Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Wild mammal biomass has declined by 85% since the rise of humans

ourworldindata.org

Post reply on HN
Print view View original

121–130 of 447 posts

Re: Wild mammal biomass has declined by 85% since the rise of humans

#121

Post by club_tropical »

myshpa wrote: post #106
club_tropical wrote: post #44

Earlier quoted context omitted.

Also, “biomass” is a strange term. Is that literally an estimate of mass? Or count of individuals? Many other context lacking as well. This is clearly written for the 96% statistic shock, not to inform anyone.

RTFA. "To understand how the richness of the mammal kingdom has changed we need a metric that captures a range of different animals and is comparable over time. We could look at their abundance – the number of individuals we have – but this is not ideal. We would be counting every species equally, from a mouse to an elephant and this metric would therefore an ecosystem taken over by the smallest mammals look much ric…

PERCENTAGE biomass in NO WAY reflects “the richness of the mammal kingdom”. It is a synthetic metric that scientists can futz around with enough to produce some shocking metric and get funding/press.

ABSOLUTE “biomass” is meaningful, simply because mammals have relatively tight weight ranges and you can estimate the individual counts from the biomass- but let’s be real: it is most likely that they start with estimates of number of individuals and multiply that by the average weight to get biomass. So- ditch the biomass and show absolute numbers of individuals over time. That is meaningful.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#122

Post by glitcher »

myshpa wrote: post #59

The sad thing is that 100 years ago humans and livestock accounted for around 5% of the biomass (all zoomass, not land mammals only), 95% being the wildlife. Now the numbers are reversed. We've stolen the land from the wildlife and dedicated it to a few species we consider edible (agriland is more than forests now, and 75% of it for animal agriculture). Is anybody surprised that we're living in the anthropocene, defi…

Reminds me of George Carlin, "The earth will be fine..."

Re: Wild mammal biomass has declined by 85% since the rise of humans

#124

Post by creata »

SCUSKU wrote: post #109
retrac wrote: post #25

Going off on a tangent, but the scale of production is very hard to grasp. I'm probably not the first person to observe this, but I once did some napkin math about steel production, and what I realized kind of blew me away. About 1.9 billion tonnes in 2020. Like with billions of dollars, I have no intuition for such numbers. Context is needed. Global steel production just before WW I was about 70 million tonnes. So p…

I made a website to help visualize American meat consumption in terms of animals slaughtered per second. It’s pretty insane and I think does something to help communicate just how large such industrial operations truly are. https://zach.ws/meat/

Hey, don't let me tell you how to run your website, but it took me a while to realize that I should scroll. You could add a little "scroll down ↓" indicator that fades in after a bit.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#125

Post by joebob42 »

epicureanideal wrote: post #111
patrec wrote: post #98

Earlier quoted context omitted.

So modern civilization currently requires the average human to consume roughly 3-4 times his body weight in steel per year. And given that steel production has roughly doubled in the last 20 years, this will probably still go up a fair deal.

If population levels off I would imagine the need for steel would mostly level off also? I assume the main use is in construction?

Per gp, it's consumption. Perhaps you haven't been eating enough steel to appreciate the demand.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#126

Post by nemo44x »

SCUSKU wrote: post #109
retrac wrote: post #25

Going off on a tangent, but the scale of production is very hard to grasp. I'm probably not the first person to observe this, but I once did some napkin math about steel production, and what I realized kind of blew me away. About 1.9 billion tonnes in 2020. Like with billions of dollars, I have no intuition for such numbers. Context is needed. Global steel production just before WW I was about 70 million tonnes. So p…

I made a website to help visualize American meat consumption in terms of animals slaughtered per second. It’s pretty insane and I think does something to help communicate just how large such industrial operations truly are. https://zach.ws/meat/

Ha that’s great! Hopefully we continue to see these numbers as increase as a leading indicator of a wealthy and well fed society.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#127

Post by jonnycomputer »

club_tropical wrote: post #114
jonnycomputer wrote: post #101

Earlier quoted context omitted.

Biomass is probably exactly the right measure, when we are talking ecology. A lot of mice to weigh up to one cow, it is true, but then, you could feed a lot of mice on the grain with which you feed your cow.

I understand that each animal group has a different weight range and that, if you reduce animal groups to “total weight” metric, you can compare cows with mice on that metric. I do not agree that this is some kind of meaningful unit, especially in percentage terms, for anything that ecologists might be interested in, like population health, or whatever else. The fact that ecologists think in terms of biomass while pu…

All you've done is asserted it doesn't make sense. You could at least make an argument as to why.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#128

Post by club_tropical »

pvaldes wrote: post #115
club_tropical wrote: post #105

Earlier quoted context omitted.

I think it is an unclear and bizarre term. “The energy contained in one group” - what energy? Is a lean cheetah “less-energy” than an elephant? Why? Or do you literally mean energy like calories (which, IIRC means “how much heat if burned”). What a bizarre metric, nobody thinks like this, I don’t even think “ecologists” understand why they should think in terms of mass. I, too, can have a metric: number of decibels o…

> “The energy contained in one group” - what energy? The chemical energy contained in the links of the molecules > Is a lean cheetah “less-energy” than an elephant? Yes, of course. One cheetah, has less biomass than one elephant. But -the- rats, have more biomass than -the- elephants. Is the beauty of the ecology. > What a bizarre metric, nobody thinks like this, I don’t even think “ecologists” understand why they sh…

> The professionals that use it, obviously, know their job. They aren't stupid.

I will not defer to authority. I want an explanation for why the percentage of aggregate “chemical energy contained in the links of molecules” is considered a meaningful metric for anything other than “how much percentage heat would I produce if i threw them into a fire”, let alone mammal population health or diversity.

> Well, the difference is that nobody uses your metric.

Correct, because it is not meaningful, and neither is biomass.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#129

Post by thegrimmest »

davzie wrote: post #90
thegrimmest wrote: post #84

Earlier quoted context omitted.

> otherwise we'll lose them So what? What value are these species? What are they for ? I'm sure we'll be able to advance medicine in other ways. I'm much more concerned about the longevity of our civilization than the other organics we happen to have coevolved with. If we have to pave over the whole planet then so be it. Organic life is common and therefore expendable. If we all die off, new life will almost certainl…

This HAS to be trolling!

Believe it or not, I'm actually looking for a good faith refutation that doesn't rely on sentiment.

Re: Wild mammal biomass has declined by 85% since the rise of humans

#130

Post by dragonwriter »

thegrimmest wrote: post #129
davzie wrote: post #90

Earlier quoted context omitted.

This HAS to be trolling!

Believe it or not, I'm actually looking for a good faith refutation that doesn't rely on sentiment.

Value is sentiment; you cannot refute a value statement without relying on it.
Post reply on HN