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The Sixth Mass Extinction: fact, fiction or speculation?
- thrown_22 5y agoOne thing we always see when a mass extinction happens is that mega fauna goes first. Large animals can't hide, unlike rat sized ones. Currently so much of the mega fauna outside of Africa has disappeared that we don't even think most continents had any: https://en.wikipedia.org/wiki/Megafauna#Megafaunal_mass_extinctions https://en.wikipedia.org/wiki/Megafauna#Megafaunal_mass_exti... That would suggest we're 10,000 years into one, rather than being at the early stages of it.
- pvg 5y ago10k years is not a lot of geological time so even if true, that could still well be in the early stages of a mass extinction.
- darkmarmot 5y agoWhen humans killed off most of the megafauna, it caused cascading extincations. Dire wolves went extinct with nothing to eat. The Osage orange tree nearly went extinct (down to one very small area); it's believed that were spread by Giant Ground Sloth droppings. Tons of dependent plants and animals likely vanished from our "natural" landscape without ever having been recorded.
- blueprint 5y agowhat megafauna did humans kill off, which you're referring to? there are rumblings that the ~10k year ago megafauna die off was far too rapid to have been done by relatively unsophisticated humans and is likely to have been caused by a comet fragment impact or similar. https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesis https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesi...
- slater 5y agohttps://en.wikipedia.org/wiki/Megafauna#Timing_and_possible_causes https://en.wikipedia.org/wiki/Megafauna#Timing_and_possible_... ¯\_(ツ)_/¯
- meristohm 5y agoUnsophisticated humans? We haven’t changed much in the last 50,000 years, from what I remember from Sapiens by Yuval Noah Harari. My feeling is that our collective ancestors were creative, intellectual, observant, and all the other positive descriptions we might aspire to, along with being brutal killers fighting to survive. In the span of a couple hundred years we’ve engineered global climate change—-that’s impressive and disheartening, and adopting more of the leave-less-trace existence of our ancestors might be prudent.
- kuhewa 5y ago> We haven’t changed much in the last 50,000 years Genetically, not too much. In terms of population density and technology, we absolutely have changed, and both are relevant to our ability to clear a continent of dozens of species of animals at a rapid rate.
- blueprint 5y agotechnologically unsophisticated. no guns. hard (or impossible) for them to have wiped out a continent of megafauna in the timespans that had previously been suggested.
- robbedpeter 5y agoHumans being the cause is speculation, not fact. It's worth looking into the alternative theories and making your own judgment based on available evidence.
- thrown_22 5y agoThe alternative is that all mega fauna survived a dozen ice ages over the last 5 million years, only for all of them to go extinct when fully modern humans finally invent agriculture by sheer coincidence.
- cultofmetatron 5y ago> Why is Africa, the place where humans have been the longest, teeming with megafauna? Because they evolved with us and evolved to respect the threat we pose.
- meristohm 5y agoYeah, and I think this is noted in The Old Way, by Elizabeth Marshall Thomas.
- oh_sigh 5y agoWhy is Africa, the place where humans have been the longest, teeming with megafauna relative to the rest of the world? Why did megafauna die out in regions where there was little to no human presence? Maybe the environmental conditions that allowed for humans to invent agriculture also spelled doom for the megafauna. If the world of relevant scientists agree that this is an open problem, it doesn't make sense to just pretend like we know the answer because it suits us in whatever manner. The fact is: We don't know what killed off the megafauna.
- colordrops 5y agoWe do in some cases though. The bison in the US were definitely killed off by European settlers. Rhinos in Africa were killed off for asian medicinal customers.
- prescriptivist 5y agoThe blitzkrieg hypothesis is hardly settled science. Don't know why you are so confident this is what happened.
- throwanem 5y agoYes, that's what we always see, because megafauna are highly obvious in the fossil record. Tiny or especially soft-bodied invertebrates maybe not so much, and I'd hesitate to assume past mass extinctions provide too precise a model for one taking place in the present day. After all, there's nothing in the fossil record to suggest what a mass extinction might look like like in an environment containing modern humanity, too.
- 37 5y agoSo how long until it becomes a REAL problem for humanity? A couple thousand years? (if we are already 10k years in)
- tjr225 5y agoAre abstracts typically filled with this much editorial? I’m no climate science denier but adjectives like “sad” seem insanely out of place in something like this…
- kingkawn 5y agoit is sad that we have done this to the world.
- tjr225 5y agoI agree; but is sadness any sort of scientific measure? Does it have any place in an abstract or a scientific study? I don’t think so. It seems weird to me.
- kingkawn 5y agoThere is no gain from rejecting different types of truth that don’t adhere to a single way of producing it.
- ppqqrr 5y agoIt’s a three-letter glimpse into what motivated these scientists to write the paper; I think we can acknowledge it and move on without losing sight of scientific rigor.
- kuhewa 5y agoTt appears to be a pretty sound review of evidence, and then a discussion and conclusions section where the results of the review are interpreted and implications are discussed. Seeing "sad" appear in an abstract is sort of unusual. However in the discussion in the review the arguments about morality etc are a bit more sophisticated, but I reckon it isn't too odd to have a value claim on the implications of the review being unfortunate, since they have real implications for human wellbeing. If the same sentiment was couched in normal amounts of academic jargon, you would likely not have noticed.
- timbit42 5y ago
- mistrial9 5y agospoiler: FACT
- deleted 5y ago[deleted]
- AtlasBarfed 5y agoYeah in my life I've seen 100-odd headlines about extinct species, and I'm not a naturalist or similar news subscriber. But by all means, let's waste another 10 years sending it back to committee, for review and debate and bikeshedding semantics.
- betwixthewires 5y agoI'm curious if you've ever dismissed someone else's statement as anecdotal.
- AtlasBarfed 5y agoSpecies extinctions aren't anecdotes.
- betwixthewires 5y ago"I've seen 100-odd articles about extinctions in my lifetime" is absolutely 100% an anecdote.
- MattRix 5y agoWhat kind of bizarre argument are you even trying to make? Just say what you want to say in plain English.
- betwixthewires 5y agoAre you joking? My statement is plain as day. Claiming "I've seen such and such" is the textbook definition of the word "anecdote". Using that to justify a position is what we (all) call "anecdotal evidence."
- deleted 5y ago[deleted]
- another_story 5y agoWouldn't it be best to act as if it's fact, even without definitive evidence one way or another? Otherwise it's like deciding to not drive cautiously on a mountain road because your GPS isn't sure if there's a sharp turn ahead.
- quaintdev 5y agoWell the pandemic has shown us that even if the GPS is pretty sure there is a sharp turn ahead some people refuse to believe it because it is scary to drive on that sharp turn. Eventually we all will have to take that sharp turn but I just hope there is safe passage left ahead of that turn and not all downhill.
- colechristensen 5y agoThere will always be another thing to be afraid of. “ Wouldn't it be best to act as if it's fact,” will always be there as a question for the next thing. So no, it wouldn’t be best to default to assuming the worst, you have to be able to decide which risks to tolerate and which to address, and to which degree.
- ouid 5y agoAbsolutely not! The only way that you can believe this is if you a) consider the preservation of human civilization to be approximately equal, in terms of significance to your decision making, to living a more comfortable life personally. In this instance, we are at war, and I have nothing to say to you, so you can stop reading. Or b) you are making a very serious error in your calculation. Imagine that you the kind of immortal being that can still die in car crashes, but you never age. Whenever you take a risk, of death say, in order to get the expected utility of taking this risk, you need to multiply your risk ,which is a small number, by the opportunity cost of that risk, which is an infinite life's worth of utility. I do not, like many of the "rationalists" believe that this figure is infinity, but it is very obviously much larger than your risk is small. It's hard to reason about, but I urge you to imagine it in the shower with the lights off. Really try to get into that space, and imagine what risks you would consider to be acceptable as an immortal. Humanity is such an immortal being, but it currently lacks the tools to act for itself. We can build those tools, but that will take time and lots and lots of thought.
- eucryphia 5y ago
- jimmyvalmer 5y agoThat book really hit home for me the insignificance of human versus planetary timescales. For all our handwringing about global warming, we're actually in an ice age. Even if we solve climate change, the earth will continue to witness unfathomably long geologic eras long after we're gone.
- tehjoker 5y agoYes and no. The planet is middle aged. If we burn everything down to nothing again, the Earth only has one or two regenerative cycles left (where it can go from simple organisms up to things as complex as mammals again based on how long that took) in it before the sun's slow increase in brightness evaporates the oceans making complex life impossible in about 1.1 billion years. We can really do some damage to the lifecycle of this planet. It took about 2 billion years to go from RNA world to today. https://en.wikipedia.org/wiki/Future_of_Earth#Loss_of_oceans https://en.wikipedia.org/wiki/Future_of_Earth#Loss_of_oceans
- jimmyvalmer 5y agoCall me an anthropomorphic narcissist, but I can barely manage concern for my descendants a hundred years from now, much less the carbon-based morlocks scampering around a hundred thousand years from now.
- tehjoker 5y agoWhile it seems likely life is located elsewhere in the universe, it seems to me we should be good stewards of the one little mote of dust where we know for sure it exists.
- jimmyvalmer 5y agoI don't have a particularly good grip on how long a million years is, but I suspect it's still better than yours. A million years is less than a week in the Earth's lifetime. The virus of humanity can do its darnedest but the planet isnt going to remember a mild cold.
- titzer 5y agoWhen I was a kid, I always thought that where I grew up (southern Indiana) was basically a forest and that the farms and towns and roads that I saw were just "nestled" in the forest. That's because everywhere you look, there's almost always a line of trees on the horizon. Not being particularly mountainous, or even hilly, it looks from a distance like the tree line is the "forest". In pretty much every direction. I was a boy scout, and we did a lot of camping at various parks. I really didn't know exactly where I was, I just thought we were out in the "forest". It's a trick of perspective. I had never really seen my local area from the sky until about 2000. Now, Google Earth can show you the whole thing, at zoomable resolution. Boy, was I wrong. Not only is southern Indiana mostly not forest, it's mostly farms, roads, and fields, and towns, with only scattered lines and splotches of trees. In reality, those boy scout trips were basically in nature preserves and national forests, the few remaining places of actual forest. Human habitation has absolutely decimated the forest...across the entire midwest. And the many millions, billions of animals that lived in the forest, they're gone, numbers dwindled, or exinct. Bears and big cats and wolves and elk....almost all gone here. Not to mention the intricate ecosystems full of life, from squirrels down to insects and ants...uncountable the individual living things that have been absolutely obliterated by our hunger. Just take a look at Google Earth, switch to satellite mode, turn off all labels, and take in the vast green patchwork of farms that stretches for a thousand miles in every direction in the middle of North America. There is precious else but farm and city and road.
- eggsmediumrare 5y agoA lot of my social circle is farmers or children of farmers, and they almost universally consider the farm to be "nature" or at least a close enough thing to nature. I think society just kinda decided that nature is "not city" and that attitude is holding back progress.
- nr2x 5y agoHighly recommend reading Kolbert's book.
- lettergram 5y agoI like to bring this up, but 8,000 years ago half of North America was under ice. That means that every living creature in that region didn’t exist. Every creature unique to those regions came about in the last 8,000 years. 1. I think evolution happens much faster than people realize 2. Extinctions happen more quickly than people realize 3. Humans likely were the cause of many extinctions through pollution and cultivation. But other animals and plants are currently filling the niche and containing to expand. I would really like to understand the distribution of species over the last 10k, 100k, 250k, 1m years. We simply don’t have great data so it’s really hard to say. What I can say, is that there’s a ton of life. Life doesn’t appear to have diminished much on a whole. Which is comforting, at the very least.
- Maursault 5y ago> Life doesn’t appear to have diminished much on a whole. There are a lot more humans now, and a lot more cows, sheep and hogs. There's much less of everything else, from the bottom on up. I think where it is easy to see is in the drastic decline in small and large mammals, other than humans, cows, sheep and hogs. Once you see that, maybe you'll notice, just in your own lifetime, the massive decline in bird species and populations. Maybe you'll notice when you drive around at night in the Summer you no longer have a windshield covered in dead bugs. I haven't see a real frog in years. Unless you're satisfied with merely diverse species of bacteria and other simple life forms for the next X billons of years, you should be startled at how astoundingly quickly Earth's amazing diversity of life has declined from whatever it's most recent peak was before the development of civilization, or before the Babylonians, before the Greeks, before the Romans, before the Industrial Revolution, and before the Chemical Revolution. Don't you ever wonder just how many whales there were before the first whalers? Or how many tuna or salmon there once were? Reports from Colonial times on bird populations aren't very specific, but at certain times of years, the number of geese alone in Virginia used to darken the sky. They didn't just shoot down one goose at a time, they used giant guns that took hundreds at a time. Maybe we don't do it with big guns, but we are basically poisoning everything on the planet to death. So maybe the amount of biomass stays the same, but who wants a planet of poison goo?
- kuhewa 5y ago