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

ourworldindata.org

101–110 of 447 posts

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

#101
post #13

Lets take in mind that there is a problem to compare two groups when one group is much easier to measure than the other. The error interval in the mammal biomass should be much higher. The actual real values are probably not so extreme. ... I see, is just megafauna. The most competitive groups (rodents and bats) are deliberately excluded. The title is incorrect then.

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.

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.

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

#102
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…

Wow! Probably similar numbers for concrete. It's exponential growth. The thing about exponential growth is it can't continue for too long. As observers of Moore's Law will understand, eventually you run out of resources or into other physical limits. However, I'm quite confident that we can keep innovating and growth will continue in one form or another. I don't think Elon Musk is correct that human population will c…

> All it takes is one subgroup to keep reproducing above the replacement rate, and after enough generations they will come to dominate and overall growth will continue.

Consequently, religion is going to thrive. Everyone else stops reproducing once they reach a certain standard of living.

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

#104
post #54

https://ourworldindata.org/biodiversity Wild mammals: 100.000 years ago ... 20 mil. tonnes of carbon 10.000 years ago ... 15 mil. tonnes of carbon 100 years ago ... 10 mil. tonnes of carbon now ... 3 mil. tonnes of carbon https://ourworldindata.org/mammals "Wild mammal biomass has declined by 85% since the rise of human civilizations. This was mainly driven by overhunting and habitat loss." "Wild animals only make up…

Has total biomass (not just wild biomass) declined? I would expect it has, because most modern farming tries very hard to make sure the only thing growing is the thing that makes the farmer profit. A lot of farms are ecological wastelands; or rather, they sustain less biomass than they could.

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

#105
post #73

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.

Biomass is the whole mass of life beings, a standard and common measure that represents the energy contained in a particular group. Talking in terms of biomass is very common in Ecology.

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 of sound you can produce; maybe humans make up a SHOCKING 3% on that- doesn’t mean it’s a sensible metric.

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

#106
post #13

Lets take in mind that there is a problem to compare two groups when one group is much easier to measure than the other. The error interval in the mammal biomass should be much higher. The actual real values are probably not so extreme. ... I see, is just megafauna. The most competitive groups (rodents and bats) are deliberately excluded. The title is incorrect then.

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 richer than one in which bigger mammals roam: if the world’s mouse populations multiplied and multiplied – maybe even to the detriment of other animals – then this abundance metric might suggest that these ecosystems were thriving.

Instead, ecologists often use the metric biomass. This means that each animal is measured in tonnes of carbon, the fundamental building block of life.1 Biomass gives us a measure of the total biological productivity of an ecosystem. It also gives more weight to larger animals at higher levels of the ecological ‘pyramid’"

https://ourworldindata.org/mammals#the-decline-of-wild-mamma...

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

#107
post #95

Earlier quoted context omitted.

Good point about birds. Add them to amphibians, fish and insects and it would make this look less impressive.

Less impressive? Do you think there is no significant loss of biodiversity?

In the cities yes. I live outside the city. Some of the biodiversity near me is deadly and city dwellers haven't a clue.

Regardless, fish outweigh mammals by at least an order of magnitude. then calculate arthropods, mollusks, bacteria and plants and you will see this is an overstating of a complex ecosystem.

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

#108

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.

> Also, “biomass” is a strange term. Is that literally an estimate of mass? It is indeed. The idea being that individuals vary greatly (it doesn't make sense to compare individual counts of humans with individual counts of ants for example), and that mass at least roughly accounts for the size of individuals.

But, especially in mammals, it is the individual animal that is the fundamental unit. A cheetah and an elephant are unique individuated specimens; it doesn’t make sense to compare their mass. In ants/bees it’s maybe something like “number of colonies/hives” that is the meaningful unit. Why would anyone compare across species by mass- that is a reductive number, you can’t infer anything meaningful out of it. Also, certainly not by percentage - have to look at absolute numbers of meaningful units over time.

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

#109
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/

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

#110
post #37

Earlier quoted context omitted.

One day, whilst eating a burger in a pub and thinking about the food chain, I ran a thought experiment in my head. I imagined being hungry and someone offering me a choice between a ham sandwich or a vegan sandwich. I could only select the ham sandwich if I was willing to shoot a pig in the head. I wouldn’t have to butcher the pig or anything else, just be responsible for its death. I decided that I would choose the…

>It would require having 3 to 4 protein shakes a day or doing lots of cooking and prep. All the natural vegan protein sources outside of protein shakes weren’t lean; they also contained lots of carbs or fats. This made hitting macros hard. A large number of Indian people are vegetarian (plants + poultry eggs + cow/goat milk), and I've never heard of them having such problems. Why? I certainly didn't have any dietary…

Vegetarian is easier than vegan but still more difficult if you want to be lean E.g sub 15% or at the more extreme end 10% body fat. You can separate yolks and white to get lean protein from eggs. And with milk you can get skimmed milk to avoid the fat (but milk is still absolutely loaded with carbohydrates so some people argue that it is actually more beneficial to drink full fat or semi milk to buffer the carb dump somewhat.

The other thing to consider is amino acid profile. Milk and eggs have a full amino acid profile but vegan sources are normally incomplete. This means to get all the protein your body needs you have to consume multiple protein sources. And bioavailability: just because you consume 1g of protein doesn’t mean your body can necessarily use that entire gram. Vegan proteins tend to have the lowest bioavailability, often in the 0.7 to 0.8 range meaning you have to consume more of them for the same result. Which is problematic as it means you’re now consuming more carbs and fats knocking your macros further out of whack.

It is doable, it is just very hard work. Here is a vegan bodybuilder with 13.7% body fat percentage after 4 years.

https://www.menshealth.com/nutrition/a33807797/bodybuilder-v...

The other thing complicating matters nowadays is steroids, SARMS and TRT. If people are on them it makes life significantly easier: there were studies done that showed people on steroids doing absolutely nothing (no workouts whatsoever) still built more muscle than people who were natural (no steroids) doing hours of hard bodybuilding gym workouts. They are absolutely rampant, far more than people realise. For what it’s worth looking at this guy, I don’t think he’s doing roids. His physique is achievable without them. But I might be wrong.

Also, heart disease is absolutely rampant in India. So not the best country to be using as an example.

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