The Absence of Proof Is Not Proof of Absence!
One of the great and most widely read English poets of the 18th century, William Cowper, wrote: "The absence of proof is not proof of absence." This caveat alone should humble the scientist who seeks to prove that God does not exist by suggesting that there is no proof that God does exist! There were those who sought to prove that our planet was flat with similar argumentation. Today, we look upon them as primitive in their thinking, if not foolish.
Furthermore, good science is equally humble in distinguishing between what it can and cannot achieve. Good science aims to prove null-hypotheses, meaning it can disprove theories that explain phenomena insufficiently, but, it can only hypothesize and theorize, based upon data currently extant and available, to explain phenomena. As such, by the standards that science itself employs, the burden of disproof of the theory of the existence of God is placed squarely upon my opposition in this debate.