Though most Atheists would revolt and object to this idea, this was the ultimate conclusion of Albert Camus, Jean Paul Sartre, Johny Cage, and Bertrand Russel. All of these famous Atheist intellectuals of the past centuries agree that if there is no God, the ULTIMATELY, life is utterly meaningless and becomes truly absurd.
They are not saying that there isn't momentary/personal/subjective meaning - but rather ULTIMATELY every act of every man, woman, and child is meaningless if after death there is nothing more, and if there is no God to infuse life with ultimate purpose, value, and meaning.
Most Atheists aren't courageous (or logical) enough to admit it, and they don't even realize that their "intellectual champions" such as Sartre, Camus, Russel were very bold and blunt about this. In an essay entitled "A Free Man's Worship", Bertrand Russel declared:
"That man is the product of causes which had no prevision of the end they were achieving; that his origin, his growth, his hopes and fears, his loves and his beliefs, are but the outcome of accidental collocations of atoms; that no fire, no heroism, no intensity of thought and feeling, can preserve an individual life beyond the grave; that all the labors of the ages, all the devotion, all the inspiration, all the noonday brightness of human genius, are destined to extinction in the vast death of the solar system, and that the whole temple of man's achievement must inevitably be buried beneath the debris of a universe in ruins -- all these things, if not quite beyond dispute, are yet so nearly certain that no philosophy which rejects them can hope to stand. Only within the scaffolding of these truths, only on the firm foundation of unyielding despair, can the soul's salvation henceforth be safely built."
If an Atheist is ABSOLUTELY HONEST about the logical outworking of his/her worldview, this is the inevitable result: An Ultimate Loss of Meaning, Purpose, and Value.
The problem is, however, that you don't live/think that way. Why not?
Because you want life to have meaning, and believe that at some level it does have ultimate meaning....but this can't be true unless God exists to give it Ultimate Meaning.
Might this be a clue, placed within the innate beliefs and desires of men, to point them towards a Creator God?
"He has set eternity within the heart of man..." - Ecclesiastes 3:11