Modern humans, (Homo sapiens), evolved some 300,000 years ago. But modern human societies as we know them—think agriculture, animal domestication, and industrialization—developed only in the last 10,000 years or so. This was largely thanks to a stable climate that emerged around 12,000 years ago.
The stability of the planet that allowed human civilization to flourish is largely thanks to nine key processes scientists have identified. They keep the Earth’s atmosphere, oceans, land, and ecosystems in balance, allowing human societies to thrive. However, our activities over the last 200 years have rapidly destabilized these processes, according to Claire Asher for Mongabay.
The nine processes, also called the nine planetary boundaries, defined by Sweden’s Stockholm Resilience Centre, are
- Climate change
- Change in biosphere integrity, or loss of biodiversity and ecosystems
- Stratospheric ozone depletion
- Ocean acidification
- Biogeochemical flows, such as changes in phosphate and nitrogen cycles brought about by agriculture
- Land use change,
- Freshwater change
- Atmospheric aerosol loading and
- Novel entities, or harmful new substances and chemicals released by human activities
For each of these nine processes, researchers have estimated the extent to which human activities can damage them before making human civilization as we know it less possible.
In 2015, the team found that human activities were pushing at the limits of four of the nine processes. These include climate change, biodiversity loss, changes in land use and biogeochemical flows. In 2023, scientists reported that we had crossed two more planetary boundaries: changes in freshwater use and the release of novel substances. Moreover, we are edging towards the limits of atmospheric aerosol loading and ocean acidification, according to the Mongabay update.
The only process that appears to be safe for now is stratospheric ozone depletion. The shrinking of the ozone hole is, in fact, seen as a success story. It was possible only because the world’s governments recognized the urgency of the problem and worked together to resolve it.
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