The Earth’s biomass is estimated as 550 gigatons of carbon (GT C); of that what is the weight of humankind?

here is a quick calculation 67kg humans= 15 people per tonne. = 15 000 000 000 or 15 billion people per Gigatonne. There are half that many humans on the planet (a bit over 7 billion). 67 kg/human might seem light to westerners. But a quarter of the worlds population is under 14yo. And half of the population is in Asia (lighter than westerners). So the gross mass of humans is about half a Gigatonne or less.

In addition to your comment, Tom. Americans count for approximately one third of a billion people, compared to a world of over 8 billion. And whilst the (unfair) stereotype of Americans is that they are grossly overweight, that applies to less than a quarter of them.

Tom, your math doesn’t jive with the answer of .06 GT C.