Global warming- If we cause our own extinction...

Great Debates
1

If we cause our own extinction, will the Earth recover? Extinction of a species is not a new thing for this planet, and rarely will climate change cause a mass extinction. A series of warm and cool periods in the past have caused the extinction of certain species, depending on their habitat requirements, but these events have not caused extinction on a global scale. Total extinction of all species on earth is not going to be caused by climate change.

Now, let’s assume that we deforest and pollute the planet so much that we begin to kill ourselves and many other species over the course of many centuries. It’s a bit extreme to say that a system as dynamic and complex as the earth will not recover when the cause of this problem (us) is gone. Sure, the planet may look bad in the time immediately after we force ourselves extinct, but remember that the earth is 6 billion years old, and life has been present for only a fraction of that time. Humans have been here for an even more minute amount of time. Will a planet that supports liquid water and the creation of oxygen be changed by humans to such an extent that no life will be able to flourish once we are gone?
If we ever do kill ourselves by making the planet uninhabitable to humans, will the planet likely recover in only a few thousand years, which on the scale of time for the earth’s existence is a mere millisecond?

2

I would imagine it would take less time than that. Life finds a way to live in some pretty unhospitable environments.

It is highly unlikely that we can make the planet uninhabitable. What people are worried about is making conditions such that it wouldn’t be able to support all the humans that are currently here.

3

Even the most extreme environmentalists agree global warming won’t cause our extinction. It will cause massive hardships – many existing cities will be flooded underwater, millions of deaths, refugees uprooted, worldwide political destablization, etc; but human beings will not die off completly. Life will continue in some form, both for humans and for all other animals.

4

4 billion.

The earth has suffered thru much worse than global warming, but then it probably would take much more than global warming to cause our extinction. And it depends on what you mean be “recover”. It won’t be the same, but we’re not going to wipe out all life. There are plenty of species that are less fragile than our own, and those species would pick up where we left things off. Who knows if sapient life would evolved again, though. We only know of that happening once.

5

4.55 billion. But, who’s counting?

6

Yes, but it’s been telling everyone that it’s 3.9 billion years old for the last 650 million years. It’s a little sad, really.

7

People that claim to know what our planets condition in are just nuts. We have been on this earth for a very small portion of its existence, and we are only beginning to understand it.

8

Ya know, I knew someone would come along and do that if I didn’t take the time to look up the age more accurately. That’ll teach me for being lazy… :slight_smile:

Can you clarify what you mean and how it relates to this thread? I’m honestly unsure what you’re trying to say.

9

And life has been around for 3.5 to 3.7 Byr, with many notable mass extinction events; at least six in the last 500 Myr: the Cambrian-Ordovician, Ordovician-Silurian, Late Devonian, Triassic-Jurassic, and Cretaceous-Tertiary events. In addition, there is a predominant opinion amoung biologists that we are currently going through a mass extinction event commonly called the Holocene Extinction Event, although the scale of the event and the degree to which anthropomorphic impacts (from pollution, encroachment and environment erosion, climate change, et cetera) contribute to this are subject to debate, although it’s pretty clear in many recent cases that human influence has been the primary factor in the extinction of species.

For climate change to cause extinction of the human race some secondary impacts would have to occur, i.e. prior extinction of some keystone species. Since we have such a capacity to manufacture artificial environments in which to raise food and other perishable necessities it seems unlikely that such an even could occur, though certainly the impacts of even a modest degree of climatic disruption could have severe consequences on modern civilization, forcing humanity to alter the way it functions within both local and global ecospheres.

It might have long term positive consequences as well; a concept that climate change zealots almost universally fail to acknowledge. While species extinction–especially that caused by unintentional residue of human action–is regarded as abominable, it’s also a regular part of the natural cycle of evolutionary development, and subsequent to every major extinction event a profusion of new species, genera, families, and so forth on up to phyla has emerged, often with more sophisticated and refined phenotypical capabiltities.

Mankind couldn’t kill off all life if it tried. It seems unlikely it could even directly eradicate itself.

Stranger

10

Recover from what? There is no such thing as ‘normal’ for our or any planet. It has been evolving since birth and will continue to do so. Any changes that bring about our own extinction will simply be another state of existence for the earth as a whole. As an entire system it won’t be ‘sick’ or anything for there to be any need to recover. It will simply be different.

What is good or bad simply depends on your point of view. From another perspective mankind could be considered the ‘sickness’ and our extinction be considered the recovery!

11

Yes, but doesn’t it count for anything that “different” means “crappy for humans within the foreseeable future?” Are we so stupid that we’ll shit in our own house and say “oh well, climates change?”

I don’t care that the atmosphere was pure nitrogen for a billion years. I live here now, I find the climate agreeable, and I see no reason to rush the earth to its next human-hostile transitional stage.

12

I don’t disagree with you Brain, but the OP isn’t about that.

13

All I know is if I’m about to be extinct, I’m taking everybody with me.

14

More of a debate than a question with a nice, tidy factual answer. MOved to GD.

samclem GQ moderator

15

The result might turn out something like this.

16

IIRC, mass extinctions always take a minimum of ten million years or so to recover from.

Or we’d have to push things so far that Earth went into a runaway greenhouse and ended up like Venus.

Yes, in ten million years or so. Why should anyone have more than a scientific interest in that ?

A runaway greenhouse effect would do it, as I said.

Humans and animals have the only point of view there is. The animals won’t like suffering and dying even more than they are now, and neither will we. Besides, humans as a species are very adaptable; destroying civilization is one thing, but actually killing off all of humanity would probably require something that would kill off most other forms of life along with us. Or just plain kill everything; Earth wouldn’t recover from a runaway greenhouse or runaway ice age; Venus hell-planets and Mars-style iceballs are stable, and can support little if any life.

17

If we manage to make the planet uninhabitable for humans, who are capable of surviving (by artificially modifying habitats) in Antarctica in mid-winter, in the Sahara in mid-summer, and underwater, then the corresponding extinction of other species which lack this capability will make the Permian mass-extinction event look like the Garden of Eden. It would take many millions of years to recover equivalent levels of diversity and complexity after such a catastrophe.

18

6000

d&r

19

Let’s get an idea of the scale of what you’re talking about here. The atmospheric pressure of Venus at the planet’s surface is 92 bars and it’s 97% carbon dioxide. On Earth, pressure at sea level is roughly 1 bar and about 0.04% carbon dioxide. We’ve got a long way to go before we’re even close to a “run-away greenhouse effect” as observed on Venus.

20

It’s very unlikely that we could cause our own extinction through climate change.

Probably the most likely method for causing our own extinction would be a super bacteria created for the purpose of biological warfare (we’ve already done some pretty nasty stuff in re bio weapons, imagine what a few hundred more years of technological advances might give us!)

Many scientists now believe that the eruption of the Toba supervolcano around 75,000 years ago nearly wiped homo sapiens off the planet, reducing us to around 1,000 breeding pairs. This theory is offered up as an explanation as to why humans are one of the least genetically diverse of the major mammals, every human alive today is related to a small handful of humans (around 1,000-10,000 people) who survived the explosion.

There’s nothing from the Neolithic era on that can really approach what happened when the Toba volcano erupted. Toba erupted around 2800 cubic km of volcanic material, the largest volcanoes to erupt in recorded human history (like Mt. Tambora in 1815) erupted around 100 cubic km, so the Toba eruption is around 28 times the magnitude of Tambora. When Tambora erupted it created a “year without summer”, Mt. Tambora is in Indonesia and as a result of its eruption, there was no summer in 1815 in North America.

Global warming (although estimates vary) suggests an increase in Average Mean Temperature over the last 100 years of around 0.6 C. After Toba erupted it is estimated Global Mean Temperature dropped at least 3 C in a few years, and caused catastrophic climate change across the entire planet. There is a layer of Toba Ash on the Indian subcontinent (thousands of miles away) that is 20 feet thick.

The thing that is bad, for humans and other animals is climate change, a warm climate isn’t bad, it’s the transition that could be killer (we’re still currently in one of earth’s “cool” periods.) If you “put humans in a void” and could ask them to choose between our current global temperature and say, the global temperature in the Eocene epoch, picking the Eocene would probably be wisest.

During the Eocene epoch temperatures at the equator and current tropical areas were much as they are today, however there were no “arctic” areas. At the very least the arctic had temperate forests akin to the modern-day Pacific Northwest, some studies have show that the poles may have actually been tropical.

A fully tropical world (one with livable temperatures both at equator and pole) has obvious benefits over a world where above a certain latitude agriculture becomes unfeasible.

Unfortunately we don’t get to choose from a void. Our current civilizations, cities, and agricultural systems are built around what we’ve known over the past ~1,000 years or so. Rapid climate change would result in great hardship, it’s no easy feat to move coastal cities, and because of the advantages of sea-ports many major cities the world over are built on coasts.

And before the Eocene epoch became a global tropics, there was a mass extinction event as a result of the rapid warming. The millions of years of cooling and global-tropical weather was great for the species that survived the change and the new ones that evolved, but the ones that got caught in the lurch probably didn’t enjoy it so much.