In cities across the country, the promotion of higher residential densities in certain areas has become an orthodox part of urban planning. Consolidation, as opposed to sprawl, is seen as a way to accommodate the apparent inevitability of larger cities in a more sustainable, economical, and healthy way.
One of the other great touted benefits of high-density living is that it frees people from cars and gets them active. But is there a direct link between higher-density neighbourhoods and health?Heart health and density
We do know there is a relationship between the built environment and behaviours beneficial to health. Physical activity is one such behaviour, and when done regularly can reduce cardiovascular disease-related deaths by up to 35%.
Recognising this link, the Heart Foundation has long advocated for walkable neighbourhoods with mixed land use and densities, connected streets, quality open spaces, and access to public transport.
It takes many factors to create a “walkable neighbourhood”. But how does residential density specifically influence opportunities for physical activity? Our research concludes that the effect of density on active living is incredibly complex. To unpick it, let’s look at how urban planning more generally can influence physical activity.Good planning and active people
One way to influence activity is to encourage people to use “active transport”, including walking, cycling, and public transport. Good planning can help make these options safe, comfortable and accessible.
Another key aspect is distance. Grid-like street networks with short blocks can make travel routes more direct, but if destinations, like work and home, are too far apart, most people won’t walk or ride between them.
Finally, we need to make sure that people have somewhere to walk and cycle to, and places to engage in more structured physical activity. This normally means mixed-use zoning so that residential areas are interspersed with shops, services, schools and green open spaces.
All this means that higher housing density alone will not make people more or less active. There is, however, certainly a relationship between higher-density built environments and physical activity.
On the surface, a certain amount of density might be quite good for you. This is related to the concept of “critical mass” – the aspects of the built environment that can encourage healthier habits often require people, and sometimes a lot of people, to make them viable. Public transport networks, walking and cycling infrastructure, well-maintained green spaces and small neighbourhood shopping centres all need people to make them work. Of course, they are also easier to provide when less land is taken up by homes.
But it’s not quite as simple as that. While living in low-density areas is linked to lower levels of physical activity, there is also evidence that too much density is associated with negative health outcomes, particularly in terms of mental health. Higher-density can breed stress and social isolation, often associated with depression and anxiety disorders.
Badly constructed or poorly located higher-density housing can also cause problems through poor ventilation and insulation, lack of sunlight, insufficient public and private open space, and exposure to pollutants or intrusive noise.
These issues can lead to respiratory health problems, as well as isolation, fear of crime, and community dislocation. They can very quickly erode or prevent the development of the healthy aspects of higher-density living, including regular physical activity.So what makes density work?
There are potential health benefits associated with higher-density living, but these benefits depend on several other variables. A review commissioned by the Heart Foundation identified three key factors.
First is the quality of infrastructure in the surrounding neighbourhood and region. Higher-density housing needs to be situated among public transport networks, jobs, schools, shops, services, open space and active transport infrastructure.
Second is the quality of construction and management of the homes themselves. It has been far too easy in Australia to provide higher-density housing that is poorly sited, badly built, and ineptly managed. It is also far too easy to forget that density means diversity – it includes detached and semi-detached housing, townhouses, low- and mid-rise apartment buildings, as well as high-rise.
Third is the social and cultural make-up of the community that is living in higher-density places. We mentioned that healthy built environments need people to make them work, and people are sometimes frustratingly brilliant in their diversity. Indeed, success depends on the capacity of new and existing communities to adapt to different ways of living, working, travelling and socialising. This makes it difficult to make realistic generalisations about the impact of density on human health.
What we do know is that vulnerable populations will be more susceptible to any negative impacts of higher density.
There is evidence, for example, that high-rise living in particular is associated with lower levels of satisfaction and a poorer sense of community in older adults. The needs of children in higher-density housing also deserve special attention.
The issue is a complex one. There are potential health benefits on offer from urban densification, but also the possibility of unintended consequences that can quickly undermine them. As Australia’s cities become increasingly crowded, we will need to watch carefully to know whether we are getting it right.
This article was co-authored by Michelle Daley, Senior Manager, Active Living, at the National Heart Foundation of Australia.
Jennifer Kent does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.
The prince says time is running out and warns business leaders must address chasm between principles at home and at work
Prince Charles has launched a blistering attack on companies that are actively seeking to delay progress on preventing runaway climate change. Highlighting the need for a radical shift in the way the economy is run, he said that over the past decade he has been met by either indifference from mainstream business leaders and economists, or outright opposition.
Pointing out that science had proved beyond doubt the terrifying impacts of inaction, he called on executives to collapse the chasm between how they acted at home and what they were prepared to do in the office.Continue reading...
If the highest calibre of young people become farmers it will improve food security and help solve the unemployment crisis. Can tech make farming cool?
As farmers age around the globe – I estimate that the average age is 55 – we need to make sure that young people see the food system as a viable career option. These farmers are the future of food. They can help to mitigate and potentially reverse climate change, curb unemployment and provide more nutrient-dense crops to the world.
Unfortunately, farming is usually seen as a last-resort profession. Rural youth migrate to cities in search of employment, and lack of infrastructure and education leads to poverty and malnutrition. But investing in young agricultural leaders has the power to transform the entire food system. Government leaders, businesses, and farmers groups need to make agriculture something youth want to do, not something they feel forced to do.
Related: Unlocking the power of women farmersContinue reading...
Climate change science has been a non-starter in the Queensland election, despite the state being on the front line of impacts
What does the Queensland election campaign and Nobel Prize winner the late Professor Sherwood Rowland have in common?
Nothing. And also everything.
What is the use of having developed a science well enough to make predictions if, in the end, all we’re willing to do is stand around and wait for them to come true?
Council noted the Deputy Premier’s concerns, but indicated the inclusion of climate change factors, including sea level rise, based on the best scientific and technical information available to the Council was necessary in order to protect the Council against legal liability.
I direct council to amend its draft planning scheme to remove any assumption about a theoretical projected sea level rise due to climate change from all an any provision of the scheme, including strategic framework, zones and precincts, overlay assessment tables, codes and policies.Continue reading...
Need a heartwarming story? Look no further.
Adrian Manygoats is on a mission to help Navajo communities, many of which live under the poverty line and lack electricity. So she’s installing rooftop solar panels — for free. For more on this inspiring project, watch the video below.
Courtesy of NationSwell
The federal government’s new “Technical Advisory Forum” on weather data, announced by parliamentary environment secretary Bob Baldwin last week, will “review and provide advice on Australia’s official temperature data set”. This data set, known as ACORN-SAT and maintained by the Bureau of Meteorology, is the primary record used for monitoring temperature trends around the country.
Although the advisory forum’s detailed terms of reference have not been released, it seems clear that when the panel meets in March it will not be tasked with delivering the comprehensive audit demanded by some of the Bureau’s prominent critics, such as the Prime Minister’s business adviser Maurice Newman.
That’s fair enough, considering that a comprehensive, independent and international peer review was carried out as recently as 2011 and concluded that the Bureau’s practices and data meet the world’s best standards.
Instead, the announcement seems to be acting on a recommendation from the 2011 review (see recommendation E4, page 14), which suggests that a technical advisory group be established so that “respected external scientists, statisticians and stakeholders [can] provide an opportunity for external comment on the further development of the ACORN-SAT system”.
The new panel features eight scientists, with a variety of backgrounds but based mostly in statistics, chaired by University of New South Wales statistician Ron Sandland. What advice are they likely to offer?What will be reviewed?
While we do not yet know in any detail, with all this statistical expertise we can perhaps assume that one of the main areas for review will be the statistical practices applied to the ACORN-SAT data. In particular, it is likely that the practices around data homogenisation will be covered.
This blending, merging and/or adjusting of weather data is a necessary step in the generation of uniform, continuous climate records of the highest quality.
As described in a previous Conversation article, raw climate data can sometimes be patchy over time, and often contains artificial jumps and/or trends that are due to non-climate factors such as changes in observing practices, the movement of stations, or changes to the surroundings at the instrument’s location (for instance because of urban development).
For changes to our climate to be effectively monitored, continuous records must be generated that show only those influences associated with the climate. To do this, climate scientists use statistical adjustments that are based on cross-comparisons with any information about what could have caused any artificial signals, or comparisons with other nearby instruments.
Given the expertise of those listed as members of the Technical Advisory Forum, we might speculate that it is these statistical adjustments that are likely to be examined in more detail by the advisory group.Fact-checking is a must in science
The “fact-checking” of scientific data is a necessary part of the scientific process. Thorough, objective and critical evaluation of scientific methods and findings must be undertaken to ensure confidence in scientific findings.
Such tenets underpin the process of peer-review in scientific journals. Notionally, all studies are examined with a fine-toothed comb by a series of experts to ensure they are robust before they are published (although there is recent evidence that this comb is, unfortunately, not always as rigorous as we might expect).
The same standards must apply for any form of scientific inquiry, including those areas that have become highly politicised and polarised, such as climate science.
An objective external review might also provide information that can be highly constructive and encourage scientific advancement, as well as checking the existing work. For example, a panel of experts in statistical theory and application might be able to provide information on new statistical techniques that could be applied to the data. Any scientist would welcome such input, as it will help to advance scientific knowledge.Does Australia’s temperature record need another review?
This will not be the first time that official temperature records, either in Australia or globally, have been reviewed and their statistical techniques critiqued.
One of the most comprehensive reviews of global surface temperature records was the Berkley Earth project, which also included a section on Australia’s data. The review concluded that the evidence of warming in surface temperature records is robust.
Given the previous reviews, it is worth asking whether yet another review is really necessary. There are philosophical arguments as to whether or not it is strictly necessary, but in my opinion it’s worth doing anyway.
On one hand, commissioning review after review does rather give an impression that time and resources are being wasted, especially if the answer is fundamentally the same every time. It is my opinion that any recommendations implemented from the advisory group will not change the key features of Australia’s official temperature record, which shows that the country has warmed by around 0.9C since 1910, and that 7 of the 10 hottest years have happened since 2002.
But on the other hand, such reviews have the capacity to lead to more transparent and reproducible science. This is fundamental to the scientific method and so, in my opinion, should always be welcomed.
Editor’s note: Ailie will be answering questions between 3:30 and 4:30pm AEDT on Wednesday January 28. You can ask your questions about the article in the comments below.
Ailie Gallant receives funding from the Australian Research Council.
An article in The Australian today has once again raised the question of why scientists, in trying to estimate how the global and regional surface temperatures of Earth may have changed over the past century or so, “adjust” the raw temperature data.
It is important to note, first off, that no data have been “altered” or destroyed in this process – all the raw data remain available for investigation by anyone who has the inclination (as I’ll show below).
But this process can lead to large adjustments to the raw data, and in at least some instances the adjusted data can suggest long-term warming even when the raw data indicate cooling.
This appears to have happened at the Paraguay stations mentioned in the article – the raw temperature recordings suggest cooling over decades, whereas warming appears after the raw data have been adjusted by NASA and NOAA.
The figure below shows this at one station in Paraguay. I have obtained the data from this station (raw and adjusted) from Berkeley Earth, an independent group who have, quite separately from NASA and NOAA, checked global temperature data for these so-called “inhomogeneities” and adjusted the raw data themselves.
Their results provide an independent check for the NASA and NOAA groups doing this adjustment. The raw data (blue line) at this station suggest cooling, whereas the “adjusted” data (pink line) indicate warming.
Berkeley Earth, Author providedThe problem with thermometers
So why do scientists “adjust” the raw data – why don’t they simply accept that the raw data are the best estimate of how the temperature has changed over decades?
The underlying problem is that whether or not a specific thermometer reading is a good estimate of the air temperature depends on how the thermometer is exposed.
Take a thermometer and attach it to a wall, and then compare the temperature you read from that thermometer with the reading from an identical thermometer in a modern Stevenson Screen located nearby.
This shows the thermometer screens at the Adelaide Observatory in 1888. Charles Todd established a very long experiment (it ran well into the 20th century) to compare temperature observations in the three different exposures illustrated here. His data show that the summer daytime temperatures measured in the typical 19th century thermometer exposure, the open stand shown on the right, were biased warm compared with the typical 20th century exposure in the Stevenson Screen shown on the left. So simply comparing the raw data from the 19th century with data from the 20th century would be misleading. Author provided
On a warm summer day the thermometer on the wall will usually record higher temperatures than the one in the Stevenson Screen. As well, any trees around the observing site, or buildings or roads or car parks, as well as many other factors, can all affect the recorded temperature.
Because nearly all long-term records of temperature anywhere in the world have been affected by such factors, for instance as a rural station or airport gets surrounded by suburbs and roads, the scientific thing to do is to make sure you take these factors into account when trying to get a picture of how the world may have warmed.How to adjust data scientifically
It would be nice if we had a compete record of all the changes to all the temperature recording sites around the world, listing in forensic detail when and where stations were moved (even a few metres can make a difference), when trees around the site were planted or removed, when car parks nearby were built, and all the buildings for tens of metres around the site.
And we would need all these details stretching back over many decades.
Unfortunately, no station exists with such comprehensive information for the last century or so. But even if these “metadata” did exist, we could not just use the raw data at a single station alone to work out how much to adjust the raw data for changes in exposure and location.
So scientists identify other “comparison” stations (as many as they can find) with which to compare the raw data at the “target” station (such as the station in the graph from Paraguay). These comparison stations are selected because their temperature variations from year-to-year generally track the changes at the “target” station.
If, however, the target station temperatures change suddenly and that change is not matched by similar changes in all the comparison stations, it is reasonable to conclude that something has happened to corrupt the raw data at the target station. The relationship between temperatures at the target and comparison stations is then used to adjust the raw data at the target station.
The details of the way this adjustment process is done varies between the groups who do this. The result of the adjustments made by Berkeley Earth for a station in Paraguay is shown in the figure above.
Both the raw and adjusted data show warming over the past forty or so years, but before the mid-1960s the data are quite different. Even looking at the raw data alone, a scientist would worry that some change in exposure has corrupted the data, because of the sudden large drop in temperature.
But the Berkeley Earth scientists have objectively adjusted for this drop, through their comparisons with other stations in the region. Their adjustments remove the sudden drop in the mid-1960s, and indicate that temperatures in the region have been warming for more than the 40 years shown by the raw data.Do it yourself
I encourage anyone who worries about the sort of adjustments made by NASA or NOAA, or in Australia by the Bureau of Meteorology, to go to the Berkeley Earth website, look at their independent results, and perhaps even do some calculations themselves to check what these other groups have done.
But don’t just think that the raw data will tell you much more than that the way the thermometer has been exposed has changed, or a car park has been built nearby, or a suburb now surrounds what once was a rural station.
You need to do the science and adjust for these corrupting factors, if you really want to work out how global and regional temperatures have changed. I’ve never been to Paraguay and I know almost nothing about the station whose data are in the graphs above. But scientists around the world have made these data available so we can do this work from our desktops.
I think this is great fun, but then I’m a nerdy meteorologist, so I would think that, wouldn’t I?
Neville Nicholls in the 1990s initiated and led the efforts by the Bureau of Meteorology to adjust raw meteorological observations to reduce the effect of changes of exposure etc., to build a credible picture of how Australia's climate has been changing. He is a member of the National Council of the Australian Meteorological and Oceanographic Society.
We can fly, drive and prosper while avoiding dangerous global warming – but only if billions remain in poverty and huge changes are made in areas such as energy and agriculture, new analysis from Decc’s Global Calculator shows
The world can enjoy higher standards of living and more travel, while drastically cutting emissions to avoid dangerous climate change – but only with sweeping changes to our infrastructure, the natural world and agriculture, a new analysis has found.
The UK government analysis also assumes that billions of people will remain in dire poverty at mid-century, despite efforts to lift them to greater prosperity, as the population rises to an estimated nine billion people.Continue reading...
The Carleton College divestment movement is on fire!
Northfield, MN – Carleton is a liberal arts college of 2,000 students in southern Minnesota. Its progressive student body has long been active in environmental and social justice is
This week a faculty letter urging divestment, signed (as of this writing) by 69 professors, was sent to the President and Board of Trustees. The signers represent about 25% of the Carleton faculty. Click here to see the letter in its entirety. Here are a few choice quotes:
“We believe it is wrong for Carleton to continue to profit from its investment in fossil fuel companies. Inadvertently supporting such a destructive industry is inconsistent with our core values of sustainability and responsible citizenry.”
“The dimensions of the current crisis are extraordinary, and merit bold action. We simply cannot take a ‘business as usual’ approach.”
“Divestment is a singular teaching moment to show that principles should stand before profits.”
A student petition has gathered over 500 student signatures, and over 300 alumni have signed the alumni petition. At the end of Fall term, the Carleton Student Association senate voted 23-0 for a resolution encouraging the College to “divest from stocks of the top 200 fossil fuel companies within the next five years.”
Students, staff, alumni, and community members also gave a compelling presentation at a town-hall meeting last term, and to the college’s Responsible Investment Committee this term. The students’ goal is to make divestment the watchword on campus this year, with plans to raise the issue at all possible public venues.
Students are also reaching out to other groups on campus to raise social justice issues, which are intimately related to the issue of climate change. For instance the CJC has urged students to support and attend the Black Lives Matter and anti-racism protests in Minneapolis and St. Paul, as well as a recent campus wide “dialogue” on racial justice.
Ideas are being circulated for a bold and exciting participation in Global Divestment Day next month. Also, a faculty initiated reading group has been proposed, which would include students and staff studying Naomi Klein’s “This Changes Everything” during Spring term.
With Board of Trustees meetings scheduled for February and May this year, there is much to do, but the Carleton community is energized and optimistic of what lies ahead on campus this year!
– Bob Dobrow and Trish Ferrett
Carleton College Faculty Members