According to Wikipedia, the planetary boundaries -concept has been around since 2009, with some renaming and one variable change (“chemical pollution” to “novel entities”. The original Nature (feature) paper that I dug up doesn’t describe the methodology, but that it hasn’t faced major criticism so far would suggest it’s pretty valid for the kind of tool that it is.
According to Wikipedia, the planetary boundaries -concept has been around since 2009, with some renaming and one variable change (“chemical pollution” to “novel entities”. The original Nature (feature) paper that I dug up doesn’t describe the methodology, but that it hasn’t faced major criticism so far would suggest it’s pretty valid for the kind of tool that it is.