There’s a new scientific paper out in the journal Nature called “Approaching a state shift in Earth’s biosphere.” In a sane world, it would be front page news. This is from the abstract:

Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence. [my emphasis]

As examples of past global state shifts, the authors cite the Cambrian explosion (“a conversion of the global ecosystem from one based almost solely on microbes to one based on complex, multicellular life,” which took a comparatively brief 30 million years), the Big Five mass extinctions, and the last glacial-interglacial transition, which started about 14 thousand years ago.

The difference today is that human beings are generating “forcings” (influences on biophysical systems) of unprecedented power at an unprecedented rate. These forcings include “human population growth with attendant resource consumption, habitat transformation and fragmentation, energy production and consumption, and climate change.” The authors emphasize that all these forcings “far exceed, in both rate and magnitude, the forcings evident at the most recent global-scale state shift, the last glacial-interglacial transition.”

This write-up from Wired adds some context:

Human activity now dominates 43 percent of Earth’s land surface and affects twice that area. One-third of all available fresh water is diverted to human use. A full 20 percent of Earth’s net terrestrial primary production, the sheer volume of life produced on land every year, is harvested for human purposes. Extinction rates compare to those recorded during the demise of dinosaurs and average temperatures will likely be higher in 2070 than at any point in human evolution.

Humanity’s footprint now covers Earth. We are shaping the biosphere in our image.