Greater Melbourne contains 31 municipalities, in an affluent multi-cultural metropolis, doubling in size in 30 years.
Large suburban-peri-urban areas are scattered, car dependent, vulnerable to drought and wildfire, and in certain areas river flooding. Social polarization and middle class vulnerability may be on the increase. Peri-rural areas suffer from out-migration, dependency on agriculture and corporate landholdings, declining services.
Climate hazards generally include wildfires and all forms of flooding. Coastal areas are at risk from sea level rise and coastal storm hazards on critical infrastructure.
(The map here shows circles of 20, 40 & 60km radius, a rough approximation to the gravity field).
Using visual thinking for the deeper complexity of peri-urban-climate interactions, here are two images. The first is a flip-chart sketch and overview of the problem. The second is a 'causal mapping' from the Peri-cene Framework, with basic problems and pathways. For more see the Melbourne pathways:
This puts the mapping above into an analytic for with a summary table. For more see the Melbourne analysis:
(In advance of consultation this version is a comparison of our two detailed case studies).
(World Bank data profile for Victoria)
Extreme heat - Medium
Wildfire - High
Water scarcity - Low
River flood - High
Urban flood - High
Coastal flood - High
Cyclone - Low
Tsunami - High
Landslide - Medium
Earthquake - Medium
Volcano - Medium
The Peri-cene takes a practical approach to the complexity of peri-urban-climate interactions. The base-maps here build on the JRC-GHSL (Global Human Settlements Layer) system of urban mapping with 1 km2 cells http://ghsl.jrc.ec.europa.eu . In this way the peri-urban definition and mapping is not a final answer, but the start of the discussion. For more on the questions of 'where is the peri-urban?' and 'how is it changing?' download the D3-1 report.
Population density map
This shows three population density bands: 0-50, 50-125, and 125-300 persons/km2: (transparent for open land, and then green and yellow cells). These are in different proximities to the main urban centres, for the moment defined by distances (from the urban centre), of 0-20, 20-40, and 40-60km: titled 'near-urban', 'near-urban: further urban: and ex-urban / peri-rural'.
Population change map
This shows the effects of peri-urban change and urban expansion, from 1990 to 2015.
- 'Peri-urbanization': moving from rural to peri-urban
- 'Densification': moving from peri-urban to urban
- 'Urbanization': moving from rural directly to urban
Climate projections: coastal flooding
Including sea level rise, tidal, and storm surge effects, this is a 'reasonable worst case scenario' for 2080, with reduced policy and pessimistic modelling. This is based on the mapping from www.climate-central.org
Climate projections: temperature effects
(Top & middle parts include):
- temperature uplift and precipitation uplift, projected with the central ‘A1B’ scenario, for 2080-2100. Source: IPCC - AR4 - WG1 - Chapter 11-1 - https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter11-1.pdf
(Lower part includes):
- Comparison of projected temperature rise under B1, A1B, A2 emissions scenarios: Source - IPCC - AR4 - WG1 - Chapter 11-1
- Peak wet bulb temperatures 1979-2017: (note TW of 30-350 can be lethal). Source : https://research.noaa.gov/article/ArtMID/587/ArticleID/2621/Dangerous-humid-heat-extremes-occurring-decades-before-expected
- Fire (2020 summer period) & forest cover maps (>30% canopy cover): Source https://www.globalforestwatch.org
Global Forest Watch