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Comment by bubblewrap | Hacker News Reader

My favorite doomsday scenario at the moment is that it may be earthworms who finally kill us: https://www.nytimes.com/2019/05/20/science/earthworms-soil-c...

They appear to be venturing into new areas and releasing carbon there, furthering global warming.

There are just too many scenarios of that kind.

Either we really are doomed, and climate will switch into a new kind of equilibrium hostile to humans.

Or, there are lots of mechanisms in place that counteract against such effects, and which are not yet well understood.

With so many climate based doomsday scenarios, how did earth survive for so long? I think there have to be at least some regulating mechanisms.

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> Will so many climate based doomsday scenarios, how did earth survive for so long?

See the other 5 mass extinction events.

I think they were more driven by biological evolution than by climate change, though. At least some of them (Cambrian, maybe also Dinosaurs).

Humans are actually very adaptable to all sorts of climates. They've lived in the arctic and in the Saharah.

Also, mass extinction events OK, but we are talking about a runaway effect of heating up the atmosphere, turning it into a Venus like planet. That doesn't seem to have happened before.

> Humans are actually very adaptable to all sorts of climates. They've lived in the arctic and in the Saharah.

Lived? Yes. Thrived? Not so much.

A Saharah like climate won't feed 7.5 billion people. If the population crashes to a few million stragglers living mostly at the poles then we'll regress back to the stone age.

There may be no way yet to support 7,5 billion people on renewable energy. Then what?

Also not saying everything will become like the Saharah. Just that humans may adapt better than those animals who died in mass extinction events in the past.

earth will survive just fine. its habitability for humans and other current life on the other hand...

Humans seem to be very adaptable, though. They live in all sorts of climates.

I would add ... and other current life, including life on which humans depend, for which humans have already contributed to their extinction independently of climate change (see 75% loss of crop diversity in a century as posited by the FAO).

These doomsday scenarios have happened before. There are mechanisms that quickly bring things back to normal. Unfortunately, “quickly” is on a geological scale. An 8°C temperature raise for 100,000 years would be rather problematic for humanity.

> Will so many climate based doomsday scenarios, how did earth survive for so long?

Earth will be fine. Us, not so much.

Depends how you define the earth being fine.

Not cracked in half or pummeled to space gravel.

But even if you wanted to be less strict, life on Earth will be fine too. It's humanity - and in particular the technological civilization - that's in danger.

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