Cape Grim baseline air pollution station in Tasmania has measured carbon dioxide levels providing a true background sample of Earth’s atmosphere free from local industrial contaminants. According to records cited from the Bureau of Meteorology and CSIRO, atmospheric carbon dioxide stood at 330 ppm when measurements began in 1976. This long-term monitoring effort anchors global understanding of humanity’s impact on climate change, tracking shifts alongside historical metabolic revolutions that shaped the biosphere.
Six Revolutions That Remade the Earth Biosphere
According to author Ian Angus in his book Metabolic Rifts: Capitalism’s Assault on the Earth System, the history of life on Earth is the history of living things obtaining, processing, and exchanging matter and energy. Angus identifies six major developments that transformed a formerly dead planet. For the first billion years, Earth had no biosphere until cooling allowed the emergence of living single-celled organisms in a carbon dioxide-rich, oxygen-free environment. Approximately one billion years later, early photosynthesis developed as cyanobacteria evolved chlorophyll and the enzyme RubisCO to fix carbon dioxide and split water.
This biological activity triggered the Great Oxygenation Event, allowing an ozone layer to form and block lethal ultraviolet light. About two billion years ago, symbiotic life produced larger cells with nuclei, eventually leading to the Cambrian Explosion between 530 and 520 million years ago, when complex multicellular animals emerged. According to the historical record, these animals became powerful geobiological agents that altered nutrient cycling and environmental feedbacks. About 475 million years ago, algae and fungi formed the ancestors of lichens, conquering the land and eventually lifting atmospheric oxygen levels to 20 percent or higher, paving the way for terrestrial plants and modern animal forms.
“Living matter and the rest of the planet have co-evolved, changing and being changed by each other. Every major change eliminated the conditions that made previous changes possible,” Angus observes regarding these irreversible planetary tipping points.
4.5 Billion Years of Earth's History in JUST 1 Hour | Full Documentary
