Emma White– Research Fellow in Environmental Psychology, University of Surrey
Sarah Golding– Research Fellow in Health Psychology, University of Surrey
COVID-19 has shown that pandemics can seriously affect people’s physical and mental health. Stress, anxiety and depression have increased around the world, with the greatest effects for those living under the strictest lockdowns. Many people’s physical activity levels also fell during lockdown. Gardens, though, can help us push back against these negative effects.
Before the pandemic, having a garden was associated with better health and wellbeing, and this pattern has continued during COVID-19. In our own research on garden use during the UK’s first lockdown – published as a working paper this summer – we found that more frequent garden visits were associated with better wellbeing. Other work has also found that gardens have helped reduce mental distress during the pandemic.
With that in mind, here are five ways of using your garden that research suggests can improve your mental health. If you have access to an outdoor space and have been finding things difficult, you could try these out to boost your mood.
And if you’re feeling good now, you could use this chance to get ahead. Just as world leaders are being urged to prepare for the next pandemic, you can prepare your garden and develop habits now to better support your wellbeing in the future should there be another lockdown.
You don’t have to be a gardener to get active in your garden (although we think you should give it a go). Gardens are great places to be creative and provide lots of opportunities to get moving. Play hide and seek, do yoga on the lawn, build a bug hotel for insects to live in – anything you like!
And remember, if there’s another lockdown, being physically active in your garden can make up for lost opportunities to be active in other parts of your life.
2. Do nothing
Gardens help restore the ability to concentrate on demanding tasks, providing the perfect space for a break when working from home in a pandemic. Natural things – such as trees, plants and water – are particularly easy on the eye and demand little mental effort to look at. Simply sitting in a garden is therefore relaxing and beneficial to mental wellbeing.
To get your garden ready for break time, create a space in which to unwind. Surround yourself with soothing things, such as flowers.
Garden seating also seems to be key. People in our research told us they enjoyed relaxing in hammocks, chairs and benches. So, make time to sit and watch the clouds, or relax with a book and a cup of tea. And don’t feel guilty about it – taking a break is important for avoiding psychological fatigue.
3. Be alone
Gardens are places to escape the anxieties and demands of the world around us. They are particularly restorative because they are places where we can get away from our day-to-day life. In our research, some people talked about needing space from other household members and got this by hiding in the garden shed. Others hid away in the bathroom or bedroom.
Should there be another lockdown, remember that the garden is a good space to get away from work and other people. Perhaps create a hidden nook in your garden that you can hide out in for a few minutes. You’ll most likely return to work and life feeling refreshed and more productive.
4. Be social
Research also highlights the value of spending time with others outdoors. There are lots of ways to use your garden for socialising and building relationships. You could play a game outside, have a barbeque, chat to a neighbour over the fence, or invite a friend to drink hot chocolate in the snow (the Norwegians can teach us much about enjoying the outdoors during winter).
Of course, not everyone has a garden. But even if you don’t have outdoor space of your own, you can still follow some of these tips. Indoor plants can be used to create a more “natural” environment and have been shown to improve mood.
If you want to spend more social time outdoors, you could help at an allotment or community garden, as these are often highly social pursuits that involve working together outside. And if you want to do nothing at all, you could find a small local park to just sit and relax in.
Good access to natural environments supports health and wellbeing and can reduce health inequalities – yet access to green space remains very unequal. With growing recognition of the role of green space as a social determinant of health, how should health professionals respond? This year’s online NHS Forest conference will explore and share green space solutions at both a strategic and practical level, including insights from keynote speakers Judy Ling Wong, Dr Becca Lovell and Suzanne Tarrant.
Connect with children and nature champions around the world in The Trailhead. This new online community is free and open to practitioners, educators, parents, researchers and anyone committed to connecting children, families and communities to the benefits of nature. The Trailhead is your place to: Connect with peers and grow your network Join a global community of changemakers working to increase equitable access to nature Learn, lead and increase your impact Find potential conference co-presenters in The Trailhead’s 2022 Inside-Out International Conference Group SIGN UP
Jaime Zaplatosch VP, Green Schoolyards for Healthy Communities Children & Nature Network
Depending on where you are in the world, the start of the 2021-22 school year and the spread of the COVID-19 Delta variant might feel like “déjà vu all over again.” But, in fact, we are in a much better place to support going back to school fully in person this year. Many partners over many years have developed resources for taking learning outdoors — an approach that can provide a safer return to school now and enhance children’s learning and well-being all of the time.
RICHARD LOUVLEARNING OUTDOORS: Keeping students and teachers safer, improving education, and bringing healing during the pandemic
Eighteen months ago, school districts were mostly at a loss when it came to dealing with a global pandemic. Today, educators and communities have everything they need — if not in money, then certainly in good examples — to turn their schools into safer environments for students and teachers, and at the same time, improve educational outcomes. READ MORE
Ian Mell– Reader in Environmental & Landscape Planning, University of Manchester
The original plans for the temporary Marble Arch Mound in London depicted an inviting green space with thick vegetation and mature trees. The reality is far from that.
The sad-looking geometric hill has been criticised for featuring little other greenery than than the squares of wilting grass hanging to it. The views of Hyde Park and Oxford Street also leave much to be desired with obscured sight lines to other London landmarks. It is unsurprising then that people have also baulked at the £4.50-£8 entry fee, which is now being dropped after many visitors were refunded.
The poor design and construction have led the Mound to be labelled London’s “worst attraction”. Built to tempt shoppers back to Oxford Street, the Mound has ended up costing Westminster council £6 million. This is double the forecasted cost and has led to the resignation of the council’s deputy leader.
In its failure, the project undermines the Mayor of London’s strategic work to enhance the quantity and quality of green and open space across the metropolitan area. It is also comes at a time when green spaces and parks around the city (in Peckham, Bermondsey and Bromley) are under threat of being removed to make way for housing development.
Marble Arch Mound’s failure highlights a willingness by local councils to invest in green space if they promise to promote direct financial return while they decrease funds for existing parks, which are seen as economic burdens and low-money makers. And yet there are ways for cities to improve access to nature, play and community interaction with via investment in nature rather than focusing on tourist revenue.
Why this project in this location?
For those living in urban areas whose green spaces are under threat it might seem confusing why local councils would choose to fund tourist projects like the Mound when they are getting rid of permanent spaces that serve local communities in the long rather than short term.
Is it simply an economic choice, as it’s cheaper to sell assets and remove the costs of having to maintain them? Are local councils trying to raise long-term council and business tax revenue through increased property provision? Or do they view development as more worthy compared to the management of public parks?
Research in Liverpool has shown that local authorities are under significant pressures to meet budgetary demands meaning all these considerations are being made. In some cases, sales are deemed politically practical regardless of the problems associated with a lack of accessible parks and green space.
However, the pandemic has reinforced the need for local councils, and society more generally, to consider its health, wellbeing, and the promotion of social interaction provided by the natural environment – especially in areas of low income or diverse ethnicity. Over the last 20 months, enhancement and maintenance of local parks has been critical to public health. Evidence from the Office for National Stastistics, Natural England and Public Health England provides an argument for more and better provision of green space in support of this view.
Working with pop-up parks in the future
Pop-up parks are not a bad idea. The use of pop-up forests and forest bathing pods in Liverpool generated excitement when they were used in the summer of 2019. Additional examples from the US and Australia also highlight the ways in which pop-up parks can add a vibrancy to urban areas.
However, these examples were well thought through and didn’t cost £6 million. They were more discreet in their scale and had more interactive elements to their designs that drew people in. The Marble Arch Mound went big and bold and is now viewed as a folly, much like the Garden Bridge, for failing to meet expectations.
London, though, has numerous examples of innovative partnerships developed between businesses, local councils and the environment sector that have brought underused and undervalued spaces back into use. For example, the Wild West End partnership champions biodiversity and green space provision in the same area as the Marble Arch Mound, but has delivered projects that have been seen as far more successful.
The partnership’s small park in Baker Street, built around an area of decking with planters containing silver birch trees and perennial plants, was created to improve air quality and biodiversity. It also serves as a spot for people to sit and host events in a busy area of the city. Two years since it opened in 2019 the space has had tangible environmental benefits, including welcoming many pollinators, and is loved by local residents, those employed in the area and visitors.
Likewise, environmental charity Thames 21, has worked extensively with partners to improve London’s waterways and engage people with the environment. They, and other organisations including Groundwork, have created great green spaces via volunteering and corporate social responsibility programmes that focus on getting people to engage directly with nature.
Westminster council purports that the temporary structure is part of their bid for a “greener, smarter, future, together”. Programmes like Wild West End, Thames 21 and Groundwork are actually achieving this vision with their green spaces, which focus on engaging the local community and improving wellbeing while striving to provide better green urban spaces that aid the local environment.
The ways in which these organisations have worked over a prolonged period in dedicated locations show that the provision of additional amenities such as play areas, sports pitches, or space to socialise can thrive compared to gimmicks or projects that prioritise economic development over ecology and community. They also highlight that a range of green and blue spaces including parks, street trees, open grassed areas and canals can meet local and city-wide health and recreation needs.
Pop-up projects like the Marble Arch Mound can become places that people cherish and important green additions that work with urban environments. However, if green spaces, short and long term, are community driven and have accessible urban nature at their heart, rather than economic concerns like the Marble Arch Mound, local communities and local councils can benefit.
Kamran Mahroof– Assistant Professor, Supply Chain Analytics, University of Bradford
Sankar Sivarajah– Professor of Technology Management and Circular Economy, University of Bradford
The COVID pandemic has shown the fragility of our global food supply chains, with many supermarkets and restaurants in almost every country having experienced food shortages. Millions of people in the UK alone have experienced severe food insecurity during COVID-19, according to a recent report by the country’s Foods Standards Agency. But food shortages were prevalent long before the pandemic.
At the same time, one-third of all food produced each year is squandered or spoiled before it can be consumed. Research also suggests that high-income countries waste as much food as sub-Saharan Africa produces.
This food waste then ends up in landfills to rot – which releases greenhouse gases. And when this is combined with the amount of energy it takes to produce, manufacture, transport and store this food, it contributes a staggering 3 billion tonnes of carbon dioxide to our planet. To put that in context, if food waste was a country, it would be the third-highest emitter of greenhouse gases in the world, after the US and China.
But the good news is there are numerous techniques, technologies and policies that together could help reduce global food waste at every point in the process of producing and consuming it.
Why is food wasted?
According to the Food and Agriculture Organisation for the United Nations, lack of infrastructure, limited knowledge on storage and food handling, combined with unfavourable climatic conditions, can lead to a lot of food spoilage and waste in low-income countries.
On the other hand, in high-income countries, aesthetic preferences and arbitrary sell-by dates mean food easily becomes waste. Cosmetic blemishes, produce that is too ripe, too big, too little or even the wrong shape can lead to perfectly good fruits and vegetables going to waste.
As the global population continues to increase, it places real pressure on world food production. Indeed, the industry will need to grow by at least two-thirds by 2050 to ensure adequate nutrition for everyone in the world.
Yet, despite the dire need to become more resourceful, food waste and loss is at an all-time high. Making it clear that unless prompt action is taken, food shortages will soon become a long-term reality.
What can be done?
The key to tackling this issue is to have a resilient and resourceful “farm-to-fork” approach to help reduce food waste and to ensure the future of food security. Here are some things that can help combat food waste:
AI drones and precision farming
Collaboration with food producers and more investment in technological applications and overall infrastructure at the earlier stages of the food supply chain can drastically improve food waste and loss in low-income countries.
This is important because plant diseases and pests – along with poor harvesting techniques – can be a big factor in the high levels of food waste at this point in the food supply chain.
Our research also indicates that artificial intelligence (AI) powered drones can help farmers become more resourceful and reduce the overuse of pesticides in food production. This is important because pesticides can adversely affect the food ecosystem. They pollute water, deplete soil fertility and contaminate turf – all of which can result in food loss and waste. This approach also enhances crop yield and reduces operational costs as well as improves the health of livestock. So it’s also better for the environment.
Target shoppers’ wallets
A big part of the food waste problem is changing how we shop and view food and our mindset around what constitutes waste. But research shows the best way to tackle food waste among consumers is to highlight the potential money that can be saved as well as the “feel-good factor”, or moral value, of doing a good thing for the environment.
A recent study with households in London, UK and Ontario, Canada, found that a two-week money-based intervention – called “reduce food waste, save money” – helped participants to throw away 30% less food. Participants were given local information on food waste and costs, along with tips on how to improve food planning, efficiently purchase, store, and prepare food – and how to use leftovers to create new meals.
Similarly, new technology can help commercial kitchens reduce food waste by directly connecting behaviour changes to increased profits. For example, the Winnow software system calculates the costs of discarded food, correlating food waste to sales. This AI-powered system has allowed Ikea stores to reduce food waste by 50% in 2020, saving 1.2 million meals in the process.
While the problem of food waste can feel quite out of your hands as a consumer, there are things you can do to help.
Things like supporting businesses or restaurants that use waste foods in their products or meals. Planning your meals around sell-by dates. Not throwing out food if it’s a bit wilted or bruised and only buying what you need – especially on special occasions where food can often go uneaten and to waste.
You can also show supermarkets that “wonky” fruit and veggies are just as good as the “normal” shaped produce by buying these over the perfect looking pears or potatoes.
Ultimately, it’s not going to be any single thing that solves food waste, but a collective approach can enable us to make the changes that need to happen.
Bonnie Waring– Senior Lecturer, Grantham Institute – Climate Change and Environment, Imperial College London
One morning in 2009, I sat on a creaky bus winding its way up a mountainside in central Costa Rica, light-headed from diesel fumes as I clutched my many suitcases. They contained thousands of test tubes and sample vials, a toothbrush, a waterproof notebook and two changes of clothes.
I was on my way to La Selva Biological Station, where I was to spend several months studying the wet, lowland rainforest’s response to increasingly common droughts. On either side of the narrow highway, trees bled into the mist like watercolours into paper, giving the impression of an infinite primeval forest bathed in clouds.
You can listen to more articles from The Conversation, narrated by Noa, here.
As I gazed out of the window at the imposing scenery, I wondered how I could ever hope to understand a landscape so complex. I knew that thousands of researchers across the world were grappling with the same questions, trying to understand the fate of tropical forests in a rapidly changing world.
Our society asks so much of these fragile ecosystems, which control freshwater availability for millions of people and are home to two thirds of the planet’s terrestrial biodiversity. And increasingly, we have placed a new demand on these forests – to save us from human-caused climate change.
Plants absorb CO₂ from the atmosphere, transforming it into leaves, wood and roots. This everyday miracle has spurred hopes that plants – particularly fast growing tropical trees – can act as a natural brake on climate change, capturing much of the CO₂ emitted by fossil fuel burning. Across the world, governments, companies and conservation charities have pledged to conserve or plant massive numbers of trees.
But the fact is that there aren’t enough trees to offset society’s carbon emissions – and there never will be. I recently conducted a review of the available scientific literature to assess how much carbon forests could feasibly absorb. If we absolutely maximised the amount of vegetation all land on Earth could hold, we’d sequester enough carbon to offset about ten years of greenhouse gas emissions at current rates. After that, there could be no further increase in carbon capture.
Yet the fate of our species is inextricably linked to the survival of forests and the biodiversity they contain. By rushing to plant millions of trees for carbon capture, could we be inadvertently damaging the very forest properties that make them so vital to our wellbeing? To answer this question, we need to consider not only how plants absorb CO₂, but also how they provide the sturdy green foundations for ecosystems on land.
Plants convert CO₂ gas into simple sugars in a process known as photosynthesis. These sugars are then used to build the plants’ living bodies. If the captured carbon ends up in wood, it can be locked away from the atmosphere for many decades. As plants die, their tissues undergo decay and are incorporated into the soil.
While this process naturally releases CO₂ through the respiration (or breathing) of microbes that break down dead organisms, some fraction of plant carbon can remain underground for decades or even centuries. Together, land plants and soils hold about 2,500 gigatonnes of carbon – about three times more than is held in the atmosphere.
Because plants (especially trees) are such excellent natural storehouses for carbon, it makes sense that increasing the abundance of plants across the world could draw down atmospheric CO₂ concentrations.
Plants need four basic ingredients to grow: light, CO₂, water and nutrients (like nitrogen and phosphorus, the same elements present in plant fertiliser). Thousands of scientists across the world study how plant growth varies in relation to these four ingredients, in order to predict how vegetation will respond to climate change.
This is a surprisingly challenging task, given that humans are simultaneously modifying so many aspects of the natural environment by heating the globe, altering rainfall patterns, chopping large tracts of forest into tiny fragments and introducing alien species where they don’t belong. There are also over 350,000 species of flowering plants on land and each one responds to environmental challenges in unique ways.
Due to the complicated ways in which humans are altering the planet, there is a lot of scientific debate about the precise quantity of carbon that plants can absorb from the atmosphere. But researchers are in unanimous agreement that land ecosystems have a finite capacity to take up carbon.
If we ensure trees have enough water to drink, forests will grow tall and lush, creating shady canopies that starve smaller trees of light. If we increase the concentration of CO₂ in the air, plants will eagerly absorb it – until they can no longer extract enough fertiliser from the soil to meet their needs. Just like a baker making a cake, plants require CO₂, nitrogen and phosphorus in particular ratios, following a specific recipe for life.
In recognition of these fundamental constraints, scientists estimate that the earth’s land ecosystems can hold enough additional vegetation to absorb between 40 and 100 gigatonnes of carbon from the atmosphere. Once this additional growth is achieved (a process which will take a number of decades), there is no capacity for additional carbon storage on land.
But our society is currently pouring CO₂ into the atmosphere at a rate of ten gigatonnes of carbon a year. Natural processes will struggle to keep pace with the deluge of greenhouse gases generated by the global economy. For example, I calculated that a single passenger on a round trip flight from Melbourne to New York City will emit roughly twice as much carbon (1600 kg C) as is contained in an oak tree half a meter in diameter (750 kg C).
Peril and promise
Despite all these well recognised physical constraints on plant growth, there is a proliferating number of large scale efforts to increase vegetation cover to mitigate the climate emergency – a so called “nature-based” climate solution. The vastmajority of these efforts focus on protecting or expanding forests, as trees contain many times more biomass than shrubs or grasses and therefore represent greater carbon capture potential.
Yet fundamental misunderstandings about carbon capture by land ecosystems can have devastating consequences, resulting in losses of biodiversity and an increase in CO₂ concentrations. This seems like a paradox – how can planting trees negatively impact the environment?
The answer lies in the subtle complexities of carbon capture in natural ecosystems. To avoid environmental damage, we must refrain from establishing forests where they naturally don’t belong, avoid “perverse incentives” to cut down existing forest in order to plant new trees, and consider how seedlings planted today might fare over the next several decades.
Before undertaking any expansion of forest habitat, we must ensure that trees are planted in the right place because not all ecosystems on land can or should support trees. Planting trees in ecosystems that are normally dominated by other types of vegetation often fails to result in long term carbon sequestration.
One particularly illustrative example comes from Scottish peatlands – vast swathes of land where the low-lying vegetation (mostly mosses and grasses) grows in constantly soggy, moist ground. Because decomposition is very slow in the acidic and waterlogged soils, dead plants accumulate over very long periods of time, creating peat. It’s not just the vegetation that is preserved: peat bogs also mummify so-called “bog bodies” – the nearly intact remains of men and women who died millennia ago. In fact, UK peatlands contain 20 times more carbon than found in the nation’s forests.
But in the late 20th century, some Scottish bogs were drained for tree planting. Drying the soils allowed tree seedlings to establish, but also caused the decay of the peat to speed up. Ecologist Nina Friggens and her colleagues at the University of Exeter estimated that the decomposition of drying peat released more carbon than the growing trees could absorb. Clearly, peatlands can best safeguard the climate when they are left to their own devices.
The same is true of grasslands and savannahs, where fires are a natural part of the landscape and often burn trees that are planted where they don’t belong. This principle also applies to Arctic tundras, where the native vegetation is covered by snow throughout the winter, reflecting light and heat back to space. Planting tall, dark-leaved trees in these areas can increase absorption of heat energy, and lead to local warming.
But even planting trees in forest habitats can lead to negative environmental outcomes. From the perspective of both carbon sequestration and biodiversity, all forests are not equal – naturally established forests contain more species of plants and animals than plantation forests. They often hold more carbon, too. But policies aimed at promoting tree planting can unintentionally incentivise deforestation of well established natural habitats.
A recent high-profile example concerns the Mexican government’s Sembrando Vida programme, which provides direct payments to landowners for planting trees. The problem? Many rural landowners cut down well established older forest to plant seedlings. This decision, while quite sensible from an economic point of view, has resulted in the loss of tens of thousands of hectares of mature forest.
This example demonstrates the risks of a narrow focus on trees as carbon absorption machines. Many well meaning organisations seek to plant the trees which grow the fastest, as this theoretically means a higher rate of CO₂ “drawdown” from the atmosphere.
Yet from a climate perspective, what matters is not how quickly a tree can grow, but how much carbon it contains at maturity, and how long that carbon resides in the ecosystem. As a forest ages, it reaches what ecologists call a “steady state” – this is when the amount of carbon absorbed by the trees each year is perfectly balanced by the CO₂ released through the breathing of the plants themselves and the trillions of decomposer microbes underground.
This phenomenon has led to an erroneous perception that old forests are not useful for climate mitigation because they are no longer growing rapidly and sequestering additional CO₂. The misguided “solution” to the issue is to prioritise tree planting ahead of the conservation of already established forests. This is analogous to draining a bathtub so that the tap can be turned on full blast: the flow of water from the tap is greater than it was before – but the total capacity of the bath hasn’t changed. Mature forests are like bathtubs full of carbon. They are making an important contribution to the large, but finite, quantity of carbon that can be locked away on land, and there is little to be gained by disturbing them.
What about situations where fast growing forests are cut down every few decades and replanted, with the extracted wood used for other climate-fighting purposes? While harvested wood can be a very good carbon store if it ends up in long lived products (like houses or other buildings), surprisingly little timber is used in this way.
Similarly, burning wood as a source of biofuel may have a positive climate impact if this reduces total consumption of fossil fuels. But forests managed as biofuel plantations provide little in the way of protection for biodiversity and some research questions the benefits of biofuels for the climate in the first place.
Fertilise a whole forest
Scientific estimates of carbon capture in land ecosystems depend on how those systems respond to the mounting challenges they will face in the coming decades. All forests on Earth – even the most pristine – are vulnerable to warming, changes in rainfall, increasingly severe wildfires and pollutants that drift through the Earth’s atmospheric currents.
Some of these pollutants, however, contain lots of nitrogen (plant fertiliser) which could potentially give the global forest a growth boost. By producing massive quantities of agricultural chemicals and burning fossil fuels, humans have massively increased the amount of “reactive” nitrogen available for plant use. Some of this nitrogen is dissolved in rainwater and reaches the forest floor, where it can stimulate tree growth in some areas.
As a young researcher fresh out of graduate school, I wondered whether a type of under-studied ecosystem, known as seasonally dry tropical forest, might be particularly responsive to this effect. There was only one way to find out: I would need to fertilise a whole forest.
Working with my postdoctoral adviser, the ecologist Jennifer Powers, and expert botanist Daniel Pérez Avilez, I outlined an area of the forest about as big as two football fields and divided it into 16 plots, which were randomly assigned to different fertiliser treatments. For the next three years (2015-2017) the plots became among the most intensively studied forest fragments on Earth. We measured the growth of each individual tree trunk with specialised, hand-built instruments called dendrometers.
We used baskets to catch the dead leaves that fell from the trees and installed mesh bags in the ground to track the growth of roots, which were painstakingly washed free of soil and weighed. The most challenging aspect of the experiment was the application of the fertilisers themselves, which took place three times a year. Wearing raincoats and goggles to protect our skin against the caustic chemicals, we hauled back-mounted sprayers into the dense forest, ensuring the chemicals were evenly applied to the forest floor while we sweated under our rubber coats.
Unfortunately, our gear didn’t provide any protection against angry wasps, whose nests were often concealed in overhanging branches. But, our efforts were worth it. After three years, we could calculate all the leaves, wood and roots produced in each plot and assess carbon captured over the study period. We found that most trees in the forest didn’t benefit from the fertilisers – instead, growth was strongly tied to the amount of rainfall in a given year.
This suggests that nitrogen pollution won’t boost tree growth in these forests as long as droughts continue to intensify. To make the same prediction for other forest types (wetter or drier, younger or older, warmer or cooler) such studies will need to be repeated, adding to the library of knowledge developed through similar experiments over the decades. Yet researchers are in a race against time. Experiments like this are slow, painstaking, sometimes backbreaking work and humans are changing the face of the planet faster than the scientific community can respond.
Humans need healthy forests
Supporting natural ecosystems is an important tool in the arsenal of strategies we will need to combat climate change. But land ecosystems will never be able to absorb the quantity of carbon released by fossil fuel burning. Rather than be lulled into false complacency by tree planting schemes, we need to cut off emissions at their source and search for additional strategies to remove the carbon that has already accumulated in the atmosphere.
Does this mean that current campaigns to protect and expand forest are a poor idea? Emphatically not. The protection and expansion of natural habitat, particularly forests, is absolutely vital to ensure the health of our planet. Forests in temperate and tropical zones contain eight out of every ten species on land, yet they are under increasing threat. Nearly half of our planet’s habitable land is devoted to agriculture, and forest clearing for cropland or pasture is continuing apace.
Meanwhile, the atmospheric mayhem caused by climate change is intensifying wildfires, worsening droughts and systematically heating the planet, posing an escalating threat to forests and the wildlife they support. What does that mean for our species? Again and again, researchers have demonstrated strong links between biodiversity and so-called “ecosystem services” – the multitude of benefits the natural world provides to humanity.
Carbon capture is just one ecosystem service in an incalculably long list. Biodiverse ecosystems provide a dizzying array of pharmaceutically active compounds that inspire the creation of new drugs. They provide food security in ways both direct (think of the millions of people whose main source of protein is wild fish) and indirect (for example, a large fraction of crops are pollinated by wild animals).
Natural ecosystems and the millions of species that inhabit them still inspire technological developments that revolutionise human society. For example, take the polymerase chain reaction (“PCR”) that allows crime labs to catch criminals and your local pharmacy to provide a COVID test. PCR is only possible because of a special protein synthesised by a humble bacteria that lives in hot springs.
As an ecologist, I worry that a simplistic perspective on the role of forests in climate mitigation will inadvertently lead to their decline. Many tree planting efforts focus on the number of saplings planted or their initial rate of growth – both of which are poor indicators of the forest’s ultimate carbon storage capacity and even poorer metric of biodiversity. More importantly, viewing natural ecosystems as “climate solutions” gives the misleading impression that forests can function like an infinitely absorbent mop to clean up the ever increasing flood of human caused CO₂ emissions.
Luckily, many big organisations dedicated to forest expansion are incorporating ecosystem health and biodiversity into their metrics of success. A little over a year ago, I visited an enormous reforestation experiment on the Yucatán Peninsula in Mexico, operated by Plant-for-the-Planet – one of the world’s largest tree planting organisations. After realising the challenges inherent in large scale ecosystem restoration, Plant-for-the-Planet has initiated a series of experiments to understand how different interventions early in a forest’s development might improve tree survival.
But that is not all. Led by Director of Science Leland Werden, researchers at the site will study how these same practices can jump-start the recovery of native biodiversity by providing the ideal environment for seeds to germinate and grow as the forest develops. These experiments will also help land managers decide when and where planting trees benefits the ecosystem and where forest regeneration can occur naturally.
Viewing forests as reservoirs for biodiversity, rather than simply storehouses of carbon, complicates decision making and may require shifts in policy. I am all too aware of these challenges. I have spent my entire adult life studying and thinking about the carbon cycle and I too sometimes can’t see the forest for the trees. One morning several years ago, I was sitting on the rainforest floor in Costa Rica measuring CO₂ emissions from the soil – a relatively time intensive and solitary process.
As I waited for the measurement to finish, I spotted a strawberry poison dart frog – a tiny, jewel-bright animal the size of my thumb – hopping up the trunk of a nearby tree. Intrigued, I watched her progress towards a small pool of water held in the leaves of a spiky plant, in which a few tadpoles idly swam. Once the frog reached this miniature aquarium, the tiny tadpoles (her children, as it turned out) vibrated excitedly, while their mother deposited unfertilised eggs for them to eat. As I later learned, frogs of this species (Oophaga pumilio) take very diligent care of their offspring and the mother’s long journey would be repeated every day until the tadpoles developed into frogs.
It occurred to me, as I packed up my equipment to return to the lab, that thousands of such small dramas were playing out around me in parallel. Forests are so much more than just carbon stores. They are the unknowably complex green webs that bind together the fates of millions of known species, with millions more still waiting to be discovered. To survive and thrive in a future of dramatic global change, we will have to respect that tangled web and our place in it.
Pep Canadell– Chief research scientist, Climate Science Centre, CSIRO Oceans and Atmosphere; and Executive Director, Global Carbon Project, CSIRO Joelle Gergis– Senior Lecturer in Climate Science, Australian National University Malte Meinshausen– A/Prof., School of Earth Sciences, The University of Melbourne Mark Hemer– Principal Research Scientist, Oceans and Atmosphere, CSIRO Michael Grose-Climate projections scientist, CSIRO
Earth has warmed 1.09℃ since pre-industrial times and many changes such as sea-level rise and glacier melt are now virtually irreversible, according to the most sobering report yet by the Intergovernmental Panel on Climate Change (IPCC).
The report also found escape from human-caused climate change is no longer possible. Climate change is now affecting every continent, region and ocean on Earth, and every facet of the weather.
The long-awaited report is the sixth assessment of its kind since the panel was formed in 1988. It will give world leaders the most timely, accurate information about climate change ahead of a crucial international summit in Glasgow, Scotland in November.
The IPCC is the peak climate science body of the United Nations and the World Meteorological Organization. It is the global authority on the state of Earth’s climate and how human activities affect it. We are authors of the latest IPCC report and have drawn from the work of thousands of scientists from around the world to produce this new assessment.
Sadly, there is hardly any good news in the 3,900 pages of text released today. But there is still time to avert the worst damage, if humanity chooses to.
It’s unequivocal: humans are warming the planet
For the first time, the IPCC states unequivocally — leaving absolutely no room for doubt – humans are responsible for the observed warming of the atmosphere, lands and oceans.
The IPCC finds Earth’s global surface temperature warmed 1.09℃ between 1850-1900 and the last decade. This is 0.29℃ warmer than in the previous IPCC report in 2013. (It should be noted that 0.1℃ of the increase is due to data improvements.)
The IPCC recognises the role of natural changes to the Earth’s climate. However, it finds 1.07℃ of the 1.09℃ warming is due to greenhouse gases associated with human activities. In other words, pretty much all global warming is due to humans.
Global surface temperature has warmed faster since 1970 than in any other 50-year period over at least the last 2,000 years, with the warming also reaching ocean depths below 2,000 metres.
The IPCC says human activities have also affected global precipitation (rain and snow). Since 1950, total global precipitation has increased, but while some regions have become wetter, others have become drier.
The frequency and intensity of heavy precipitation events have increased over most land areas. This is because the warmer atmosphere is able to hold more moisture — about 7% more for each additional degree of temperature — which makes wet seasons and rainfall events wetter.
Higher concentrations of CO₂, growing faster
Present-day global concentrations of atmospheric carbon dioxide (CO₂) are higher and rising faster than at any time in at least the past two million years.
The speed at which atmospheric CO₂ has increased since the industrial revolution (1750) is at least ten times faster than at any other time during the last 800,000 years, and between four and five times faster than during the last 56 million years.
About 85% of CO₂ emissions are from burning fossil fuels. The remaining 15% are generated from land use change, such as deforestation and degradation.
Concentrations of other greenhouse gases are not doing any better. Both methane and nitrous oxide, the second and third biggest contributors to global warming after CO₂, have also increased more quickly.
Methane emissions from human activities largely come from livestock and the fossil fuel industry. Nitrous oxide emissions largely come from the use of nitrogen fertiliser on crops.
Extreme weather on the rise
Hot extremes, heatwaves and heavy rain have also become more frequent and intense across most land regions since 1950, the IPCC confirms.
The report highlights that some recently observed hot extremes, such as the Australian summer of 2012–2013, would have been extremely unlikely without human influence on the climate.
Human influence has also been detected for the first time in compounded extreme events. For example, incidences of heatwaves, droughts and fire weather happening at the same time are now more frequent. These compound events have been seen in Australia, Southern Europe, Northern Eurasia, parts of the Americas and African tropical forests.
Oceans: hotter, higher and more acidic
Oceans absorb 91% of the energy from the increased atmospheric greenhouse gases. This has led to ocean warming and more marine heatwaves, particularly over the past 15 years.
Marine heatwaves cause the mass death of marine life, such as from coral bleaching events. They also cause algal blooms and shifts in the composition of species. Even if the world restricts warming to 1.5-2℃, as is consistent with the Paris Agreement, marine heatwaves will become four times more frequent by the end of the century.
Melting ice sheets and glaciers, along with the expansion of the ocean as it warms, have led to a global mean sea level increase of 0.2 metres between 1901 and 2018. But, importantly, the speed sea level is rising is accelerating: 1.3 millimetres per year during 1901-1971, 1.9mm per year during 1971-2006, and 3.7mm per year during 2006-2018.
Ocean acidification, caused by the uptake of CO₂, has occurred over all oceans and is reaching depths beyond 2,000m in the Southern Ocean and North Atlantic.
Many changes are already irreversible
The IPCC says if Earth’s climate was stabilised soon, some climate change-induced damage could not be reversed within centuries, or even millennia. For example, global warming of 2℃ this century will lead to average global sea level rise of between two and six metres over 2,000 years, and much more for higher emission scenarios.
Globally, glaciers have been synchronously retreating since 1950 and are projected to continue to melt for decades after the global temperature is stabilised. Meanwhile the acidification of the deep ocean will remain for thousands of years after CO₂ emissions cease.
The report does not identify any possible abrupt changes that would lead to an acceleration of global warming during this century – but does not rule out such possibilities.
The prospect of permafrost (frozen soils) in Alaska, Canada, and Russia crossing a tipping point has been widely discussed. The concern is that as frozen ground thaws, large amounts of carbon accumulated over thousands of years from dead plants and animals could be released as they decompose.
The report does not identify any globally significant abrupt change in these regions over this century, based on currently available evidence. However, it projects permafrost areas will release about 66 billion tonnes of CO₂ for each additional degree of warming. These emissions are irreversible during this century under all warming scenarios.
How we can stabilise the climate
Earth’s surface temperature will continue to increase until at least 2050 under all emissions scenarios considered in the report. The assessment shows Earth could well exceed the 1.5℃ warming limit by early 2030s.
If we reduce emissions sufficiently, there is only a 50% chance global temperature rise will stay around 1.5℃ (including a temporary overshoot of up to 0.1℃). To get Earth back to below 1.5℃ warming, CO₂ would need to be removed from the atmosphere using negative emissions technologies or nature-based solutions.
Global warming stays below 2℃ during this century only under scenarios where CO₂ emissions reach net-zero around or after 2050.
The IPCC analysed future climate projections from dozens of climate models, produced by more than 50 modelling centres around the world. It showed global average surface temperature rises between 1-1.8℃ and 3.3-5.7℃ this century above pre-industrial levels for the lowest and highest emission scenarios, respectively. The exact increase the world experiences will depend on how much more greenhouse gases are emitted.
The report states, with high certainty, that to stabilise the climate, CO₂ emissions must reach net zero, and other greenhouse gas emissions must decline significantly.
We also know, for a given temperature target, there’s a finite amount of carbon we can emit before reaching net zero emissions. To have a 50:50 chance of halting warming at around 1.5℃, this quantity is about 500 billion tonnes of CO₂.
At current levels of CO₂ emissions this “carbon budget” would be used up within 12 years. Exhausting the budget will take longer if emissions begin to decline.
The IPCC’s latest findings are alarming. But no physical or environmental impediments exist to hold warming to well below 2℃ and limit it to around 1.5℃ – the globally agreed goals of the Paris Agreement. Humanity, however, must choose to act.
New analysis by environmental charity Keep Britain Tidy has revealed that 70% of people who live in urban areas in towns and cities across England do not have suitable access to good quality green space. This rises to 75.8% in the most deprived areas.
The findings are based on those who live within 800m (or a ten-minute walk) of a Green Flag Award accredited green space – the Government’s own standard for what constitutes a good-quality park.
The study found that in London there is a good provision of quality green space, with 62% of the urban population within walking distance of a park accredited with the Green Flag Award. However, London is far above any other region in the UK. The region with the second highest access for its urban residents is East Midlands – with just 29%.
Cities in the North West of England in particular have little access. In the region, fewer than a quarter of those who live in urban areas (24%) have access to a Green Flag Award accredited park.
The findings correlate with the Heritage Lottery Fund’s ‘State of UK Public Parks 2016’ report which found the London and East Midlands were the two regions least likely to be hit by funding cuts to parks.
The analysis focused on urban regions only to exclude rural areas, which may have access to very good quality but unaccredited space such as national parks.
In urban environments there is a difference between any green space and a ‘quality’ one. A certified Green Flag Award park will offer a healthy, clean, sustainable, well-maintained and safe environment for people to relax, socialise and exercise in.
The findings are particularly worrying after a year-and-a-half of lockdowns which have meant that, for many living in urban environments, public parks represent the only green space available to them.
Highlighting the importance of urban green space, a World Health Organisation report published in 2017 concluded that ‘urban green space is a necessary component for delivering healthy, sustainable and liveable cities. Urban green space interventions can deliver positive health, social and environmental outcomes for all population groups, particularly among lower socioeconomic status groups. There are very few, if any, other public health interventions that can achieve all of this’.
However, the WHO report also pointed out that urban green spaces must be effectively managed in order for them to provide the significant benefits. The report said: “Management and maintenance of urban green space is paramount so that users perceive it as safe, clean and cared for. Negligent management and maintenance sends a signal that nobody takes care of the area and thus can encourage anti-social behaviour.”
The Green Flag Award is the only tool that allows those charged with managing our urban green spaces to benchmark the quality of those spaces and is the recognised international standard.
“The environment around us shapes our quality of life, and access to quality green space has never been more vital than it has been over the course of the pandemic, showing how much we rely on it for our wellbeing, both mental and physical. We believe everyone should have access to one.
“It’s therefore very worrying that the vast majority of those living in urban environments do not have access to a green space that, by the Government’s own standards, can be considered of good quality.
“As such, we are calling for increased investment across the country. It is money well spent – for example in Sheffield, the Government’s own analysis showed that for every £1 spent on maintaining parks, there is a benefit of £34 in health costs saved.”
A report from Public Health England released last year entitled ‘Improving Access to Green Space’ highlighted the issues, stating that: It should be a concern for all of us that access to good quality green spaces varies greatly depending on where we live. The most economically deprived areas often have less available public greenspace.
But scientists are still trying to unravel how and why swimming, in particular, produces these brain-enhancing effects.
As a neurobiologist trained in brain physiology, a fitness enthusiast and a mom, I spend hours at the local pool during the summer. It’s not unusual to see children gleefully splashing and swimming while their parents sunbathe at a distance – and I’ve been one of those parents observing from the poolside plenty of times. But if more adults recognized the cognitive and mental health benefits of swimming, they might be more inclined to jump in the pool alongside their kids.
New and improved brain cells and connections
Until the 1960s, scientists believed that the number of neurons and synaptic connections in the human brain were finite and that, once damaged, these brain cells could not be replaced. But that idea was debunked as researchers began to see ample evidence for the birth of neurons, or neurogenesis, in adult brains of humans and other animals.
In studies in fish, scientists have observed changes in genes responsible for increasing brain-derived neurotrophic factor levels as well as enhanced development of the dendritic spines – protrusions on the dendrites, or elongated portions of nerve cells – after eight weeks of exercise compared with controls. This complements studies in mammals where brain-derived neurotrophic factor is known to increase neuronal spine density. These changes have been shown to contribute to improved memory, mood and enhanced cognition in mammals. The greater spine density helps neurons build new connections and send more signals to other nerve cells. With the repetition of signals, connections can become stronger.
But what’s special about swimming?
Researchers don’t yet know what swimming’s secret sauce might be. But they’re getting closer to understanding it.
In one study in rats, swimming was shown to stimulate brain pathways that suppress inflammation in the hippocampus and inhibit apoptosis, or cell death. The study also showed that swimming can help support neuron survival and reduce the cognitive impacts of aging. Although researchers do not yet have a way to visualize apoptosis and neuronal survival in people, they do observe similar cognitive outcomes.
One of the more enticing questions is how, specifically, swimming enhances short- and long-term memory. To pinpoint how long the beneficial effects may last, researchers trained rats to swim for 60 minutes daily for five days per week. The team then tested the rats’ memory by having them swim through a radial arm water maze containing six arms, including one with a hidden platform.
Rats got six attempts to swim freely and find the hidden platform. After just seven days of swim training, researchers saw improvements in both short- and long-term memories, based on a reduction in the errors rats made each day. The researchers suggested that this boost in cognitive function could provide a basis for using swimming as a way to repair learning and memory damage caused by neuropsychiatric diseases in humans.
Although the leap from studies in rats to humans is substantial, research in people is producing similar results that suggest a clear cognitive benefit from swimming across all ages. For instance, in one study looking at the impact of swimming on mental acuity in the elderly, researchers concluded that swimmers had improved mental speed and attention compared with nonswimmers. However, this study is limited in its research design, since participants were not randomized and thus those who were swimmers prior to the study may have had an unfair edge.
Another study compared cognition between land-based athletes and swimmers in the young adult age range. While water immersion itself did not make a difference, the researchers found that 20 minutes of moderate-intensity breaststroke swimming improved cognitive function in both groups.
Kids get a boost from swimming too
The brain-enhancing benefits from swimming appear to also boost learning in children.
Another research group recently looked at the link between physical activity and how children learn new vocabulary words. Researchers taught children age 6-12 the names of unfamiliar objects. Then they tested their accuracy at recognizing those words after doing three activities: coloring (resting activity), swimming (aerobic activity) and a CrossFit-like exercise (anaerobic activity) for three minutes.
They found that children’s accuracy was much higher for words learned following swimming compared with coloring and CrossFit, which resulted in the same level of recall. This shows a clear cognitive benefit from swimming versus anaerobic exercise, though the study does not compare swimming with other aerobic exercises. These findings imply that swimming for even short periods of time is highly beneficial to young, developing brains.
The details of the time or laps required, the style of swim and what cognitive adaptations and pathways are activated by swimming are still being worked out. But neuroscientists are getting much closer to putting all the clues together.
For centuries, people have been in search of a fountain of youth. Swimming just might be the closest we can get.