of the Indian Ocean will be cooler and drier. This is why flooding in east Africa can happen at the same time as bushfires in Australia.

The opposite is true for negative dipole events: drier in the western Indian Ocean and wetter in the east.

Under climate change we’re expecting to see more frequent and more extreme positive dipole events – bigger differences between east and west. This is shown by climate model projections. They are believed to be driven by different paces of warming across the tropical Indian Ocean – with western and northern regions projected to warm faster than eastern parts.

Often heavy rain seasons in east Africa are attributed to El Niño, but recent research has shown that the direct impact of El Niño on east African rainfall is actually relatively modest. El Niño’s principal influence lies in its capacity to bring about positive dipole events. This occurs since El Niño events tend to cool the water in the western Pacific Ocean – around Indonesia – which also helps to cool down the water in the eastern Indian Ocean. These cooler temperatures then help kick-start a positive Indian Ocean Dipole.

Examining unprecedented events

Extreme positive Indian Ocean Dipole events are rare in the recent climate record. So to examine their potential impacts on rainfall extremes, we used a large set of climate simulations. The data allowed us to diagnose the sensitivity of rainfall to larger Indian Ocean Dipole events in a statistically robust way.

Our results show that as positive dipole events become more extreme, more wet days during the short rains season can be expected. This effect was found to be largest for the frequency of extremely wet days. Additionally, we found that as the dipole strength increases, the influence on the most extreme days becomes even larger. This means that dipole events which are even slightly “record-breaking” could lead to unprecedented levels of seasonal rainfall.

Ultimately, if positive Indian Ocean Dipole seasons increase in frequency, as predicted, regular seasons of flooding impacts will become a new normal.

One aspect not included in our analysis is the influence of a warmer atmosphere on rainfall extremes. A warmer atmosphere holds more moisture, allowing for the development of more intense rain storms. This effect could combine with the influence of extreme positive dipoles to bring unprecedented levels of rainfall to the Horn of Africa.

2023 was a year of record-breaking temperatures driven both by El Niño and global warming. We might expect that this warmer air could have intensified rain storms during the season. Indeed, evidence from a recent assessment suggests that climate change-driven warming is highly likely responsible for increased rainfall totals.

Responding to an unprecedented future

Policymakers need to plan for this.

In the long term it is crucial to ensure that any new infrastructure is robust to withstand more frequent and heavier rains, and that government, development and humanitarian actors have the capacity to respond to the challenges.

Better use of technology, such as innovations in disseminating satellite rainfall monitoring via mobile phones, can communicate immediate risk. New frontiers in AI-based weather prediction could improve the ability to anticipate localised rain storms, including initiatives focusing on eastern Africa specifically.

Linking rainfall information with hydrological models designed for dryland environments is also essential. These will help to translate weather forecasts into impact forecasts, such as identifying risks of flash flooding down normally dry channels or bank overflow of key rivers in drylands.

These technological improvements are crucial. But better use of the forecast information we already have can also make a big difference. For instance, initiatives like “forecast-based financing”, pioneered by the Red Cross Red Crescent movement, link forecast triggers to pre-approved financing and predefined action plans, helping communities protect themselves before hazards have even started.

For these endeavours to succeed, there must be dialogue between the science and practitioner communities. The scientific community can work with practitioners to integrate key insights into decisions, while practitioners can help to ensure research efforts target critical needs. With this, we can effectively build resilience to natural hazards and resist the increasing risks of our changing climate.The Conversation

———————————

This blog is written by David MacLeod, Lecturer in Climate Risk, Cardiff University; Erik W. Kolstad, Research professor, Uni Research; Cabot Institute for the Environment member Katerina Michaelides, Professor of Dryland Hydrology, School of Geographical Sciences, University of Bristol, and Michael Singer, Professor of Hydrology and Geomorphology, Cardiff University. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Dune: what the climate of Arrakis can tell us about the hunt for habitable exoplanets

Frank Herbert’s Dune is epic sci-fi storytelling with an environmental message at its heart. The novels and movies are set on the desert planet of Arrakis, which various characters dream of transforming into a greener world – much like some envision for Mars today.

We investigated Arrakis using a climate model, a computer program similar to those used to give weather forecasts. We found the world that Herbert had created, well before climate models even existed, was remarkably accurate – and would be habitable, if not hospitable.

However, Arrakis wasn’t always a desert. In Dune lore, 91% of the planet was once covered by oceans, until some ancient catastrophe led to its desertification. What water remained was further removed by sand trout, an invasive species brought to Arrakis. These proliferated and carried liquid into cavities deep underground, leading to the planet becoming more and more arid.

To see what a large ocean would mean for the planet’s climate and habitability, we have now used the same climate model – putting in an ocean while changing no other factors.

When most of Arrakis is flooded, we calculate that the global average temperature would be reduced by 4°C. This is mostly because oceans add moisture to the atmosphere, which leads to more snow and certain types of cloud, both of which reflect the sun’s energy back into space. But it’s also because oceans on Earth and (we assume) on Arrakis emit “halogens” that cool the planet by depleting ozone, a potent greenhouse gas which Arrakis would have significantly more of than Earth.

Map of Arrakis
The authors gathered information from the books and the Dune Encyclopedia to build their original model. Then they added an ocean with 1,000 metres average depth.
Farnsworth et al, CC BY-SA

Unsurprisingly, the ocean world is a whopping 86 times wetter, as so much water evaporates from the oceans. This means plants can grow as water is no longer a finite resource, as it is on desert Arrakis.

A wetter world would be more stable

Oceans also reduce temperature extremes, as water heats and cools more slowly than land. (This is one reason Britain, surrounded by oceans, has relatively mild winters and summers, while places far inland tend to be hotter in summer and very cold in winter). The climate of an ocean planet is therefore more stable than a desert world.

In desert Arrakis, temperatures would reach 70°C or more, while in its ocean state, we put the highest recorded temperatures at about 45°C. That means the ocean Arrakis would be liveable even in summer. Forests and arable crops could grow outside of the (still cold and snowy) poles.

There is one downside, however. Tropical regions would be buffeted by large cyclones since the huge, warm oceans would contain lots of the energy and moisture required to drive hurricanes.

The search for habitable planets

All this isn’t an entirely abstract exercise, as scientists searching for habitable “exoplanets” in distant galaxies are looking for these sorts of things too. At the moment, we can only detect such planets using huge telescopes in space to search for those that are similar to Earth in size, temperature, available energy, ability to host water, and other factors.

Scatter chart of planets comparing habitability and similarity to Earth.
Both desert and ocean Arrakis are considerably more habitable than any other planet we have discovered.
Farnsworth et al, CC BY-SA

We know that desert worlds are probably more common than Earth-like planets in the universe. Planets with potentially life-sustaining oceans will usually be found in the so-called “Goldilocks zone”: far enough from the Sun to avoid being too hot (so further away than boiling hot Venus), but close enough to avoid everything being frozen (so nearer than Jupiter’s icy moon Ganymede).

Research has found this habitable zone is particularly small for planets with large oceans. Their water is at risk of either completely freezing, therefore making the planet even colder, or of evaporating as part of a runaway greenhouse effect in which a layer of water vapour prevents heat from escaping and the planet gets hotter and hotter.

The habitable zone is therefore much larger for desert planets, since at the outer edge they will have less snow and ice cover and will absorb more of their sun’s heat, while at the inner edge there is less water vapour and so less risk of a runaway greenhouse effect.

It’s also important to note that, though distance from their local star can give a general average temperature for a planet, such an average can be misleading. For instance, both desert and ocean Arrakis have a habitable average temperature, but the day-to-day temperature extremes on the ocean planet are much more hospitable.

Currently, even the most powerful telescopes cannot sense temperatures at this detail. They also cannot see in detail how the continents are arranged on distant planets. This again could mean the averages are misleading. For instance, while the ocean Arrakis we modelled would be very habitable, most of the land is in the polar regions which are under snow year-round – so the actual amount of inhabitable land is much less.

Such considerations could be important in our own far-future, when the Earth is projected to form a supercontinent centred on the equator. That continent would make the planet far too hot for mammals and other life to survive, potentially leading to mass extinction.

If the most likely liveable planets in the universe are deserts, they may well be very extreme environments that require significant technological solutions and resources to enable life – desert worlds will probably not have an oxygen-rich atmosphere, for instance.

But that won’t stop humans from trying. For instance, Elon Musk and SpaceX have grand ambitions to create a colony on our closest desert world, Mars. But the many challenges they will face only emphasises how important our own Earth is as the cradle of civilisation – especially as ocean-rich worlds may not be as plentiful as we’d hope. If humans eventually colonise other worlds, they’re likely to have to deal with many of the same problems as the characters in Dune.The Conversation

————————

This blog is written by Cabot Institute for the Environment members Dr Alex Farnsworth, Senior Research Associate in Meteorology, and Sebastian Steinig, Research Associate in Paleoclimate Modelling, University of Bristol; and Michael Farnsworth, Research Lead Future Electrical Machines Manufacturing Hub, University of Sheffield. This article is republished from The Conversation under a Creative Commons license. Read the original article.

White men dominate the environment sector – here’s how to encourage more diverse voices

Bringing a diversity of people to the table and giving plenty of opportunities for everyone to have their say is key to ensuring real inclusivity. Rawpixel.com/Shutterstock

In early 2021, I observed a meeting of 25 people working on climate change policy in Bristol as part of my research into creating a just and fair climate transition. I was struck by how the conversation was dominated by one group: white men. From that moment, inequality in decision-making became a major part of my climate justice research.

I drew a table in my notebook with four headings: white men, white women, minoritised men and minoritised women. Every time someone spoke, I put a tick in the relevant column. By the end of that meeting, white men had three times as many ticks as the rest combined. I took a picture of the table and sent it to my research partner, Alice Venn.

“Should I keep recording this data?” I asked. Venn approved of this approach, so data on gender and race became central to our study.

We observed various meetings including steering groups, member consultations and board meetings for nine hours over the course of six months. During that time, white men spoke for 64% of the time and represented 40% of participants. A slightly higher percentage (41%) of white women were present in the meetings we observed, but they spoke for just 33% of the time.

By comparison, minoritised women made up 14% of participants in meetings and spoke 2% of the time. Minoritised men made up 5% of participants in meetings and spoke only 1% of the time.

This is no great surprise. The environment sector is notoriously one of the least diverse, with only 3.5% of people working in environmental jobs identifying as being from an ethnic minority. In the environmental charity sector, that figure is 6%. This compares quite starkly with an average across the UK workforce of 15% of employees from racial or ethnic minorities.

Diverse voices and critical discussions are key to making robust, inclusive and future-proof decisions. If a group of people who come from similar backgrounds (whether because of race, class or gender) assess a decision they are making for flaws, they are unlikely to find them because they are likely to agree with one another.

There may then be unexpected pushback against policies such as 15-minute neighbourhoods (where residents can reach all the facilities they need within a 15-minute walk, bike ride or journey on public transport), because groups who do not benefit from those schemes have not been consulted and their dissent has not been anticipated.

In Bristol, our observations of meetings found that participants showed very little critical engagement with existing policies, such as cycling route safety planning that centred around men commuting, or expansion plans for Bristol airport. Often, there was no space or time in meetings to be critical of existing ideas and narratives, or to challenge existing policy processes and systemic problems.

Climate justice was only mentioned in one of the nine meetings we observed. Climate vulnerability was not mentioned at all. Meetings felt very busy, filled with packed agendas, with little opportunity to make radical suggestions for change.

Changing the dynamic

Even with a mix of women and men or representative examples of minoritised people in the room, these people won’t necessarily speak up. Women are less likely to have influence in board meetings and struggle to be heard in online meetings.

A good chair will be aware of these dynamics and take steps to ensure inclusivity, perhaps by setting up small group tasks to build confidence or monitoring who is speaking and calling on quieter people directly.

Another technique, known as the “2-2 method”, involves asking “what are two reasons someone would agree, and two someone would disagree?” before opening the floor for critique. An open workplace culture where people feel they can trust leadership even if they are critical is also important, and will make more open and inclusive meetings easier to conduct.

From observations in our study, women tend to take longer to answer a question, which gives space for men to jump in or interrupt. One of the female participants told us: “I notice men tend to talk over me and interrupt me, a lot.”

Minoritised individuals may be more reticent to speak if they feel they won’t be listened to. Previous research shows that some board members worry they will be tokenised by being asked to represent huge groups – this puts undue pressure on them to be the spokesperson for their race or ethnicity, and does not treat them as an individual with worthy opinions. Being aware of these dynamics and getting it right as an employer or community leader is key to making change and ensuring everyone feels able to speak up.

A diversity redesign

As a follow-up from our study, we are training members of the environment sector in Bristol. We have been working with the UK-wide, equalities-led social enterprise The Diversity Trust and video production company Beeston Media to provide a series of workshops and videos about making more inclusive decisions, creating an open workplace culture, and recruiting and retaining diverse staff.

So far we’ve held three workshops, each attended by more than 25 people from a wide range of sectors and organisations. Three more workshops are planned for spring and summer 2024.

As a result, the Bristol Advisory Committee on Climate Change has already changed its recruitment policies. The committee has widened its definition of an expert, moving away from a research-based definition and explicitly noting that lived experience and community knowledge can be accepted as expertise.

Meeting space policies have also been redesigned at several organisations – for example, by implementing the 2-2 method and ensuring that chairs avoid tokenism and use micro-affirmations to build confidence.

We are monitoring the impact of these changes with one-to-one support calls, surveys and peer-to-peer support groups. One testimony stated that “the training you have been running has been so valuable in helping environmental organisations to develop better equality, diversity and inclusion practice”.

Improvements to embrace a more diverse and inclusive environmental sector are critical to ensuring a greener, fairer and more sustainable future for all. But this transition needs to be designed with people, rather than imposed on them. The shift can begin in a boardroom, steering group, or committee meeting. Any institution that pays attention to how it makes decisions, and who is consulted, will help to ensure the green transition is as inclusive as possible.

————————–

This blog is written by Dr Alix Dietzel, Senior Lecturer in Climate Justice, and Associate Director of Impact at the Cabot Institute for the Environment. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Dr Alix Dietzel
Dr Alix Dietzel

Vaccinating livestock against common diseases is a form of direct climate action

PERO studio/Shutterstock

Animal diseases have a devastating impact on livestock production. In 2022, for example, 131 million domestic poultry died or were culled as a result of avian influenza (also called “bird flu”).

Yet the cost of livestock disease goes beyond a shortage of turkeys for the holiday season. Every animal that is lost to a preventable disease is also associated with greenhouse gas emissions that the planet cannot afford.

Animal diseases reduce the productivity of a farm. This is because livestock grow at a slower pace, are unable to reach target weights or fail to reproduce. Diseases may also drastically increase the rate at which livestock die.

Diseases with high mortality levels, such as classical swine fever or avian influenza, mean farmers need to use more resources and raise additional animals to maintain food production. This will cause the generation of more greenhouse gas emissions.

However, controlling common animal diseases effectively through tools like vaccination proves to be a sustainable way of tackling climate change. According to new research that was carried out by one of us (Jude Capper), controlling “high pathogenicity” avian influenza – a virus that can cause severe disease and death in infected poultry – with vaccines would reduce greenhouse gas emissions by almost 16% per kilogram of meat without having to resort to culling.

A vet removing the carcasses of chickens on a farm that have died from bird flu.
Bird flu caused the death of 131 million domestic poultry in 2022.
Pordee_Aomboon/Shutterstock

Reducing emissions

Using vaccines to prevent disease also supports better food security and livelihoods. Porcine reproductive and respiratory syndrome is endemic in countries including the US, China and Vietnam. The virus does not always kill infected pigs, but it limits output from swine farms as it affects reproduction and growth. In affected herds, up to 19% of sows fail to produce piglets and 75% of young pigs die before weaning.

Every 100,000 sows spared from porcine reproductive and respiratory syndrome would prevent more than 420,000 tonnes of greenhouse gas emissions. This is equivalent to removing more than 230,000 cars from the road, and means greenhouse gas emissions per kilogram of pork would fall by 22.5%.

Similarly, eliminating foot and mouth disease where it is endemic (many low- and middle-income countries in Africa and Asia) would cut emissions by more than 10% per kilogram of product. Foot and mouth disease is highly contagious and led to a crisis for UK agriculture when it hit in 2001. The disease is a major cause of reduced production around the globe, despite not always killing livestock.

Traffic on a motorway surrounded by heavy smog.
Vaccinating 100,000 sows against porcine reproductive and respiratory syndrome could reduce emissions by an amount comparable to that produced by 230,000 cars.
testing/Shutterstock

Controlling outbreaks

More than 80% of farms in low-income countries are smallholder or backyard operations. This type of farm generates more greenhouse gas emissions per unit of meat, milk and eggs than commercial farms because of lower productivity.

Farms in these countries are reservoirs of disease. This means the threat of a global outbreak – and the associated implications for greenhouse gas emissions – is never zero. These reservoirs occur because of a lack of disease surveillance, infrastructure, trained personnel and available medicines to detect, record and control livestock diseases.

Nevertheless, controlling endemic livestock diseases through vaccination reduces the risk of outbreaks across species and regional borders. By controlling avian bronchitis (a highly contagious respiratory disease mainly in chickens) where it is endemic among backyard poultry, we can reduce emissions by more than 11% while also limiting the risk of an outbreak.

Outbreaks can undermine global trade, production and food security. Economic analysis of an African swine fever outbreak in China found that low pork supply would increase global pork prices by between 17% and 85%. The findings also suggest that unmet demand would have significant consequences for the affordability of other meats.

Vaccination also helps to address the threat of antimicrobial resistance, which poses a major threat to human health around the world. Research estimates that antimicrobial resistance was associated with around 5 million deaths globally in 2019.

Free range chicken on a poultry farm.
Most farms in low-income countries are smallholder or backyard operations.
goodbishop/Shutterstock

Moving towards sustainability

Our food system is responsible for one-third of global greenhouse gas emissions. Improving animal health would thus make a significant contribution to meeting the IPCC’s challenge of halving emissions by 2030.

At the same time, it would minimise the broader environmental impact of farming through efficiency gains. This is particularly crucial in low-income countries where the inability to control or treat livestock diseases has greater consequences for malnutrition, poverty and human health.

Sustainable food production balances three components: environmental responsibility, economic viability and social acceptability. Using vaccines to reduce livestock disease around the globe is one of the few innovations that improves all three – benefiting animals, people and the planet.

——————————–

This blog is written by David Barrett, Professor of Bovine Medicine, Production and Reproduction, University of Bristol and Jude Capper, Professor of Sustainable Beef and Sheep Production, Harper Adams University. This article is republished from The Conversation under a Creative Commons license. Read the original article.

‘Foul and loathsome’ or jewels of the natural world? The complicated history of human-frog relations

Shutterstock

When was the last time you saw a frog? Perhaps you came across one in your garden and wondered at its little hands, glossy skin and what looked very much like a contented smile.

Maybe you regularly see them on Instagram or TikTok, where “frog accounts” have proliferated in recent years. People share adorable cartoon frogs, coo over crocheted frogs or go gaga for frogs dressed in cute hats.

In fact, our fascination with frogs isn’t new. As our research has found, the history of human-frog relations is long and complicated – and not all of it is nice.

Why we love frogs

There is a rich history of people really loving frogs.

This is interesting, because many people much prefer mammals and birds over reptiles and amphibians.

But the frog is an exception – for a lot of reasons. People tend to be attracted to baby-like faces. Many species of frog have the large eyes characteristic of young animals, humans included.

Having no teeth and no sharp claws, they also do not seem to be immediately threatening, while many of them have beautiful skin colouring and some are improbably tiny.

Frogs are truly among the jewels of the natural world, unlike toads which – with their more mundane colours and “warty skins” – do not usually inspire the same sense of enchantment.

Their beauty connects us to the wider riches of a vibrant nature hidden from most people’s sight in the dense rainforests of the tropical regions.

And they also connect us to nature in our own backyards. At certain times of the year, they spontaneously appear in our gardens and ponds. They can feel like special visitors from the natural world.

Dissecting human feelings for frogs

Yet relationships between people and frogs haven’t always been so positive. In fact, frogs occupy complicated places across cultures all over the world.

In the Western tradition, the legacy of biblical and classical sources was both negative and longstanding.

References to frogs in the Bible rendered them the instrument of divine anger as a swarming plague.

An etching from the late 1700s shows a plague of frogs.
An etching from the late 1700s shows a plague of frogs.
Wellcome Collection

Frogs challenged early modern zoological taxonomies, moving between classification as serpent, insect or reptile.

Perhaps their resistance to easy placement by humans explains the strong emotional language about them used by Swedish naturalist (and “father of modern taxonomy”) Carl Linnaeus.

When he considered the Amphibia in his 1758 Systema Naturae, he noted:

These foul and loathsome animals are abhorrent because of their cold body, pale colour, cartilaginous skeleton, filthy skin, fierce aspect, calculating eye, offensive smell, harsh voice, squalid habitation, and terrible venom.

In modern science, they sit in a branch of zoology, herpetology, that brings frogs together as “creeping animals” with snakes and lizards.

Frogs have also (or perhaps consequently) suffered in the service of science since at least the eighteenth century because it seemed to be possible to easily replicate experiments across multiple frog specimens.

Frogs were particularly crucial to the study of muscles and nerves. This led to ever more violent encounters between experimenters and frog bodies. Italian scientist Luigi Galvani, for example, did experiments in the late 18th century on legs of frogs to investigate what he thought of as “animal electricity”.

Legs of dissected frogs, and various metallic apparatus used to measure what was thought to be electricity flowing in animals
Scientist Luigi Galvani’s 18th-century diagrams of dissected frog legs and various metallic apparatus he used to measure what was thought to be electricity flowing in animals.
Library of Congress

In this sense, frogs were valued as significant scientific objects, their value lying in their flesh, their nervous systems, rather than in their status as living, feeling beings in the world.

In time, experiments with frogs moved beyond the laboratory into the classroom. In the 1930s, schoolchildren were expected to find frogs and bring them to school for dissection in biology classes.

This practice was, however, somewhat controversial, with opponents expressing sentimental attachment to frogs and concerns that such animal cruelty would lead to barbarism.

Recognising the fragility of frogs

So, our relationship with frogs is complicated. From the frogs of Aesop’s Fables to the meme Pepe the Frog, we have projected our own feelings and frustrations onto frogs, and exploited them for science and education.

Frogs have also borne the brunt of our failures as environmental stewards.

By 1990, the world was seeing a global pattern of decline in frog populations due to destruction and degradation of habitat for agriculture and logging, as well as a global amphibian pandemic caused by the chytrid fungus.

Climate change is also making life hard for many species. In 2022, over 40% of amphibian species (of which frogs and toads are by far the largest group) were threatened with extinction. Their vulnerability has seen the frog – especially the red-eyed tree frog – become a symbol for the environment more generally.

So we should delight in frogs and marvel at how beautiful and special they are while we still can, and consider how we might help save them.

Something to reflect on next time you are lucky enough to spot a frog.The Conversation

—————————–

This blog is written by Susan Broomhall, Director, Gender and Women’s History Research Centre, Australian Catholic University; Andrea Gaynor, Professor of History, The University of Western Australia, and Cabot Institute for the Environment member, Dr Andy Flack, Senior Lecturer in Modern and Environmental History, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.