A planetary boundary process is an environmental process that is part of the Earth's regulatory system, helping it to remain in our current desired state of the Holocene. There are nine planetary boundary processes, and if humanity can manage these within safe boundaries, we have a high likelihood of enabling a prosperous future. There is extensive evidence of planetary scale tipping points to be found in the climate system, ocean acidification, and the stratospheric ozone layer. Six processes play a role in whether large-scale processes could cross a tipping point, including biosphere processes like interference of flows of nitrogen and phosphorus, global fresh water use, biodiversity, land use and anthropogenically-caused processes (aerosol loading and chemical pollution). There are tipping points among these that operate at less than the planetary scale as well.