ABCDEFGHIJKLMNOPQRSTUVWXYZAAABAC
1
GREATER MELBOURNE CITY PORTRAIT
ECOLOGICAL CEILING DATASET
2
DimensionQuotaQuota description (short)IndicatorGreater Melbourne QuotaCurrent impact valueUnitsData sourceData inputsDimension descriptionQuota description (full)Contributors to dimensionGlobal to local connections
3
Climate ChangeCarbon EmissionsCarbon dioxide emissions are trapping heat in the atmosphereNet emissions of carbon dioxide-6.82E+063.29E+07tonnes CO2 equivalent per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Australian National Greenhouse Accounts, DCCEEW; Australian Energy Regulator (AER); Australian Energy Market Operator (AEMO); Electricity distribution networks (DNSPs); International Energy Agency (IEA); EDGAR (Joint Research Centre & Netherlands Environmental Assessment Agency)When greenhouse gases such as carbon dioxide, methane and nitrous oxide are released into the air, they enter the atmosphere and amplify Earth’s natural greenhouse effect, trapping more heat within the atmosphere. This results in global heating. Its effects include rising temperatures, more frequent droughts, floods and storms, and sea level rise. How we live, work and play in Melbourne (including the goods and services we produce and consume) has an impact on the global climate.The Intergovernmental Panel for Climate Change published a report outlining several pathways for limiting warming to 1.5C (a limit that aligns with the intent of the Planetary Boundaries limits for climate change). All of these pathways show that by between now and 2100, all non-biogenic greenhouse gas emissions must reach zero and that carbon dioxide must be drawn out of the atmosphere. In contrast the pathways show continued biogenic emissions out to 2100 and beyond because these emissions are necessary to enable sufficient agricultural production to feed the global population.

As such, non-biogenic emissions and all emissions of carbon dioxide can be combined into a single indicator measured in emissions of carbon dioxide equivalent with the long-term Quota set at the maximum carbon uptake per year this century of 12GtCO2e with maximum cumulative carbon dioxide emissions of 320GtCO2 this century.		Climate change is influenced by:

- A build-up of greenhouse gases in the atmosphere
- Changes to the reflectivity of the Earth’s surface (such as greater areas of dark blue ocean, which absorbs heat, and reduced areas of snow and ice coverage, which reflect heat)
- Changes in aerosol levels in the atmosphere (small particles of dust and chemicals) and associated changes to cloud cover

Contributors to climate change include:

- Burning fossil fuels for electricity generation, fuel combustion and transport
- Emission of greenhouse gases such as methane from agriculture and waste
- Production of chemicals and cement		Impacts of human-induced climate change are already evident not only internationally, but also here in Australia. For example, we continue to break records for average seasonal and annual temperatures, and are experiencing extreme weather events with greater frequency and severity.

Reducing Greater Melbourne's contribution to climate change and its effects globally and locally can come from:

- Accelerating our transition to renewable energy sources
- Electrifying our appliances to reduce energy demands
- Shifting to less energy-intensive activities, such as increasing active transport over car-based travel
- Storing more carbon through enhanced greening
- Divesting from emission-intensive investments
4
Climate ChangeNon-CO2 GHGsPotent gases other than carbon dioxide are contributing to the greenhouse effect and global warmingNet emissions of non-carbon dioxide greenhouse gases (such as methane, nitrous oxide and fluorinated gases)2.84E+062.80E+07tonnes CO2 equivalent per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Department of Climate Change, Energy, the Environment and Water (DCCEEW); EDGAR (Joint Research Centre & Netherlands Environmental Assessment Agency)When greenhouse gases such as carbon dioxide, methane and nitrous oxide are released into the air, they enter the atmosphere and amplify Earth’s natural greenhouse effect, trapping more heat within the atmosphere. This results in global heating. Its effects include rising temperatures, more frequent droughts, floods and storms, and sea level rise. How we live, work and play in Melbourne (including the goods and services we produce and consume) has an impact on the global climate.Biogenic-GHGs encompasses the methane and nitrous oxide emissions derived from biogenic sources (i.e., agriculture and waste water) and is measured in the unit carbon dioxide equivalents. In the IPCCs fifth assessment report, the most ambitious future emission scenario (RCP2.6) showed end-of-century emissions for methane dropping to <143Mt/year and nitrous oxide to <5.3 MT N/year, a combined global warming potential of <5GtCO2e.

The basis of this limit was the lowest feasible emissions that would still enable sufficient agricultural production to meet the nutritional needs of the global population.		Same as aboveSame as above
5
Land ConversionLand UseLand converted for agriculture and urbanisation is reducing habitat and natural carbon captureArea of land converted to anthropised uses (e.g., urbanisation and farming)1.05E+048.68E+04km2 per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Australian Bureau of Agricultural and Resource Economics (ABARES); Food and Agriculture Organization of the United Nations (FAOSTAT)Converting land for human use – such as turning forests and wetlands into cities, farmland and highways – depletes Earth’s carbon sinks, destroys rich wildlife habitats, and undermines the land’s role in continually cycling water, nitrogen and phosphorus.The level of reforestation needed to return to all of these Planetary Boundaries is an average of 11 million hectares per year (i.e., Deforestation ≤ -11MHa/year) in order to return the total global forest area to 4.9 billion hectares by the end of this century. Given the challenges in rigorously accounting for change in deforestation, the quota is instead set to the area of anthropised land, as proposed by Dao et al. (2015, 2018), with a global limit of 19,400,000 km2.Land Conversion (or land-use change) occurs when human activities transform a natural landscape from one land type to another. Forests are one of the most important land-based habitat, with approximately 80% of the world’s terrestrial species found in tropical forests. They also provide significant natural benefits to humans, including their role in the carbon cycle.

Contributors to harmful Land Conversion include changing natural landscapes into:

- Cultivated cropland
- Urbanised / developed areas
- Mines and other sites of resource extraction
Land Conversion on a global scale is the cumulative effect of both large and small changes at a local level. The large geographic footprint in Greater Melbourne has permanently changed the landscape, but opportunities exist to reduce the impacts that the city has had on its ecosystems.

Land Conversion in Greater Melbourne can be slowed or reversed through:

- Prioritising infill development over greenfield development to support growth of the city
- Re-wilding landscapes in and around the city
- Retaining trees when land-use changes occur where they exist

Impacts from land use and land-use change can be reduced globally by:

- Switching to less land and energy intensive dietary patterns (e.g., plant-based)
- Growing and consuming locally grown foods
- Avoiding purchasing products linked to deforrestation
- Divesting from land-intensive primary industries (e.g., palm oil)
6
Freshwater WithdrawalsWater ConsumptionExcessive water consumption is impacting waterway health and stability of water systemsVolume of blue water consumption4.83E+091.19E+09m3 per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Melbourne Water; Pfister and Bayer 2011; WaterGAP data (Flörke et al., 2013)Water is essential for life and is widely used by agriculture, industry and households. Excessive withdrawals of water, however, can impair or even dry up lakes, rivers and aquifers, damaging ecosystems and altering the hydrological cycle and climate.The original Planetary Boundary for blue water is consumptive Use < 4000km3. Recent research defines a limit for green water based on root-zone soil moisture <10% of the land area in which root- zone soil moisture is wetter or drier than the local variability bounds. The quota for water considers blue, green and grey water. While there is no consensus as to a global water budget for net blue, green, and grey water, given that even at current consumption rates many of our global water bodies are under stress, it follows that the upper limit should not exceed current consumption rates. As such, the Planetary Quota was set at net water (blue, green, and grey water) footprint ≤8500 km3.Human interventions in blue and green water functions could generate non-linear and irrevocable change, and collapse, in ecosystems and hydrological systems.

Contributors to Freshwater Withdrawals include:

- Excessive freshwater consumption by households, industry and government that depletes water supplies
- Redirection or artificial control of waterways that alters their natural, life-supporting functionality		Australia is the driest inhabited continent and feels the effects of drought acutely. The control and management of water supplies are contentious issues nationally, regionally and at local levels and associated decision-making visibly impacts ecosystem health, local economies and community health and wellbeing.

Care for Greater Melbourne's water systems can be enhanced through actions such as:

- Increasing use of recycled water to reduce pressure on drinking water supplies
- Capturing stormwater through design interventions to naturally water urban landscapes
- Building soil moisture and health to better retain water and reduce the need for watering
- Planting landscapes that are suitable to Greater Melbourne's anticipated future climate
7
Nitrogen & Phosphorus LoadingNitrogen ReleaseOver-use of nitrogen is cutting off oxygen to critical ecosystemsAmount of nitrogen released to waterways3.53E+074.54E+07kg nitrogen per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Australian Bureau of Agricultural and Resource Economics (ABARES); Food and Agriculture Organization of the United Nations (FAOSTAT)Reactive nitrogen and phosphorus are widely used in agricultural fertilisers, but only a small proportion of what is applied is actually taken up by crops. Most of the excess runs off into rivers, lakes and oceans, where it causes algae blooms that turn the water green, brown or even red. These blooms can be toxic, and they kill off aquatic life by starving the water of oxygen.The Planetary Boundary for nitrogen is a maximum of 62 Tg N/year of intentionally fixated nitrogen. While this indicator is scalable, it is not easily comparable to human activity, and as discussed for water treatment, excludes opportunities for positive activities such as the denitrification of waste-water. Synthetic nitrogen applied to land eventually leads to waterways whether this is lost to the environment during the production of food, or after the consumption of food via sewage streams, unless it is actively removed. As such, the Quota for Nitrogen is net nitrogen used ≤ 62 Tg N.Contaminated runoff from the excessive use of nitrogen and phosphorus is problematic in freshwater systems and also presents significant risk from the flow of these systems into the ocean. Such flows of phosphorus have the potential to lead to large-scale ocean anoxic events (insufficient dissolved oxygen in the ocean), which have previously been associated with mass-extintion events. Similarly, excessive flows of nitrogen into the ocean cause eutrophication of aquatic ecosystems, wherein excessive algal blooms create dead zones and fish kills.

A few agricultural regions globally with very high fertiliser use have historically contributed disproportionately to Nitrogen and Phosphorus Loading. However, excess fertiliser use in any location contributes to global and local risks.		Our waterways are vulnerable to the effects of Nitrogen and Phosphorus Loading, which makes this both a global and a local issue to address.

Minimising the effects of Nitrogen and Phosphorus Loading in Greater Melbourne can be achieved through regenerative farming and related methods that focus on alternatives to synthetic fertilisers to build soil health. This includes shifting agricultural activities occurring in the metropolitan area, as well as incresing consumption of products grown regeneratively outside of the city.
8
Nitrogen & Phosphorus LoadingPhosphorus ReleaseExtraction and over-use of phosphorus is causing harm to ecosystemsAmount of phosphorus released to waterways6.25E+063.81E+07kg phosphorus per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Australian Bureau of Agricultural and Resource Economics (ABARES); Food and Agriculture Organization of the United Nations (FAOSTAT)Reactive nitrogen and phosphorus are widely used in agricultural fertilisers, but only a small proportion of what is applied is actually taken up by crops. Most of the excess runs off into rivers, lakes and oceans, where it causes algae blooms that turn the water green, brown or even red. These blooms can be toxic, and they kill off aquatic life by starving the water of oxygen.The primary Planetary Boundary limit for phosphorus is a flow of no more than 11 TgP/year from freshwater systems to the ocean. This is already a pressure indicator. However, in this instance, the metric is describing the movement of a substance between two environments rather than describing a flow from human activity. This means that it is difficult to compare directly to human activity. However, like for nitrogen, the maximum flow of phosphorus from freshwater systems to the ocean equals the amount of phosphorus released to the environment by human activity. As such, the Quota for phosphorus is net phosphorus released to the environment ≤ 11 Tg/year.Same as aboveSame as above
9
Air PollutionAerosol EmissionsSmall particles in the air are causing poor air quality and impacting health outcomesImpact on air quality of the emission of aerosols and precursor gases5.69E-051.35E-05AOD equivalent per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Environment Protection Authority Victoria; World Health Organization (WHO); EDGAR (Joint Research Centre & Netherlands Environmental Assessment Agency)Micro-particles, or aerosols, emitted into the air – such as smoke, dust and pollutant gases – can damage living organisms. Furthermore, they interact with water vapour in the air and so affect cloud formation. When emitted in large volumes, these aerosols can significantly alter regional rainfall patterns, including shifting the timing and location of monsoon rains in tropical regions.While no amount of air pollution is considered “safe” a review of the Planetary Boundary for AOD of 0.1 shows that this would respect the World Health Organization's recommendations for minimum air quality. The range of AODe that could be used to respect the PB for radiative warming – considering the potential variability of other Quotas, is between 0.04 and 0.13.Aerosols are from direct or primary emissions and as a result of indirect or secondary emissions from other sources. Aerosols are the basis for air pollution which can be harmful to human health. They impact climate change with both warming and cooling impacts.

Primary Aerosol Emissions include:

- Sea salt
- Dust
- Black carbon, from fire or fossil fuel combustion (such as diesel engines)
- Ammonia, from fertiliser use in agriculture
- Nitrogen oxides, primarily from motor vehicles but also from volcanic activity and fires
- Organic carbon, from combustion
- Sulphur dioxide, primarily from burning coal and oil, but also from volcanic activity		Aerosol Emissions contribute to climate change and associated weather patterns globally while harming health closer to the places where they occur. In Greater Melbourne, poor air quality became especially apparent during the Black Summer bushfires.

Improving air quality in Greater Melbourne can happen through:

- Accelerating our transition to renewable energy sources, particularly for transport and industry
- Planting trees to capture aerosols
- Avoiding harmful activities that release aerosols
10
Biodiversity LossBiodiversity LossHuman activities that reduce biodiversity are putting the health and resilience of ecosystems at riskPotentially Disappeared Fraction (PDF) of species5.69E-072.84E-06PDF per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Atlas of Living Australia; Life Cycle Impact Assessment indicators, UNEP Life Cycle InitiativeA decline in the number and variety of living species damages the integrity of ecosystems and accelerates species extinction. In doing so, it increases the risk of abrupt and irreversible changes to ecosystems, reducing their resilience and undermining their capacity to provide food, fuel and fibre, and to sustain life.Land-use change is considered by many to be the greatest threat to biodiversity, and several land-use proxy indicators have been established for biodiversity impacts. The indicator, Potentially Disappeared Fraction (PDF) of species, aligns well with the Planetary Boundary metric for biosphere integrity (extinction rate) as both are expressed in terms of the percentage of extinct (or disappeared) species. The PB sets out the maximum global extinction rate as 10 species per million species per year - i.e. ≤1 × 10−4/year. As such, the PQ is set at PDF ≤1 × 10−4/year.Human activity has had more severe impacts on biodiversity in recent years than any other period in history, and this is continuing to increase.

Biodiversity loss is caused by:

- Urban development and land-use changes that replace natural environments and disrupts corridors where wildlife live and move
- Introducing non-native species that overwhelm native species create ecosystem imbalance
- Excessive extraction of native species that puts pressure on their ability to maintain healthy populations
- Changes to climate and local conditions (such as through pollution) that make habitats uninhabitable
Biodiversity loss disrupts ecological conditions on both global and local levels. Steps taken across Greater Melbourne can reduce negative biodiversity impacts and contribute to regeneration at a city scale, simultaneously reducing risks of irreparable global harm.

Biodiversity in Greater Melbourne can be enhanced through actions such as:

- Changing development patterns to preserve natural habitats and wildlife corridors
- Reducing pollution in natural environments, including waterways
- Enhancing soil quality
- Urban rewilding programs that reintroduce native species and re-establish biodiversity corridors
- Divesting from assets linked to biodiversity threats
11
Chemical PollutionImperishable WasteHuman-created waste that does not break down is harming ecosystems and human healthNet amount of non-biodegradable or toxic waste permanently released to the environment9.44E+051.28E+06tonnes per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Department of Climate Change, Energy, the Environment and Water (DCCEEW); Sustainability VictoriaWhen toxic compounds, such as synthetic organic pollutants and heavy metals, are released into the biosphere, they can persist for a very long time, with effects that may be irreversible. When they accumulate in the tissue of living creatures, including birds and mammals, they reduce fertility and cause genetic damage, endangering ecosystems on land and in the oceans.Recent studies have proposed focusing on the proportion of chemicals released into the environment that have been thoroughly tested for safety and are monitored (Persson et al., 2022). Imperishable waste is used as a proxy indicator to capture at least some of the intent of this boundary. There is strong evidence that we have already gone beyond the global limit for imperishable waste assimilation. To incorporate opportunities such as landfill mining, the metric is net imperishable waste ≤ 0kg.Chemical Pollution is a result of toxins released by novel entities, which are any new or altered substances or life forms that have the potential to create unwanted environmental effects. These impact ecosystems and human health through waste generation and direct consumption.

Sources of Chemical Pollution include:

- Chemicals, including 'forever chemicals' (PFAS) found in many everyday products like cosmetics, food packaging, cookware and clothing
- Engineered materials or organisms
- Naturally occurring elements, such as heavy metals, when these are concentrated as a result of human use, such as lead in paint		The effects of chemicals through both consumption of substances and the accumulation of imperishable waste can feel abstract, but have real effects on ecosystems and people in Greater Melbourne.

Significant opportunities to reduce the impacts of Chemical Pollution in Greater Melbourne include activities such as:

- Increasing consumption of products that do not contain harmful chemicals (and phasing out products that do contain these substances)
- Reducing the volume of waste that ends up in landfills
- Havesting and treating stormwater
12
Ozone Layer DepletionOzone-depleting SubstancesChemical substances that weaken the ozone layer are increasing harmful UV exposureMontreal gas emissions9.58E+001.37E+00tonnes ODP per yearOpen Corridor (2023) 'Environmental Footprints of Greater Melbourne, 2021'. doi:10.5281/zenodo.10099457Department of Climate Change, Energy, the Environment and Water (DCCEEW); Ozone Secretariat, UN Environment Programme (UNEP)Earth’s stratospheric ozone layer filters out ultraviolet (UV) radiation from the sun, protecting life on earth. Some human-made chemical substances, such as chlorofluorocarbons (CFCs) will, if released, enter the stratosphere and deplete the ozone layer, exposing Earth and her inhabitants to the sun’s harmful UV rays.ODP is a measure of how much ozone depletion occurs per kilogram of emission relative to the impacts of a kilograme of CFC-11 (the benchmark gas with an OPD of 1). This metric is used to capture all ODSs into a single metric “Montreal Gases” measured in ODPkg.The appearance of a “hole” in the ozone layer is an example of an Earth-system threshold being crossed. Any thinning of the ozone layer has negative impacts on marine organisms and poses risks to human health.

Most ozone-depleting substances have been phased out through international agreement. Some substances are still in use because effective alternatives have not been identified; these include:

- Methyl bromide, used as a fumigant in quarantine settings
- Halon, used to suppress fires in contained environments such as airplanes and submarines		The ozone layer is an example of the power of global collaboration. After decades of releasing vast amounts of ozone-depleting substances into the stratosphere, current trends suggest that the Montreal Protocol - a global agreement to phase out the use of ozone depleting substances - has put us on track to repair the ozone layer, returning to pre-1980 levels by 2065.

Australia has been especially exposed to the thinning of the ozone layer due to our latitude, and therefore has a significant amount to gain from repair as a result of phasing out ozone-depleting substances. This offers a strong example of localised impacts from global action, and a critical motivator for Australia to adhere to global protocols for minimising use of substances that are harmful to the ozone layer.
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100