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Post No.: 0071extinction


Furrywisepuppy says:


As a consequence of not compensating nature enough for the things we buy and do, and not living in harmony with nature, as discussed in Post No.: 0055we are strongly arguably in the midst of causing, via our own actions, directly or indirectly, the 6th mass extinction event in the Earth’s history because we’re vastly reducing biodiversity in a short timescale (note that one or two thousand years is incredibly short in geological terms) across a wide range of ecosystems (e.g. marine, jungle, forest, coastal). In this (currently unofficial) ‘Anthropocene epoch’, humans are changing the global environment extremely rapidly in a number of ways (e.g. claiming land and freshwater for our cities and farming, viral or bacterial epidemics from livestock or air travel, poaching, deforestation, emissions and global warming, CFCs, nuclear waste, fracking, oil spills and other disasters, etc.). It is arguably the Anthropocene epoch because human activity is clearly the dominant influence on the planet’s environment and climate right now.


The success of one species – the archaeopteris tree – is considered to have been the major contributor to the End Devonian mass extinction. This can be likened to the ‘success’ of the human species wreaking havoc to ecosystems around the world today and causing multiple species to go extinct. Even though humans live in diverse environments on Earth, species that did so before still became extinct from global events. Now it’s important to note that the planet will very highly likely be fine and will carry on, but the human world will likely not. A loss of biodiversity means a decreased chance of nature and life on Earth in general finding a way to survive after a catastrophic effect (it’s akin to having eggs in too few different baskets). Destroy biodiversity by destroying other species and habitats (e.g. flowering plant meadows for bees) and we destroy our own lifestyles or civilisations down the line too. This ‘6th mass extinction event’ is predominantly being driven by human activity – habitat loss, habitat degradation, habitat fragmentation, invasive species (e.g. as a result of trade stowaways, the meat industry), pollution, contamination, climate change, poaching, trawling (including unintended life getting caught in fishing gear), and so on.


5 known major extinction events have happened before according to studies of fossils and geology (Ordovician, Devonian, Permian, Triassic and Cretaceous). Like after these previous events so far, biodiversity will likely eventually recover again after the 6th event – but will humans still be here? According to the previous 5 major extinction events, there’ll be a ‘changing of the guard’ of species that’ll flourish, as it were, as the dominant species of the time goes extinct to make way for new dominant species – and humans like to consider themselves the (one and only) dominant species right now; and in this context of the impact on this planet this seems to be incontrovertible.


Of course, a background rate of extinction is always occurring too, and this rate seems to be about 10-20% of species every 1,000,000 years on average – but the ‘Big 5’ killed off at least 50-75% of all contemporary species each time. (These may be conservative estimates too because we don’t know how many species we haven’t found or will never find because they left no fossils or those fossils were destroyed via geological processes over time.) So the rate that species are currently going extinct is far greater than the background rate of ~1-5 species per year according to historical records. And some biologists estimate that 50% of all current species will be extinct within 100 years, which is entering the region of the mass extinction events of the past.


So if the past predicts the future then things don’t look good. Some people look too myopically e.g. when comparing past human technological disruptions to upcoming ones and thinking that the past predicting the future means the future is always going to be rosy or fine. According to this evidence – we wouldn’t want the past repeating itself when we take a less myopic look!


Yes, fossil records are limited though, hence we don’t really know for sure how many species existed in the past to know how many had therefore died out, but what we do know is that 5 major extinction events have happened in the past so far because they stand out abruptly and starkly in the fossil records, and we are seeing an increasing and sharp rise in the number of species going extinct since human industrialisation too. It’s also true that we don’t know of all the existing life that’s on the planet today (deep sea marine life in particular) but that’ll only mean that any extinction counts today are likely going to be underestimates – we won’t know what we’ll have lost if we didn’t know they existed in the first place. Woof.


The current extinction rate of species surpasses normal background rates of extinction, and in the case of vertebrates, as much as 100 times higher (and vertebrates are the group that we’re most confident of understanding in the fossil records because they leave bones that fossilise hence we can compare today’s extinction trend to historical trends according to vertebrate numbers). In only 300 years at this rate, it is inferred that 75% of all species will go extinct. As human populations have increased, the extinction rates of other species have correlated, and many of the causal arguments are hard to scientifically dispute.


The loss of vertebrates has knock-on effects on the entire ecosystem (e.g. wolves and their effect on the courses of rivers, fish stocks actually increase when there are more whales in the waters). Over-fishing harms seabirds too because they depend on the fish as food too – an effect in one area has knock-on effects throughout the food chain. So we must think in terms of ecosystem-wide effects (trophic cascades) and concentrate on whole habitats, not just single species or singular effects. Concreting over pastures, clearing forests to make way for grazing land for grazing animals for the meat industry or for growing biofuels, or whatever we do on such a large and rapid scale, whether for economic or political reasons, tends to have unfortunate knock-on effects on wildlife. Via market forces and market efficiency, 90% of our food starches come from only 10 plants, but in the bigger picture and longer term this reduces biodiversity. The same with the medicines we use. Farming can keep those species that are farmed sustainable but it can be at the expense of habitat loss for multiple other species. This reduction in biodiversity due to mono-agriculture/monoculture farming may harm our own long-term interests too (e.g. we’ll have fewer plants to discover future medicinal ingredients).


So if people argue that the things that we are doing right now or in the near future will automatically be fine because ‘things have always turned out fine in the past’ – then no, things haven’t always worked out fine, particularly for the dominant species of the time. If it follows the previous ‘Big 5’ then biodiversity will eventually one day return (in geological timescales i.e. we’re talking about thousands to millions of years) – but with a very different biodiversity than today, and with the dominant species of the time getting replaced. Hence if the past is the best predictor of the future then the human race is right on course to being screwed soon, in geological terms. Humans are creating a global climate that even humans have never actually lived through before in the species own history! This planet will likely be fine again after the dust settles but humans likely will not. Maybe a smarter, more considerate and respectful species than humans will then inherit the Earth?


Woof. Whether we all look after this planet better or try to look to migrate away from this planet, or both in my furry view because we may never find or create anything quite like Earth and living in space is extremely difficult (you may guess that I’ve studied that subject too) – we cannot just carry on and bury our heads in the sand, cross our fingers or appeal to history. Predicting the future is always fraught with a degree of uncertainty but when the potential costs are this high, and the current evidence around the world today is this strong, it’s irrational to fail to appropriately act. Not all fears are alarmist yet it’s not doom or gloom yet. It’s probably not too late yet to steer ourselves onto a more sustainable path but we must all make some drastic changes to our attitudes and lifestyles right now. Fluffystealthkitten and I are still upbeat for the challenge! Are you?


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