Ask HN: What would be the effect on our earth if humans would disappear? | Hacker News Reader

Ask HN: What would be the effect on our earth if humans would disappear?

Recently I came across several discussions about eradicating mosquitoes - reasoning that the world would be a better place without them[1] - even though in some climates they are crucial for survival of other species.

[1] http://www.nature.com/news/2010/100721/full/466432a.html

I tried to find content about how relevant humans are to other life forms on earth and wonder what species (if there are at all) is totally dependent on humankind and would go extinct if we would vanish from the face of the planet?

This is probably a silly (and somewhat morbid) question. Yet how important are we to the ecosystem? Or have we managed to detach ourselves so far from mother nature during the course of evolution that we no longer matter?

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Cows and chickens might have a hard time of it. For everything else, life would absolutely flourish, even as the nuclear reactors melted down one by one. I can't tell if your post is intentionally ironic, but the main impact we have on most life on this planet is to destroy it.

There are wild cows and chickens. Most domesticated ones might die, but they'd largely just revert to pre-domestication levels and modes of living.

Quite a lot of species were destroyed as part of the evolution process.

We are 'important' in the respect that we continuoulys disrupt and manipulate our ecosystems. For example, we directly and indirectly continuously hunt down other apex predators (tigers, lions, tuna, etc) - which tend to be keystone species in their environment. Removing that pressure on those species would nearly immediately modify the environment. For an example, look at the reintroduction of wolves to yellowstone.

Nearly all species that we have domesticated will suffer ridiculous drops in their population. Many of them would be reduced to severely reduced niches. For example, domestic cats would have their ranges limited by winter, and have downward pressure applied from larger predators as they rebound. On the other hand, based on how well feral pigs are doing right now, pigs will probably make it huge.

There was a book about this a few years ago: http://www.amazon.com/The-World-Without-Alan-Weisman/dp/0312...

"Life after People" describes this exact scenario over 20 episodes.

From http://en.wikipedia.org/wiki/Life_After_People: Life After People is a television series on which scientists, structural engineers, and other experts speculate about what might become of Earth should humanity instantly disappear. The featured experts also talk about the impact of human absence on the environment and the vestiges of civilization thus left behind.

Disastrous. Thousands of container ships drop their cargo into the ocean. Oil platforms corrode and begin to leak uncontrolled. So do chemical plants all over the world. Nuclear power plants meltdown. Huge fires in cities all over the world burn uncontrolled, releasing tons of ash into the atmosphere in a short time period.

In the long term, invasive species we've already introduced take over. Domestic animals like cats and dogs will kill off most the wildlife before starving to death.

https://en.wikipedia.org/wiki/The_World_Without_Us

I just saw this video earlier today: http://www.dailymotion.com/video/x276y8d_et-si-l-humanite-di...

It makes me realize that temperature would slightly go down since we won't heat and pollute our planet anymore!

If humans would to perish. Animals threatened of extinction such as the Tigers, rhinos would be saved. World fish populations and sharks would be restored. Rain forests would be saved. The air quality of the earth would be cleaner. Global warming would stop.

In short human sucks for most other species on earth as we behave now.

Mostly right, except for global warming. Although it's proven that it happens, it's still yet to be proven that humans cause it, or what part of it is caused by humans.

The main change, as I see it, would be a sudden dramatic reduction in the amount of carbon dioxide entering the atmosphere. Humans burn fossil fuels. That would stop.

What the downstream effects would be and how quickly they would happen, I don't think is easy to answer.

>> The main change, as I see it, would be a sudden dramatic reduction in the amount of carbon dioxide entering the atmosphere. Humans burn fossil fuels. That would stop.

That's assuming we disappear into oblivion w/o having to decompose or otherwise ignoring biological/chemical reactions that usually follows our death ...

I have no specific insight but we stopped being a significant part of the food chain a long time ago, in some relatively miniscule amount of time it'd probably be just like we never existed. Or barely.

Are you saying we stopped eating?

We stopped being eaten - the only animals that depend on us are domesticated or chickens/cows/etc as another poster mentioned.

> it'd probably be just like we never existed. Or barely.

The Anthropocene would leave a distinct layer in the fossil record.

http://www.economist.com/node/18741749

What kind of time frame would be required for that (and all the other evidence) to become uninterpretable - knowing we did exist, but not much more. Is there an amount of time where there'd simply be no evidence at all?

Edit: Found this which I guess is our limitation at least, though perhaps not our successors.

    The oldest known fossils, in fact, are cyanobacteria 
    from Archaean rocks of western Australia, dated 3.5 
    billion years old. This may be somewhat surprising,
    since the oldest rocks are only a little older: 3.8 
    billion years old! Cyanobacteria are among the easiest
    microfossils to recognize.

http://www.ucmp.berkeley.edu/bacteria/cyanofr.html

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