Welcome to our Q&A section for The ‘Thrivability Matters’ webinar series. The webinar is an online gathering held on the third Tuesday of every month where invited guests present science-based sustainability learnings and share their expertise and knowledge. In this section, you will find the questions presented to the speakers and the answers they provided for the SDG11: September 2022 webinar. There is also a recording of the webinar’s Q&A available here.
Emeritus Professor John Trinder
Q: Does retrofitting old houses in larger cities help them become more sustainable, compared to buildings made with recycled materials in lands designated for housing?
A: One issue is the extension of urban areas beyond those already being used for housing. If retrofitting of old houses in large cities can maintain the existing footprint of the city, it would not encroach on neighbouring green spaces and therefore is less likely to reduce the ecosystem services that are currently available in the city. Expanding the city into neighbouring green spaces may reduce the available ecosystems eg food supply, which could impact on the well-being of the inhabitants of the city.
Q: “CLIMATE RISK MAP OF AUSTRALIA ” is a fascinating research and no doubt a mountain of work and research has gone into this. The message that the Climate council wants to get across is compelling, and I suspect you have some equally compelling headline messages. I.e. Wuhan is comparable to Western Sydney for degradation of our background ecosystem, is this your message? For example in Brisbane lots of suburbs are predicted to be unable to get their property insured by the 2032 Olympics.
A: The message is that increases in urban areas that fragment green spaces and/or use green spaces for buildings rather than food production, for example, which is a component of ecosystem services, will reduce the ability of the area to feed itself. Thus, the well-being of the inhabitants would be reduced.
Q: I couldn’t understand why resolution and ecosystems matter. What is the highest resolution these days
A: The highest resolution of current satellite data is 30 cm, but this may be improved in future. As well, it can be improved by additional processing. Airborne and drone data can have resolutions as small as 1 or 2 cm. The advantage of higher resolution data is that it shows more details on the ground. Hence in future it will be possible to assess even more information about ecosystem services, such as the impact of fragmentation on biodiversity, the characteristics of drainage patterns in urban areas, the types of hard surfaces used in urban areas and their impact on run-off and the water table. Assessing ecosystems matter because humans depend on ecosystem services on their wellbeing. If ecosystem services are diminished then that will impact on human wellbeing, such as food, fibre, green spaces and the air we breathe.
Q: Us in the Ocean Community are grappling with 30×30. How many urban conurbations have already achieved or are likely to achieve 3-30-300?
A: I need some units attached to the numbers. If you are referring to metres, then many urban areas are mapped at resolutions of the order of cm. That is fundamental to mapping urban areas given the diversity and density of details in these areas.
Q: On the subject of Scale: The Universal Laws of Life and Death in Organisms, Cities and Companies, a Book by Geoffrey West. In this the author says that as the population increases in cities the number of gas stations, supermarkets, fire stations, police stations and the like has not increased after a certain point, so there are benefits of economies of scale as cities grow larger. What are your thoughts regarding this
A: I am not aware of these statistics, but as populations grow, there will be increases in demand for ecosystem services, comprising food, fibre, green spaces, quality of air to breathe and many other services. Some authors have written that if the world’s population achieves the same standard of living as the affluent populations, then global material consumption will grow by 3 to 5 times current levels. As well, in the past 500 years, it has been estimated that technology gains have increased environmental impacts by 1.5 times, rather than reduce their impacts. Therefore, planet is at a critical stage in the consumption of resources.
Q: “The larger the city, the faster the people walk” is a statement by Geoffrey West he adds by saying that wages increase as the population increases in a city and infrastructure requirements reduce. So the returns of staying in a city are greater for an individual. Do these ideas justify rapid urbanisation in Emerging economies?
A: I am not disputing that there are economies of scale. However, see my previous comment. More people require more ecosystem services for their well-being.
Q: We are having a lot more weather extremities. How does this impact populations who are relocating to improve their situation?
A: This is a complex issue, but my view is that one of the reasons for the impacts of climate change is the rapid increase in world population in the past 50 years or so. More people emit more CO2. If populations are relocating to avoid weather extremes, then this will also impact on the ecosystem services (ES) required in the area into which they have relocated. If the ES are already under pressure and people are already consuming more ES than are available, ie demand for ES is greater than supply, then the relocated population will make an even greater demand on ES and hence cause the area to be even more unsustainable. If the supply and demand in the area are in equilibrium before the new population arrives, the addition population may make additional demands on the ES and hence cause it to become unsustainable. Only in circumstances where the supply of ES is greater than demand for ES would it be suitable for the relocated population to occupy that region.
In an ideal world, a country or region would only allow relocated populations into new areas where it has been proved that supply of ES is greater than demand. Societies are not ready or able to make such decisions, but first it is essential for countries and regions to assess their supply and demand for ES and determine areas that are operating unsustainably or sustainably. In a minor way this is happening in some countries. Administrators in Europe and US have been asked to assess how new developments will impact on ES. This is a start, but a lot must be learned for the future use of demand and supply of ES for determining whether areas are sustainable.
Q: What can you say about Canberra last year being judged as the most livable city? Based on what criteria?
A: I don’t know how this was determined. I do know that Canberra is taking major steps to become carbon neutral. This is certainly a major step forward to becoming sustainable.
Laura Puttkamer
Q: Residential homes have approximately 30% of CO2 emissions?
A: Globally, residential properties account for 17 to 21% of CO2 emissions related to energy.
Q: Hi Laura, I’m from Colombo, Sri Lanka. It is a city that is built on former wetlands and is surrounded by biodiverse wetlands. Because of this reason, we see interesting wildlife like fish, cats, crocodiles, cranes and sometimes porcupines. One of the reasons for the latter to arrive in the suburbs is because of increasing urban sprawl in the outer parts of Colombo. My city is not the best place to live during monsoon floods (May-July) as the city can get flooded very easily. Construction of new artificial wetlands and rain gardens with permeable soils have dampened the flooding issues however the same cannot be said for the other major cities in Sri Lanka. Individuals move based on better economic returns. How could this move be changed?
A: I think that it will be key for the other cities to learn from Colombo, but they will also need funding. Paris has made good experiences with participatory budgeting and allowing citizens to determine what to fund. This could influence where individuals move.
Q: Laura mentioned African cities briefly as being highly impacted by climate change effects. Can African cities ever attain sustainability based on climate change as well as the economic, social and political challenges confronting African cities?
A: I can’t answer this, but the African Centre for Cities has many interesting events and publications on this topic: https://www.africancentreforcities.net/
Q: Us in the Ocean Community are grappling with 30×30. How many urban conurbations have already achieved or are likely to achieve 3-30-300?
A: I don’t have any information on this, but you could research here: https://nbsi.eu/the-3-30-300-rule/
Q: On the subject of Scale: The Universal Laws of Life and Death in Organisms, Cities and Companies, a Book by Geoffrey West. In this the author says that as the population increases in cities the number of gas stations, supermarkets, fire stations, police stations and the like has not increased after a certain point, so there are benefits of economies of scale as cities grow larger. What are your thoughts regarding this?
“The larger the city, the faster the people walk” is a statement by Geoffrey West he adds by saying that wages increase as the population increases in a city and infrastructure requirements reduce. So the returns of staying in a city are greater for an individual. Do these ideas justify rapid urbanisation in Emerging economies?
A: I would have to read the book to answer questions above. This is not my topic of expertise.
Q: We are having a lot more weather extremities. How does this impact populations who are relocating to improve their situation?
A: In many countries, those moving to cities and looking for work are forced to live in cheap accommodation, which is often located on dangerous land in terms of potential floods or landslides.
Q: What can you say about Canberra last year being judged as the most livable city? Based on what criteria?
A: There are different indices for liveable cities. Canberra has a low pollution level, is very clean, has smart elements, and is one of the world’s most innovative cities, all of which contributes to this judgment. Read more here: https://www.canberratimes.com.au/story/7449726/new-research-says-canberra-is-one-the-best-cities-in-the-world/
