Is there a reliable estimate of the number of cells on Earth?

Question

A quick Google search didn't turn up any reliable sources. An awkward Cosmoquest thread (https://forum.cosmoquest.org/showthread.php?141294-How-many-living-cells-are-there-on-Earth) gives a rough estimate of 10^25 to 10^32, but this is just a bad extrapolation of the number of cells in a human body. Also, I recently learned that we don't even know the number of cells in humans to good precision.Has anyone ever made a serious attempt to figure this out? If not, does anyone here want to make a quick calculation?

Answer 1

As you can guess, this number is hard to determine. There is so many unknown variables: the number of cells in the human body, how many people live on earth, how many flora and fauna are on earth, the number of cells that compromise these, etc. Unfortunately, as of now, the best we can do is make extrapolations until better methods arise.