OK, so the title is intentionally provocative. But it seems to me that atheism can actually be disproved – depending, of course, on what you mean by “atheism.”
Pantheists view the world, the cosmos, as divine, as God. And no atheist denies the existence of the cosmos. Ergo, at least one sort of “God” exists.
I’m being a bit sarcastic here. But hopefully this highlights a key issue related to the definition of atheism, which goes hand in hand with the matter of the definition of God. Is atheism denial that any sort of god exists? If so, the existence of the cosmos, or the existence of Egyptian cats, or the existence of gurus in India, all disprove atheism.
The irony is that many atheists respond to this by denying that such entities are “really” gods.But that is just the adoption on their part of a particular definition of Godhood, as defined within the Abrahamic monotheistic religions, which adopted that perspective in their polemical denigration of other religious viewpoints.
And so when atheists adopt this view of who or what does or does not constitute a “real God,” they are implicitly saying that the religions that most of them reject most vehemently are theologically correct. And that seems to me quite odd.
The alternative is to acknowledge that atheism means the rejection of a certain sort of god, in particular, the supernatural, anthropomorphic sort.
But of course, that stance has the corollary that some religious viewpoints, such as Deism, pantheism, and panentheism, may not be as radically at odds with their atheist stance as the more simplistic rhetoric of “denying the existence of any and all gods of any kind” suggests.