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Comment by swalling | Hacker News Reader

“On average, more than 50% of the increase in exposure projected for a species will occur in a single decade.”

In other words, expect extinction events to happen very abruptly and cascade across food chains.

Today people are generally not noticing the current global extinction event because of the way that your perception of “normal” diversity in species is set psychologically. If warming really causes rapid die offs on the order of decades however, the current mass extinction will suddenly feel very apocalyptic, by which time it will be too late to save any species that isn’t capable of radically shifting its own habitat range and food sources (i.e. raccoons will probably be okay, polar bears are toast).

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An analogy I heard is of a slow motion train crash - our carriages somewhere in the middle of the train are so far seemingly unaffected, but already the first carriages are crushing, and people/animals/life is beginning to flee backwards on the train as best they can. For us in those middle carriages that will be the first first-hand indication of the catastrophe. Following this analogy, it is too late to stop the train crashing, though maybe we can slow it down and save as many of a carriages as we can.

The location of your specific carriage is also geographically and economically dependent on your personal situation. Your carriage crash will be studied, the results added to others, while we procrastinate and prostrate to capitalism, begging it to save us, when it's really the cause of the crash to begin with.

Yes. This is "the future is already here, it's just not evenly distributed" but applied to climate crisis and mass extinction. Pakistan already feeling the train wreck, whereas US, Canada etc. are still somewhat insulated by wealth so they can ignore the obvious.

yes agree, but let's not be too broad. The way forward includes careful attention to detail, least we miss chances to act or mitigate. A trivial example is that "polar bears are toast" .. no actually, some recent good news about a remote polar bear population came through.. but how could a non-specialist know that? we have to value reliable networks of information. less drama, more reliable, right?

mass-media is not going to be useful for this, and actually counterproductive for emotional health..

> no actually, some recent good news about a remote polar bear population came through

Source? Even with short term fluctuations, when the sea ice is gone, polar bears are fucked.

I might be mistaken, but they could be referring to polar bears seen surviving for a long time without much sea ice, further south than usual in Greenland.

The thing worth noting here is that this means we’re seeing polar bears as we commonly recognize them still going extinct. What will survive will be an offshoot of them which survives by different means in different environments. So I’m not sure it’s actually good news about polar bears more generally.

I think if humans give up on the mistaken idea of species as a fixed concept rather than an evolutionary line, then it's fine. What matters is that a healthy ecology which supports the largest land predator on Earth persists.

The thing we're trying to avoid is a repeat of the Permian–Triassic extinction event, where afterwards Lystrosaurus composed 95% of land vertebrates for millions of years. Domesticated animals already compose a massive proportion of the bird and mammal biomass.

Polar bears without ice and snow will become brown bears. Polar and brown bears can cross breed. My guess is that the polar bears will merge and turn back into brown bears. But polar bears will be gone.

This was my intuition as well. The several-hundred year old populations haven’t become brown bears yet (not sure if they’re present in that eco system), but it seems likely that this would be inevitable on a long enough time scale. Having said that, I should also point out that I don’t know anything about any of this.

The barrier to this is dietary diversity. Brown bears are among the most omnivorous large mammals, whereas polar bears only eat plant matter in limited amounts / specific locales. A brown bear will get fat on food a polar bear starves on. You can’t reproduce if you’re not well fed.

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