most likely Religion

Me if Liverpool win a league title. I could not allow it to happen. Also that Mario Kart song is the new definition of epic and I would love that to play before the end of life. Its the perfect extinction song.

Sony fanboys

Microscopic Machines, Aka - The Grey Goo will devour all life on this planet in a effort to feed itself. :D

EDIT: The only things that can wipe out all life on Earth by themselves are:

1) A wayward black hole

2) An insanely large planetary body that breaks the planet into pieces

3) A Gamma ray burst.

Other than that, I stick with human stupidity.

Quilted Toilet Paper and Cows with gas.


After the Earth is in tatters, both the Obama and the Rush shall lead their armies into a bloody battle that shall divide the entire world between the RED and the BLOOD (the Reps vs the Dems).

And we all will die.

But at least the Dems will have healthcare while they await the dark encroach of the Grim Reaper.

War

depends on what you mean all life or just humans

if you mean just humans we are selves either tough nuclear war or a man made super virus

all life - "in about 5 billion years, it will enter a red giant phase, its outer layers expanding as the hydrogen fuel in the core is consumed and the core contracts and heats up. Helium fusion will begin when the core temperature reaches around 100 million kelvins and will produce carbon, entering the asymptotic giant branch phase.Earth's fate is precarious. As a red giant, the Sun will have a maximum radius beyond the Earth's current orbit, 1 AU (1.5×1011 m), 250 times the present radius of the Sun. However, by the time it is an asymptotic giant branch star, the Sun will have lost roughly 30% of its present mass due to a stellar wind, so the orbits of the planets will move outward. If it were only for this, Earth would probably be spared, but new research suggests that Earth will be swallowed by the Sun owing to tidal interactions. Even if Earth would escape incineration in the Sun, still all its water will be boiled away and most of its atmosphere would escape into space. In fact, even during its current life in the main sequence, the Sun is gradually becoming more luminous (about 10% every 1 billion years), and its surface temperature is slowly rising. The Sun used to be fainter in the past, which is possibly the reason why life on Earth has only existed for about 1 billion years on land. The increase in solar temperatures is such that already in about a billion years, the surface of the Earth will become too hot for liquid water to exist, ending all terrestrial life"

taken from http://en.wikipedia.org/wiki/Sun#Life_cycle

or one of these http://en.wikipedia.org/wiki/Risks_to_civilization,_humans_and_planet_Earth

humans, there are 2 possible ways, or we destroy earth rescourses and fuck everything or erath gets angry and fuck us up.

You are right

Did you know that the number of air plane crashes at the hands of terrorist birds are up? Birds are doing Suicide Bombing into jet engines and in that way causing planes to crash or malfunction.

And the Bees have stopped working and the cows are mad.