How do we save ageing Australians from the heat? Greening our cities is a good start



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A shade tree makes a big difference to the comfort of this couple.
Nancie Lee/Shutterstock

Claudia Baldwin, University of the Sunshine Coast; Jason Byrne, University of Tasmania, and Tony Matthews, Griffith University

Heatwaves have killed more Australians than road accidents, fires, floods and all other natural disasters combined. Although recent research shows extreme cold is a worry in some parts of Australia, our hottest summer on record points to more heat-related deaths to come. The record heatwaves have highlighted the damaging effects of heat stress. Understandably, it’s becoming a major public health challenge.




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The risk of extreme heat events and the adverse impacts on older people has been extensively discussed in research. Remarkably, very little attention has been paid to the role of urban greenery in reducing heat stress for seniors.

Older people are particularly at risk of heat stress. Pre-existing medical conditions and limited mobility increase their vulnerability. Deaths of older people increase during extreme heat events.

The physical features of urban areas shape the capacity of older adults to engage in many activities when it’s hot. These include vegetation volume and coverage, thermal design, and the extent of shading in public areas and walkways. Increasing urban greenery may offer a way to improve older people’s comfort and social experience.




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Building cool cities for a hot future


Ageing adds urgency to greening

It is expected 20% of the global population will be older than 60 by 2050. The figure for Australia is even higher, at 23%. This means that by 2050 around one in four Australians will be more vulnerable to extreme heat.

Older people are more vulnerable to heat stress.
PorporLing/Shutterstock

Climate change may make the problem worse by fuelling even more extreme heat events.

Planning our urban centres to meet the needs of a rapidly ageing population is a matter of urgency. Urban greening to reduce their vulnerability to heat stress should be central to this agenda. It can also improve people’s quality of life, reduce social isolation and loneliness, and ease the burden on health systems.

An important task is matching the design of communities with the needs of an ageing population. Where older adults live and the quality of their local areas strongly influence their lived experiences. Yet recent research found the experiences of seniors were often not accounted for in research on neighbourhood design.




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What about aged care?

People face choices about where they live as they age. The common choices are to “age in place” or to move into aged care.

Ageing in place includes living in one’s own home or co-habiting with relatives or friends. Around 90% of Australian seniors choose this option, with the remainder opting for aged-care facilities.

If one in ten Australian seniors live in aged-care facilities, it is clear these should be designed to minimise heat stress. This isn’t just good for residents; it may also benefit operators by lowering health-care and electricity costs.

While these facilities are purpose-built for older people, many in Australia were built well over a decade ago, when heat stress was not such a large concern. Many more facilities are being built now and will be into the future. Yet it is uncertain whether they are being actively designed to reduce the impacts of heat.




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Australian cities are lagging behind in greening up their buildings


What has our research found?

We recently conducted a focus group to investigate this issue. Participants were senior managers from four large corporate providers of aged care in Australia. We investigated if and how providers try to minimise heat stress through design. We also sought to understand the rationales used to support these design approaches.

Several participants reported on refurbishments that they expect will have cooling effects. Cited design approaches included green roofs and walls, as well as sensory gardens. Other expected benefits included reducing anxiety and improving the mental health of residents.

The fact that single design interventions could produce multiple benefits improved the potential for corporate buy-in. Participants expected that increasing green space and green cover would give their facilities a competitive advantage by attracting more clients and providing a better working environment for staff.

Participants also reported on challenges of including greening in their projects. For example, the benefits of trees were weighed against concerns about roots disrupting footpaths and becoming trip hazards. Species selection was another concern, with fears that inappropriate plants could die and undermine support for greening programs.

Our research suggests that more can be done to make cities hospitable for older people, especially during extreme heat. Urban greening is a start. Encouraging aged-care providers to adopt green infrastructure will have benefits. But we should also consider reforms to planning systems and urban design to better protect older people who choose to age in place.




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If planners understand it’s cool to green cities, what’s stopping them?


The Conversation


Claudia Baldwin, Associate Professor, Urban Design and Town Planning, Sustainability Research Centre, University of the Sunshine Coast; Jason Byrne, Professor of Human Geography and Planning, University of Tasmania, and Tony Matthews, Senior Lecturer in Urban and Environmental Planning, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Australian cities are lagging behind in greening up their buildings


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Green rooftops give a backyard feel to smaller housing units in Sydney
Author Provided , Author provided

Sara Wilkinson, University of Technology Sydney; Paul J Brown, University of Technology Sydney, and Sumita Ghosh, University of Technology Sydney

Covering roofs and walls of buildings with vegetation is a good way of reducing greenhouse gas emissions. And these green roofs and walls make cities look nicer. Toronto’s central business district adopted a policy of establishing green roofs on around half of all city buildings in 2009. Research shows this could reduce maximum city temperatures by up to 5℃.

We spent the past 12 months analysing the case for more greenery on Australian city buildings, drawing on international comparisons. We’ve shown that a mandatory policy, coupled with incentives to encourage new and retrofitted green roofs and walls, will provide environmental, social and business benefits.




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Green roofs and walls – a growth area in urban design


These include improved air quality, energy conservation and reductions in stormwater run-off from buildings, which would decrease flash flooding. Green roofs and walls also become new habitats for biodiversity and can be pleasant spaces for social interaction in dense urban areas.

We found numerous studies confirming that greenery on inner-city buildings reduces the urban heat island effect, which is when city centres are hotter than surrounding suburban and outer-urban areas.

Green roofs are great social spaces.
Author provided, Author provided

What other countries are doing

We examined international case studies of cities embracing green roofs and walls to review policy frameworks which could be suitable for Australia. A range of measures and policies exist and vary depending on building types (buildings need specific features to host vegetation) and the degree to which policies can be enforced.

Singapore is leading in this area. It markets itself as a “garden city” to attract investment, visitors and commerce. Green roofs and walls are a vital and visual manifestation of this policy.

Green walls are aesthetically pleasing.
Author provided

Greenery is ingrained in Singapore’s development sector and is boosted by incentives, grants, awards, certification schemes and government-led development. Through this voluntary-heavy (yet supported) effort, Singapore increased its number of green roofs and spaces nine-fold between 2006 and 2016.

Rotterdam’s efforts weren’t as extensive as Singapore’s, but the city more than doubled its green roof area from 2012-2017 through incentives, grants, tax benefits and demonstration projects.

London increased its total green-roof area more than four-fold from 2005-2016. This was partially achieved through a biodiversity action plan.

And Toronto has the second-largest area of green roofs of the four cities we studied. This has been delivered through a mandatory policy, introduced in 2009, that requires all new developments with roofs of 2,000m² or more to install green roofs.

The case in Australia

We modelled what could be delivered in the City of Sydney and the City of Melbourne based on the measures taken in Singapore (which is voluntary-heavy), London (voluntary-light), Rotterdam (voluntary-medium) and Toronto (mandatory).

We combined this with data on actual green building projects in 2017 in Sydney and Melbourne to show the potential increase of projects in each city based on the four policies.

In the Sydney local government area, 123 green roof and wall projects were under way in 2016. The below table uses this base to estimate what the numbers of such projects would be for three time periods, based on the policies in the four scenarios modelled.

https://datawrapper.dwcdn.net/7ff2z/3/

In the Melbourne local government area, 28 green roof and wall projects were under way in 2016. The table below shows how these could increase based on policies of the four case studies modelled.

https://datawrapper.dwcdn.net/s2Efy/1/

How Australia can get on board

Sydney and Melbourne have green roof and green wall policies aligned with their 2030 and 2040 sustainability targets, launched in 2012 and 2015 respectively. Sydney has the Green Roofs and Walls Policy Implementation Plan, while Melbourne has the Growing Green Guide 2014.

These policies appear most aligned with the voluntary-light approach adopted in London. Sydney had a 23% increase in green roofs since its policy launch, although this was from a very low starting point. Melbourne also reports an increase in green roofs and walls, though the amount of uptake isn’t publicly available.

There are, of course, barriers to greening up buildings. These include costs as well as lack of experience in the industry, especially in terms of construction and management. Professional capacity for green roofs is still in a developing phase and further training and skill development are needed.

Green wall adds vegetation to an aged care home in Sydney.

Around 87% of the building stock Australia will have in 2050 is already here, and a large proportion of existing buildings could be retrofitted. We recommend a voluntary approach using a mix of initiatives for building owners, such as tax benefits and credits in green building tools.




Read more:
If planners understand it’s cool to green cities, what’s stopping them?


Focusing on new buildings is likely to lead to more modest growth rates in the short to medium term, relative to alternative approaches such as retrofitting. The annual growth rate of new stock is around 1-3%, which means that policies focusing on new stock will have a substantial impact over the long term.

However, in the short to medium term, a retrofit policy would have greater impact given the numbers of existing buildings suitable for this.

The ConversationLocal government areas can also promote the evidence showing the lift in property values in areas with more green infrastructure – in some instances up to 15%. This should encourage voluntary uptake.

Sara Wilkinson, Associate Professor, School of the Built Environment, University of Technology Sydney; Paul J Brown, Senior Lecturer – Creative Intelligence | Faculty of Transdisciplinary Innovation & Senior Lecturer – Accounting | UTS Business School, University of Technology Sydney, and Sumita Ghosh, Senior Lecturer, School of the Built Environment, University of Technology Sydney

This article was originally published on The Conversation. Read the original article.

Rising carbon dioxide is greening the Earth – but it’s not all good news


Pep Canadell, CSIRO and Yingping Wang, CSIRO

Dried lake beds, failed crops, flattened trees: when we think of global warming we often think of the impacts of droughts and extreme weather. While there is truth in this image, a rather different picture is emerging.

In a paper published in Nature Climate Change, we show that the Earth has been getting greener over the past 30 years. As much as half of all vegetated land is greener today, and remarkably, only 4% of land has become browner.

Our research shows this change has been driven by human activities, particularly the rising concentration of carbon dioxide (CO₂) in the atmosphere. This is perhaps the strongest evidence yet of how people have become a major force in the Earth’s functioning.

We are indeed in a new age, the Anthropocene.

How do you measure green?

Plants play a vital role in maintaining Earth as a habitable place, not least through absorbing CO₂. We wanted to know how people are affecting this ability.

To do this, we needed to know how much plants are growing. We couldn’t possibly measure all the plants on Earth so we used satellites observations to measure light reflected and absorbed from the Earth’s surface. This is a good indicator of leaf area, and therefore how plants are growing.

We found consistent trends in greening across Australia, central Africa, the Amazon Basin, southeast United States, and Europe. We found browning trends in northwest North America and central South America.

Updated figure to 2015. Source: http://sites.bu.edu/cliveg/files/2016/04/LAI-Change.png

We then used models to figure out what was driving the trends in different regions.

A CO₂-richer world

Plants need CO₂ to grow through photosynthesis. We found that the biggest factor in driving the global greening trend is the fertilisation effect of rising atmospheric CO₂ due to human activity (atmospheric concentration grew by 46 parts per million during the period studied).

This effect is well known and has been used in agricultural production for decades to achieve larger and faster yields in greenhouses.

In the tropics, the CO₂ fertilisation effect led to faster growth in leaf area than in most other vegetation types, and made this effect the overwhelming driver of greening there.

A warmer world

Climate change is also playing a part in driving the overall greening trend, although not as much as CO₂ fertilisation.

But at a regional scale, climate change, and particularly increasing temperature, is a dominant factor in northern high latitudes and the Tibetan Plateau, driving increased photosynthesis and lengthening the growing season.

Greening of the Sahel and South Africa is primarily driven by increased rainfall, while Australia shows consistent greening across the north of the continent, with some areas of browning in interior arid regions and the Southeast. The central part of South America also shows consistent browning.

A nitrogen-richer world

We know that heavy use of chemical nitrogen fertilisers leads to pollution of waterways and excess nitrogen which leads to declining plant growth. In fact, our analysis attributes small browning trends in North America and Europe to a long-term cumulative excess nitrogen in soils.

But, by and large, nitrogen is a driver of greening. For most plants, particularly in the temperate and boreal regions of the Northern Hemisphere, there is not enough nitrogen in soils. Overall, increasing nitrogen in soils has a positive effect on greening, similar to that of climate change.

A more intensively managed world

The final set of drivers of the global greening trend relates to changes in land cover and land management. Land management includes forestry, grazing, and the way cropland is becoming more intensively managed with multiple crops per year, increasing use of fertilisers and irrigation.

All of this affects the intensity and time the land surface is green.

Perhaps surprisingly, felled forests don’t show as getting browner, because they are typically replaced by pastures and crops, although this change has profound effects on ecosystems.

The greening trends in southeast China and the southeastern United States are clearly dominated by land cover and management changes, both regions having intensive cropping areas and also reforestation.

Although this management effect has the smallest impact on the greening trend presented in this study, the models we used are not suitable enough to assess the influence of human management globally.

The fact that people are making parts of the world greener and browner, and the world greener overall, constitutes some of the most compelling evidence of human domination of planet Earth. And it could be good news: a greening world is associated with more positive outcomes for society than a browning one.

For instance, a greener world is consistent with, although it does not fully explain, the fact that land plants have been removing more CO₂ from the atmosphere, therefore slowing down the pace of global warming.

But don’t get your hopes up. We don’t know how far into the future the greening trend will continue as the CO₂ concentration ultimately peaks while delayed global warming continues for decades after. Regardless, it is clear that the benefits of a greening Earth fall well short compared to the estimated negative impacts of extreme weather events (such as droughts, heat waves, and floods), sea level rise, and ocean acidification.

Humans have shown their capacity to (inadvertently) affect the word’s entire biosphere, it is now time to (advertently) use this knowledge to mitigate climate change and ameliorate its impacts.

The Conversation

Pep Canadell, CSIRO Scientist, and Executive Director of the Global Carbon Project, CSIRO and Yingping Wang, Chief research scientist, CSIRO

This article was originally published on The Conversation. Read the original article.