Years of careless consumption mean that we are quickly approaching the limits of our global system. Climate researcher Johan Rockström led a team that defined the nine critical tipping points
In 2009, Swedish climate scientist Johan Rockström and 28 other scientists asked the question: How much can Earth take before its system dynamics change so much that life on earth itself becomes threatened?
Their work resulted in a framework for sustainable human activity on Earth: The "Planetary Boundaries" theory. It outlined nine constraints that are fundamental to the stability and resilience of planet Earth. Any transgression will result in irreversible changes. Where do we stand today, 14 years later?
Freshwater use
Fresh water plays a critical role in biodiversity, food, health, and ecology.
Humans have already partially exceeded the limits of freshwater use.
Stratospheric Ozone Depletion
The ozone layer protects living creatures on Earth from the sun's UV radiation. Man-made emissions such as chlorofluorocarbons (CFCs) can destroy this layer.
Measures taken against the ozone hole since the 1990s have ensured that humans are moving within safe limits here.
Atmospheric Aerosol Loading
Aerosols, released by heaters or combustion engines, influence cloud formation (example: monsoon in Asia) and can trigger acid rain.
Since aerosol chemistry is very complex, it has not yet been possible to define a planetary boundary in this area.
Ocean Acidification
Oceans absorb about 25% of man-made CO₂ emissions. However, CO₂, acidifies the oceans, which in turn threatens biodiversity, especially for coral reefs.
The oceans are currently acidifying about 100 times faster than at any given time in 20 million years. Nevertheless, humans are still just within the green zone here.
Biogeochemical Flows
When phosphorus or nitrogen (e.g. as fertilizer) flow into rivers and lakes, the concentration of nutrients increases. The consequences are strong algal growth, oxygen deficiency, and the displacement of endemic species.
At present, humans are acting far beyond this planetary boundary.
Novel Entities
Initially referred to as "chemical pollution", released radioactive substances, heavy metals and man-made organic substances (for example plastic) can damage our health and that of entire ecosystems.
In 2022, 14 scientists concluded that humans have crossed this planetary boundary.
Land-System Change
Around the globe, forests and other ecosystems are destroyed for human use: for food and heating and cooking, and construction.
According to Rockström and colleagues, no more than 15% of the ice-free surface of the planet should be converted to cropland. Humans are not currently complying with this limit.
Biosphere Integrity
If major changes in biodiversity occur (example: mass extinction of insects), entire ecosystems may be under threat.
We are currently experiencing the sixth major mass extinction in the history of the planet - and the first caused by humans. This planetary boundary has been crossed.
Climate Change
Leaving global warming unchecked will ultimately make the earth uninhabitable for humans. The decisive factor for global warming is the CO2 concentration in the atmosphere.
Humans are on track to grossly overshoot the required Co2 limits to keep the planet below 1.5 degrees of warming.
The "Planetary Boundaries" theory has become a standard work in international climate research and Johan Rockström is recognised as one of the leading scientists and globally sought-after experts in this field.
Humankind has already crossed six of the nine boundaries. What future awaits us if we let the earth slide into climate chaos? Do we have what it takes to turn back the clock and stabilise this system before it's too late? Join Professor Johan Rockström, director of the Potsdam Institute for Climate Impact Research, as he discusses the hard decisions that need to be made with experts from science, politics and business at the GREENTECH FESTIVAL.