Mature trees clean air, lower stress, boost happiness, reduce flood risk – and even save municipal money. So why are they cut down when cities develop – and how should the UN’s new urban agenda protect them?

 Sheffield residents campaigned to save mature lime trees which the city council earmarked to be felled. Photograph: Christopher Thomond for the Guardian

 

The skyline along Manhattan’s Upper Fifth Avenue, where it flanks Central Park, is dominated by vast, verdant clouds of American elm trees. Their high-arched branches and luminous green canopies form – as historian Jill Jones puts it – “a beautiful cathedral of shade”. When she started researching her new book, Urban Forests, she’d have struggled to identify the species – but now, she says, “when I see one, I say ‘Oh my goodness, this is a rare survivor,’ and deeply appreciate the fact that it’s there.”

The American elm was once America’s most beloved and abundant city tree. It liked urban soil, and its branches spread out a safe distance above traffic, to provide the dappled shade that cities depended on before air conditioning.

Now, however, most of the big, old elms have been wiped out by Dutch elm disease. Many of them were replaced by ash, which have in turn been killed by another imported pest: the emerald ash borer. By the 1970s, writes Jones, much of America’s urban tree cover had fallen victim to “disease, development and shrinking municipal budgets”.

Thousands of miles away, in Bangkok, the main threat is construction work. After a group of residents tried in vain to save several mature trees on their lane, which were felled to make way for a car park, they formed a tree advocacy group, the Big Trees Project.

Within weeks, membership swelled to 16,000. Forestry officer at the Food and Agriculture Organisation of the United Nations (FAO), Simone Borelli tells me of similar tree advocacy groups in Malaysia, India and Central African Republic, where the capital, Bangui, has “grown out of the forest and is eating it up”.

 Elm trees line Fifth Avenue by Central Park in New York. Photograph: Alamy

 

This month will see representatives from the world’s cities convene in Quito, Ecuador, for the United Nations conference on sustainable urban development,Habitat III. An agreement called the New Urban Agenda will be launched, to address the challenges facing a growing global urban population that already accounts for over 50% of us.

The document is littered with references to green spaces being essential for mental and physical health, community building and performing urgent ecological tasks. Research has turned up fascinating evidence as to why town councils, planners and developers – in whose hands the fate of urban trees lies – should take heed.

Until recently, says Jones, city officials saw trees as “expensive ornaments”. But what is now known about the ecological services that trees provide is staggering.

Trees can cool cities by between 2C and 8C. When planted near buildings, trees can cut air conditioning use by 30%, and, according to the UN Urban Forestry office, reduce heating energy use by a further 20-50%. One large tree can absorb 150kg of carbon dioxide a year, as well as filter some of the airborne pollutants, including fine particulates.

It’s hard to put a price on how an avenue of plane trees can muffle the roar of a main road, although trees do on average increase the value of property by 20%. Perhaps money does grow on them after all.

When the New York City park department measured the economic impact of its trees, the benefits added up to $120m a year. (Compare that to the $22m annual parks department expenditure.) There were $28m worth of energy savings, $5m worth of air quality improvements and $36m of costs avoided in mitigating storm water flooding. If you look at a big tree, says Jones, “it’s intercepting 1,432 gallons of water in the course of a year.”

Use of the open source software, i-Tree, has spread all over the world (from China to the UK, via Brazil and Taiwan) to assess canopy size – ideally, cities should have 40% coverage – and calculate its economic worth. “To be able to monetise those benefits is really useful,” says Jones. “Trees are economic drivers. Everyone knows, if you look at fancy neighbourhoods, they are the ones with the most trees.” By the same token, she observes that underprivileged neighbourhoods are often also undercanopied.

Humans are drawn to trees by more than aesthetics. It can bring down cortisol levels in walkers, which means less stress. The effect on our brains is a subject that fascinates UK-based GP and public health expert William Bird.

“The parts of our brain we use change when we connect with nature,” he says. Even in lab-based studies, MRI scanning shows that when viewing urban scenes, blood flow to the amygdala – the “fight-or-flight” part of the brain – increases. Our brains view cities as hostile environments. Natural scenes, by contrast, light up the anterior cingulate and the insula, where empathy and altruism happen.

“In areas with more trees,” says Bird, “people get out more, they know their neighbours more, they have less anxiety and depression.” (Here in the UK, the annual mental health bill is around £70bn.) “Being less stressed,” he continues, “gives them more energy to be active”. But you can’t fob people off with an empty playing field, he says. “People won’t want to go there. We are still programmed as hunter gatherers who look for trees, biodiversity, water and safety.”

Research suggests people are less violent when they live near trees. One of the oft-cited examples is a study that looked at women in a Chicago housing estate. Those who lived near the trees reported less mental fatigue and less violent tendencies than those in barren areas of the same estate.

‘In areas with more trees, people get out more’: a tree-lined street in Gothenburg. Photograph: Souvid Datta for the Guardian

 

“We still know very little about the mechanisms linking trees and health,” says Geoffrey Donovan, research forester with the US Forest Service. But there are theories. One is that nature is so mentally restorative that it gives our minds a rest from the forced, direct attention that modern life and urban environments increasingly call for. It relieves mental fatigue.

A tree psychology study that particularly tickles Jones was done in Toronto bypsychology professor Marc Berman, using data sets from the national health system. “He discovered that, if you have 10 more trees on a city block, it improves health perception as much as having £10,000 more in income, or feeling seven years younger,” she says.

Perhaps one of the most striking studies on urban trees is one that showed that they reduce health inequality. In 2008, Rich Mitchell, a public health professor at the University of Glasgow, compared income deprivation and green space exposure across England and his study found “health inequalities related to income deprivation in all-cause mortality and mortality from circulatory diseases were lower in populations living in the greenest areas”.

Back at the US Forest Service, Donovan refers to trees as “a matter of life and death”. “I looked at the impact of trees on birth outcomes and found that mothers with more trees within 50m of their homes are less likely to have underweight babies,” he says. For another study, he looked at mortality rates in areas which have lost millions of trees to emerald ash borer, and identified “a corresponding increase in human mortality”.

The value we place on trees and nature is informed by childhood experience. Children growing up dislocated from nature results in, say some researchers, an “extinction of experience”. These children will ultimately understand and value nature less. “This means,” writes Bird, “that each generation will pass on less experience of the natural environment – and as policymakers and future environmentalists they will have a poorer understanding of nature and so give it less value”.

Which would not bode well for the FAO Forestry Department’s vision of “greener, happier, healthier cities”. As Jones says, “being an amateur tree appreciator, as I now am, really does transform your enjoyment of being out and about”.

 

This article was originally posted on the Guardian.

The "Climate Action Tracker" is an independent science-based assessment, which tracks the emission commitments and actions of countries. The website provides an up-to-date assessment of individual national pledges, targets and INDCs and currently implemented policy to reduce their greenhouse gas emissions.

The CAT tracks 32 countries covering around 80% of global emissions. All the biggest emitters and a representative sample of smaller emitters covering about 80% of global emissions and approximately 70% of global population.  The national actions we track are:

• Effect of current policies on emissions: The policies a government has implemented or enacted and how these are likely to affect national emission over the time period to 2030, and where possible beyond.
• Impact of pledges, targets and INDCs (link) on national emissions over the time period to 2030, and where possible beyond.
• Fair share and comparability of effort: Whether a government is doing its “fair share” compared with others towards the global effort to limit warming below 2?C. 

CAT calculates global warming consequence and emissions gaps. The Climate Action Tracker assesses the total global effort of INDCs, pledges and current policies.

Rating countries

Governments have agreed to hold warming to below 2°C. The focus of emission reduction proposals to be submitted in INDCs during 2015 is for governments to put forward their proposed contributions to a “fair sharing” of effort to move global emissions downward in the period 2020-2025-2030.

The Climate Action Tracker rates INDCs, pledges and current policies against whether they are consistent with a country's fair share effort to holding warming to below 2°C.

The CAT “Effort Sharing” assessment methodology applies state-of-the art scientific literature on how to compare the fairness of government efforts and INDC proposals against the level and timing of emission reductions needed to hold warming to below 2°C. The main focus is on the period 2020, 2025 and 2030.

Check the Individual country assessments on this list.

In September 2015, 193 world leaders agreed to 17 Global Goals for Sustainable Development. If these Goals are completed, it would mean an end to extreme poverty, inequality and climate change by 2030.

Our governments have a plan to save our planet…it’s our job to make sure they stick to it.

The Global Goals are only going to work if we fight for them and you can’t fight for your rights if you don’t know what they are. We believe the Goals are only going to be completed if we can make them famous.

[video: https://youtu.be/Mdm49_rUMgo]
 

Goal 13: Take urgent action to combat climate change and its impacts

Climate change is now affecting every country on every continent. It is disrupting national economies and affecting lives, costing people, communities and countries dearly today and even more tomorrow.

"This is not a partisan debate; it is a human one. Clean air and water, and a liveable climate are inalienable human rights. And solving this crisis is not a question of politics. It is our moral obligation.", Leonardo DiCaprio

Targets

• Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries
• Integrate climate change measures into national policies, strategies and planning
• Improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning
• Implement the commitment undertaken by developed-country parties to the United Nations Framework Convention on Climate Change to a goal of mobilizing jointly $100 billion annually by 2020 from all sources to address the needs of developing countries in the context of meaningful mitigation actions and transparency on implementation and fully operationalize the Green Climate Fund through its capitalization as soon as possible
• Promote mechanisms for raising capacity for effective climate change-related planning and management in least developed countries and small island developing States, including focusing on women, youth and local and marginalized communities

Know more about the 13 Global Goal for Sustainable Development.

The future of our Planet is in our hands. WWF's Living Planet Report 2016 shows the scale of the challenge - and what we can do about it.

Global biodiversity is declining at an alarming rate, putting the survival of other species and our own future at risk. The latest edition of WWF’s Living Planet Report brings home the enormity of the situation - and how we can start to put it right. The Living Planet Index reveals that global populations of fish, birds, mammals, amphibians and reptiles declined by 58 per cent between 1970 and 2012. We could witness a two-thirds decline in the half-century from 1970 to 2020 – unless we act now to reform our food and energy systems and meet global commitments on addressing climate change, protecting biodiversity and supporting sustainable development.

ENTERING A NEW ERA

Human activities are pushing our planet into uncharted territory. In fact, there’s strong evidence that we’ve entered a new geological epoch shaped by human actions: “the Anthropocene”. The planet’s inhabitants – Homo sapiens included – face an uncertain future.

The loss of biodiversity is just one of the warning signs of a planet in peril. The Ecological Footprint – which measures our use of goods and services generated by nature – indicates that we’re consuming as if we had 1.6 Earths at our disposal. In addition, research suggests that we’ve already crossed four of nine “Planetary Boundaries” – safe thresholds for critical Earth system processes that maintain life on the planet.

[video: https://youtu.be/VMsxHaeyzNs]

TOWARD A RESILIENT FUTURE

But if humans can change the planet so profoundly, then it’s also in our power to put things right. That will require new ways of thinking, smarter methods of producing, wiser consumption and new systems of finance and governance.

The Living Planet Report provides possible solutions – including the fundamental changes required in the global food, energy and finance systems to meet the needs of current and future generations.

INSPIRING STORIES

There are reasons for hope. All over the world there are examples of successful restoration of ecosystems, recovery of species and creation of resilient and hospitable places for wildlife and people.

Here we highlight several inspiring cases.

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Concepter Inc. is a newly established company with a 3-years old story contributing to a better nightshot amateur activities. The company made a first step forward in 2013, launching an unforgettably successful campaign on Kickstarter. Till then, Concepter has widened its product line and built a stable community of fans, supporters, professionals and backers. The energy and pace our company has given to devices like iblazr 1 and iblazr 2 is driven by a personal touch to achieve user’s satisfaction.

The iblazr family represents LED flash for smartphones, tablets and DSLR cameras. The gadget goes well beyond simply lighting up its subjects. With an App and special accessories it offers user-controlled photo quality regulation for an amateur “smartphonographer.”

With our iblazer lights we encourage people to tell their climate stories, to document nature as it is affected by climate change and to film and photograph the all important climate solutions we see enacted every day. Our gadgets are not only for photo-travelers and photography fans, but for every ordinary citizen of the Earth, who is affected by climate change and wants to build a resilient low-carbon future.

At Concepter Inc. we have chosen the least harmful technology for mass production to protect the atmosphere and environment. We aim to work only with ecologically safe and effluent-free materials.

We are exited to join the global partnership program Connect4Climate as they support young filmmakers around the world highlighting the critical stories on climate change.

The United Nations Environmental Youth Action Initiative (UNEYAI Liberia) in collaboration with the LBS Community leadership, were able to successfully implement the  Community Cleanup and Solid Waste Management (CC-SWM) Project in the LBS Community on Saturday, October 1, 2016, with over ten (10) community volunteers and some community leaders who participated in our Pre-Training and Community Cleanup exercises on October 1, 2016.

UNEYAI Liberia Country Director, Ms. Sangaye Kweegbo was able to gave an overview of UNEYAI Liberia establishment, objectives, leadership, and the organization thematic areas of work, while Mr. Thomas P. Mitchell, Program Director of UNEYAI Liberia elaborated on the organization programs that are designed, with more emphasis on the Community Cleanup and Solid Waste Management (CC-SWM) Project.

The Community Cleanup and Solid Waste Management (CC-SWM) Project is a community based environmental campaign that inspires and empowers communities from every corner to clean up and conserve their environment. The LBS Community was our first target and we hope to implement the CC-SWM Project into other affected communities

Some 65 young people from Gilgit Baltistan participated in an interactive workshop on climate change organized by United Nations Information Center (UNIC) in collaboration with Australian Aid, Connect4Climate and the Aga Khan Foundation.

[video: https://vimeo.com/185184528]

The primary purpose of the workshop was to raise awareness about climate change among the youth of Gilgit Baltistan, a region heavily affected by periodic floods, one of the effects of climate change.

This workshop was part of the Pakistani Youth for Climate Change initiative, a multidisciplinary project aimed at involving Pakistani young people in the global conversation on climate change

Several young people took the floor to share their own experiences and suggestiond for tackling the effects of climate change.

[video: https://vimeo.com/186238729]

Anusha, a 9th grade student from Sher Qilla, warned the audience about the devastating effects of climate change. She narrated how the climate has visibly changed since the time of her grandmother’s youth.

Saira Zahid from Skardu urged the participants to start acting to stop global warming and talked about glacier grafting, a local practice in Gilgit Baltistan consisting in building small glaciers as a mean to combat climate change. Mariya Akbar, from Gilgit Baltistan shared her personal experience with extreme weather conditions in Gilgit Baltistan to highlight the effects of climate change on life and livelihood. Nazish Amir from GIlgit focused on the manmade actions contributing to climate change and said: “We shouldn’t wait for miracles to happen. Why don’t we go out and plant more trees?”

Lastly, Jibran, a 9th grade student from Gilgit, explained his vision of a climate smart Gilgit Baltistan and proposed practical and easy solutions, like effective waste management.

All the participants received useful information on climate change together with sustainable and environmentally friendly bags to be used as an alternative to plastic bags.

See Photo gallery