DR AXEL KRAVATZKY
This Earth Day, we can ask ourselves some hard questions about personal consumption, needs and wants.
Copy the Earth Day Checklist, discuss it, write it down somewhere and remember it.
We are currently living in the decade that will define the future for humanity and life on Earth, says Kimberly Nicholas, a sustainability scientist at Lund University in Sweden. Her ultra-concise summary of what we know about climate science is this: “It’s warming. It’s us. We’re sure. It’s bad. We can fix it.”
Thirteen years ago, Johann Rockstroem, founder of the Stockholm Resilience Centre, led a team of scientists who published a feature in the prestigious science journal Nature, in which they sought to identify and quantify the most essential planetary boundaries that must not be transgressed in order not to cause unacceptable environmental change.
Modern humans, Homo sapiens, can be traced back to about 200-300,000 years ago. When we look at a graph charting temperature variations over the past 100,000 years, we notice that temperatures were volatile for 90,000 years, with average temperature changes as high as +/- 10 degrees in a single decade, and then about 10,000 years ago the earth entered a remarkably stable temperature period. Over the past 10,000 years average temperatures varied by only +/- 1 degree.
This geological epoch was named the Holocene. Even though humans existed long before the Holocene, it was during this period of environmental stability that humans began to flourish and civilisation emerged.
Since the onset of the industrial revolution in the early 1800, humans have created so much impact on the planet that it has been suggested that a new geological epoch has started: the Anthropocene – the age of humans.
Environmental change took place during the Holocene, but the Earth’s regulatory capacity maintained conditions that enabled human development. Research by Rockstroem and his colleagues showed temperatures, freshwater availability, and biochemical flows all stayed within a relatively narrow range.
“Once humans started to rely on fossil fuels and industrialised forms of agriculture, human activities have reached a level that could damage the systems that keep Earth in the desirable Holocene state. The result could be irreversible and, in some cases, abrupt environmental change, leading to a state less conducive to human development,” say Rockstroem and colleagues.
“Over the past 50 years we have pushed ourselves outside of the state that we have been in for 10,000 years,” says Rockstroem in the recently released Netflix documentary Breaking Boundaries: the Science of our Planet.
In order to navigate this dangerous territory, scientists have proposed a framework based on planetary boundaries. These boundaries are meant to define the safe operating space for humanity with respect to the Earth’s systems. The boundaries are associated with the planet’s biophysical subsystems and processes.
In 2009, when the planetary boundary framework was first presented, scientists
