I would go with running out of food because of the over populated earth.

Sun will explode in a few 1000000 years

i think the population will grow too big for the earth to produce enough food for us and water will become more scarce than gold, so people will fight and eventually turn nuclear to nuclear warfare to get what little water is left. i think in about 200-500 years. just my thoughts

In 500 million years the suns increasing luminosity will accelerate the inorganic co2 cycle and this means that plants won't have enough co2, and then a few million years after, the lack of oxygen in the atmosphere will kill off all complex life.

A billion years after that, the suns luminosity increases further and boils off the oceans.

The global temperature then will be 70 Celsius and Earth will be habitable by some kind of lifeform for 500 million years.
Then a few billion years after, the sun goes red giant and the planet just escapes the suns fiery depths but eventually tidal decay will make it go hurtling into the sun.
the end

No one will know they can just imagine because no one can predict the future and will never be able too.

Asteroids will not kill us in our lifetime because we will know 100 years earlier when it will hit us.

Human wrote In 500 million years the suns increasing luminosity will accelerate the inorganic co2 cycle and this means that plants won't have enough co2, and then a few million years after, the lack of oxygen in the atmosphere will kill off all complex life.

A billion years after that, the suns luminosity increases further and boils off the oceans.

The global temperature then will be 70 Celsius and Earth will be habitable by some kind of lifeform for 500 million years.
Then a few billion years after, the sun goes red giant and the planet just escapes the suns fiery depths but eventually tidal decay will make it go hurtling into the sun.
the end

I Think we will all be dead by then ^_^

Kaizo wrote

Human wrote In 500 million years the suns increasing luminosity will accelerate the inorganic co2 cycle and this means that plants won't have enough co2, and then a few million years after, the lack of oxygen in the atmosphere will kill off all complex life.

A billion years after that, the suns luminosity increases further and boils off the oceans.

The global temperature then will be 70 Celsius and Earth will be habitable by some kind of lifeform for 500 million years.
Then a few billion years after, the sun goes red giant and the planet just escapes the suns fiery depths but eventually tidal decay will make it go hurtling into the sun.
the end

I Think we will all be dead by then ^_^

The question is "How will the world end?"
Not "How will human life end?"

^_^

If the sun does not burn out first then we will either blow each other up or our the food chain will get messed up by either an oil spill or something of that nature and we'll all be :idea:

Well if i have to choose from Ice,Fire,No food, or Meteors. I would have to say from no food because without food you would starve. Also if a bunch of meteors crash to earth then we would also die. So i am not sure!