Why do some scientists mention a post human world?

Question

why do they assume we will vanish from the earth?

Answer 1

We are very rapidly producing poisons with no safe way of disposing of the dangerous waste . Eventually , we may poison ourselves out of existence .

Another possibility is the destroying of the plankton and forests that provide us with the oxygen that we must have .

The only question is , will any living thing survive in order to continue the next phase of evolution ?

Answer 2

They pose a great stance behind their reasoning.

For one thing, the EASIEST way for humans to become extinct is more subtle than you think..

Biologically speaking, if we look at the deadliest diseases on earth that wiped out societies of people (such as smallpox/tuberculosis introduced to the Native Americans by the early settlers; the plague in Europe), I would give these scientists more credit than what the other person mentioned above.

For instance, on top of some of the major catastrophic ways of killing societies of people (nuclear warheads), if people wanted to create silent bombs that leaked out deadly microbiological diseases such as Botulism, (which can wipe out populations humans within hours) that could very well be a real possibility as well.

That's why peaceful foreign relations are so important.

Answer 3

For one of many, or several of very few reasons, scientists mention a post-human world.  

First, it's infinitely possible.  Between the anthropogenic weapons and the natural ones, we've painted ourselves into a bit of a corner.  Bombs, bugs, tidal waves, glacial galloping, soil exhaustion, famine, drought, unstoppable fires that we've perpetuated by putting out all the small ones over the years, and the insistence that everyone should think, speak, and act just like "us"....you name it it's out there.  

It's a necessary thing to consider this planet as continuing on without us.  In a way, it's contemplating death on a macro scale.  The human animal as a species grasping its mortality.  To boot, it's an effective way to get Joe Shmo to pay attention to something other than his level of immediate comfort.  Listing the possible consequences of a path can often spur action to avoid said end.

Answer 4

Why wouldn't we?  Most species eventually go extinct or evolve into something new.

Answer 5

humans were supposed to be extinct a long long time ago

according to most scientists we are the most insufficient organisms...with all the diseases and pathogens that exist that could hurt us and with our bodily functions the way they are...its amazing we are still here

and if we dont vanish we will evolve...they think this way because  pretty much every organisms has went through evolution...the earth wont always be the same..according to darwin, he states the the environment is a factor for evolution so if theres an ice age or something or the earth heats up and there is no oxygen left to sustain life you can pretty much bet we're all going to be dead = ]...LMAO

Answer 6

All good things must come to an end?

What goes up must come down?

Answer 7

The future is a great unknown.

There are many factors that can create a post human world such as disease and war.

There was once a time when dinosaurs ruled and roamed the earth.  If any of them were aware of their greater existence I'm sure they would have thought they would survive whatever event caused their extinction.

There is no guarantee that we will not become extinct species ourselves.

Our intelligence and ingenuity do give us an advantage over most species of the past.

One question to ask yourself is why do you assume we are invulnerable?

Answer 8

It's just a fun mental exercise.