I’m curious how we are sure that we aren’t under sampling? The climate data sample frequency I’ve seen from the distant past has not been on the order of decades or even single centuries. Is it possible that there is sometimes a natural higher frequency temperature oscillation that doesn’t show up in the natural records with our current techniques?
If the present Earth continued warming for the next 50 years and then cooled down again, would we expect to see an extinction event in the fossil record, if we ignore human impacts other than temperature? I think the temperature change would have to be larger for that to happen?
I'm not saying this is what is happening, or commenting on how likely it is, I'm just not sure why everyone seems to be ruling it out completely and I would like someone to fill me in.
Over the next 50 years? Yeah, almost certainly. If the current change continues for the next 50 years, you’re going to have ecosystems changing _dramatically_. Of course, it’s kind of speculative, as you _can’t_ really disentangle the other effects of humanity easily, but if the current trend continues for another 50 years, it’s hard to see how that would not lead to a mass extinction event.
> I'm not saying this is what is happening, or commenting on how likely it is,
I mean, I think we can say that is _definitely_ not what is happening right now. It is not just doing it on its own. Like, what would the mechanism be?
We like to feel so important. And we are. But rooting for Team Earth to spread out beyond our planet gives me some comfort, rather than the existential horror of cosmic time scales relative to human lives. That’d be a bit like a fruit fly pining away that it only lives a few dozen hours, which must feel like a lifetime to it.
Other mass extinctions with different potential causes took longer.
Most mass extinctions and climate change occur over much longer time periods than the human eprochs climate change is occurring.
Basically, think of the collective action of genetic adaptations over successive generations as a computational problem where biology is adapting to climate.
From what I've read about the science of the chuxulucub impactor, the resulting mass extinction still took over a time period of a million years.
But humans are imposing a series of climate changes and ecosystem disruption that exceeds the ability of generationally adaptive natural selection to adapt to, because we are introducing massive changes not on the scale of millions or even hundreds of thousands of years, but just a couple hundred.
And of course what is most important, selfishly, to humans is that we have a planet that will support US. So while life may have survived the introduction of oxygen into the atmosphere and numerous other massive changes in Earth's ecosystem, we likely would not.