| Likelihood | Expected frequency of a given threat |
|---|---|
| Almost certain | Expected to occur more or less continuously throughout a year |
| Likely | Not expected to be continuous but expected to occur one or more times in a year |
| Possible | Not expected to occur annually but expected to occur within a 10-year period |
| Unlikely | Not expected to occur in a 10-year period but expected to occur in a 100-year period |
| Rare | Not expected to occur within the next 100 years |
Based on current management
| Consequence | Ecosystem (natural heritage) | Heritage (Indigenous, historic and other) | |
|---|---|---|---|
Broad scale | Local scale | ||
| Catastrophic | Impact is clearly affecting, or would clearly affect, the nature of the ecosystem over a wide area. Recovery periods greater than 20 years likely. | Impact is destroying, or has the potential to destroy, a class or collection of heritage places on a large scale; or is clearly affecting, or would clearly affect, a range of heritage values over a wide area. | |
| Major | Impact is, or would be, significant at a wider scale. Recovery periods of 10 to 20 years likely. | Impact is, or would be, extremely serious and possibly irreversible to a sensitive population or community. Condition of an affected part of the ecosystem possibly irretrievably compromised. | Impact is adversely affecting, or would adversely affect, the heritage values of a number of places; destroy individual heritage places of great significance; or significantly affect the heritage values over a wide area. |
| Moderate | Impact is, or would be, present at a wider scale, affecting some components of the ecosystem. Recovery periods of five to 10 years likely. | Impact is, or would be, serious and possibly irreversible over a small area. Recovery periods of 10 to 20 years likely. | Impact is adversely affecting, or would affect, individual heritage places or values of significance; or affect to some extent the heritage values at a wider scale. |
| Minor | Impact is, or would be, not discernible at a wider scale. Impact would not impair the overall condition of the ecosystem, or a sensitive population or community, over a wider level. | Impact is, or would be, significant to a sensitive population or community at a local level. Recovery periods of five to 10 years likely. | Impact is adversely affecting, or would affect, heritage places or values of local significance, but not at a wider scale. Impact would not impair the overall condition of the heritage values. |
| Insignificant | No impact; or if impact is, or would be, present then only to the extent that it has no discernible effect on the overall condition of the ecosystem. | No impact; or if impact is, or would be, present then only to the extent that it has no discernible effect on the overall condition of the ecosystem. | No impact; or if impact is, or would be, present then only to the extent that it has no discernible effect on the heritage values; or positive impact. |
Likelihood and consequence is combined to determine risk level, consistent with the principles and guidelines of the Australian Standard for risk management (AS/NZS ISO 31000:2018). Risk level is considered to be residual — the risk that remains once existing management measures have been taken into consideration.
