Greater Melbourne
City Portrait

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The Melbourne Doughnut

Explore how well Melbourne is tracking as a place that supports people and planet to thrive.

Dimension profile

Nitrogen & Phosphorus Loading


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.

Contributors to Nitrogen & Phosphorus Loading

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.

Planetary Quotas for Greater Melbourne

Each dimension of the Ecological Ceiling is measured using per-capita Planetary Quotas for Greater Melbourne.

Nitrogen Release


Over-use of nitrogen is cutting off oxygen to critical ecosystems

What we're measuring Greater Melbourne Quotas Now

Amount of nitrogen released to waterways

Under 35.25m kg nitrogen per year 45.44m kg nitrogen per year

Phosphorus Release


Extraction and over-use of phosphorus is causing harm to ecosystems

What we're measuring Greater Melbourne Quotas Now

Amount of phosphorus released to waterways

Under 6.25m kg phosphorus per year 38.07m kg phosphorus per year

Placing Nitrogen & Phosphorus Loading in the system

Global to local connections

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.

Learn more

How was this dimension developed?

The Nitrogen & Phosphorus Loading dimension of the Greater Melbourne City Portrait has been developed in collaboration with Open Corridor with research support from the University of Melbourne. The assessment of Melbourne's environmental footprint applies a Planetary Accounting approach. A detailed description of the City Portrait methodology is outlined in the About section of the website.

Where can I access the data?

Data for Nitrogen & Phosphorus Loading, along with the other Ecological Ceiling dimensions are available in the Ecological Ceiling Dataset.

For Social Foundation dimensions, see the Social Foundations Dataset.

Where can I find more information on Nitrogen & Phosphorus Loading in a regenerative Melbourne?

The City Portrait is informed by extensive research and resources on Doughnut Economics and related frameworks, as well as sector-specific research associated with each dimension. More detailed research that has informed the Nitrogen & Phosphorus Loading dimension is available to explore via Altiorem's library.

How can I get involved?

To get involved with ongoing development of the City Portrait or learn more about Regen Melbourne, email