No non-trivial total biomass change occurs on scales shorter than thousands of years
"The biomass is the mass of living biological organisms in a given area or ecosystem at a given time."
Of course fish and insects are part of the biomass.
This paper tries to measure the thing you claimed as 75% over the last hundred or so years as actually being around 45% over the last 5,000 years. http://vaclavsmil.com/wp-content/uploads/PDR37-4.Smil_.pgs61... I found this on the greenpeace website, so if anything this is probably a gross overestimate.
Let's assume good faith on both sides, otherwise this discussion will go nowhere. Agreed?
> They’re not the total biomass
No, they're not. I never claimed that. My claim was that
>> Of course fish and insects are part of the biomass.
Anyway. That out of the way, let's have a look at
> Just because a couple species types have declined by X%,
It's not a couple of species. It's whole ecosystems that are being emptied. The Zoological Society of London report [0] monitors 4392 vertebrate species. There's a consistent and dramatic reduction.
> This paper tries to measure the thing you claimed
Thanks for the research and for taking it serious enough to do some data hunting. I'll happily dig into the report. Since it's from 2011, I wonder if there's an updated version that includes more recent data.
I honestly don't have a better source that aggregates the loss globally over all species. I would be interested in more exact numbers. (Ask HN?!)
>>>> but at least might not be off by orders of magnitude.
I think we have established that the 75% is not "off by orders of magnitude". Could it be 60% reduction? Or 50%? Sure. Absent more data this could be possible, certainly. Given that it's only been a few decades, I don't think that matter too much - it's devastating in any case.
But I think we can agree that it's definitively above 7.5% or 0.75%. I honestly think that 75% is not too far off.
[0] https://www.zsl.org/sites/default/files/LPR%202020%20Full%20...
