Dr Anjani Ganase considers the planetary boundaries that allow human expansion, civilisation and existence.
Last year, I reported on the planetary boundaries that should not be exceeded for human civilisation to continue in the way we’ve known. The last report was produced in 2015, and this year the results have been updated with new information collected over the last eight years. The latest study highlights nine planetary boundaries, six of which are currently being transgressed. All nine components must occur within safe operating zones for humanity.
What you need to know:
All planetary boundaries refer to conditions that have significance for the environment that supports human well-being.
Three main zones have been defined: zone of safe operation, zone of increasing risk, and zone of high risk. The latter two zones indicate conditions that exceed the planetary boundary. The planetary boundary has a baseline of the Holocene epoch (before the industrial revolution) which represents a window of about 11,000 years of highly stable environmental and biological conditions when human civilisation occurred without significantly altering the planet.
[caption id="attachment_1038612" align="alignnone" width="1024"] Current status of control variables for all nine planetary boundaries. Six of the nine boundaries are transgressed. In addition, ocean acidification is approaching its planetary boundary. The green zone is the safe operating space (below the boundary). Yellow to red represents the zone of increasing risk. Purple indicates the high-risk zone where interglacial Earth system conditions are transgressed with high confidence. Sourced from Richardson et al (2023) Scientific Advances -[/caption]
During this period, the global temperature never varied more than 0.5C. In contrast, over the last 100 years since the advent of the industrial revolution, human activities have been rapidly altering planetary conditions, with climate change being one that rapidly deviates from Holocene conditions, such as 1.3C temperature rise since pre-industrial conditions just over 100 years ago.
High risk: where we are failing
Here are the planetary components that occur in the zone of high risk (boundaries have been transgressed with significant departure from baseline values:
Biosphere integrity
The biosphere (the living natural world) co-evolved with the geo-physical world. Scientists measure biosphere integrity by genetic diversity and function. Higher integrity refers to the biosphere’s ability to adapt genetic diversity and maintain ecological function in response to a changing physical and chemical environment.
Such adaptations are critical when considering food production, disease control and plant and microbes that form critical life-supporting functions.
We measured biosphere integrity by the rate of extinctions and loss of genetic diversity. Currently, the extinction rate is 100-1,000 times the baseline.
This is largely driven by human activities, such as land clearing, exploitation and habitat tran
